Binh T. Ngo, MD

In April 2023, the US Preventive Services Task Force (USPSTF) issued a controversial recommendation that the current evidence is insufficient to assess the benefits vs harms of visual skin examination by clinicians for skin cancer screening in adolescents and adults who do not have signs or symptoms of skin cancer.^1,2 This recommendation by the USPSTF has not changed in a quarter century,³ but a recent study described an interesting paradox that should trigger wide evaluation and debate.

Patel et al⁴ analyzed data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program from January 2000 to December 2018 to identify adults with a diagnosis of first primary melanoma in situ (MIS). Overall mortality was then determined through the National Vital Statistics System, which provides cause-of-death information for all deaths in the United States. The authors found 137,872 patients who had 1—and only 1—MIS discovered over the observation period. These patients predominantly were White (96.7%), and the mean (SD) age at diagnosis was 61.9 (16.5) years. During 910,308 total person-years of follow-up (mean [SD], 6.6 [5.1] years), 893 (0.6%) patients died of melanoma and 17,327 (12.6%) died of any cause. The 15-year melanoma-specific standardized mortality rate (SMR) was 1.89 (95% CI, 1.77-2.02), yet the 15-year overall survival relative to matched population controls was 112.4% (95% CI, 112.0%-112.8%), thus all-cause SMR was significantly lower at 0.68 (95% CI, 0.67-0.7). Although MIS was associated with a small increase in cohort melanoma mortality, overall mortality was actually lower than in the general population.⁴

Patel et al⁴ did a further broader search that included an additional 18,379 patients who also experienced a second primary melanoma, of which 6751 (36.7%) were invasive and 11,628 (63.3%) were in situ, with a melanoma-specific survival of 98.2% (95% CI, 97.6%-98.5%). Yet relative all-cause survival was significantly higher at 126.7% (95% CI, 125.5%-128.0%). Even among patients in whom a second primary melanoma was invasive, melanoma-specific survival was reduced to 91.1% (95% CI, 90.0%-92.1%), but relative all-cause survival was 116.7% (95% CI, 115%-118.4%). These data in the overall cohort of 155,251 patients showed a discordance between melanoma mortality, which was 4.27-times higher than in the general population (SMR, 4.27; 95% CI, 4.07-4.48), and a lower risk for death from all causes that was approximately 27% lower than in the general population (SMR, 0.73; 95% CI, 0.72-0.74). The authors showed that their findings were not associated with socioeconomic status.⁴

The analysis by Patel et al⁴ is now the second study in the literature to show this discordant melanoma survival pattern. In an earlier Australian study of 2452 melanoma patients, Watts et al⁵ reported that melanoma detection during routine skin checks was associated with a 25% lower all-cause mortality (hazard ratio, 0.75; 95% CI, 0.63-0.90) but not melanoma-specific mortality after multivariable adjustment for a variety of factors including socioeconomic status.These analyses by 2 different groups of investigators have broad implications. Both groups suggested that the improved life span in melanoma patients may be due to health-seeking behavior, which has been defined as “any action undertaken by individuals who perceive themselves to have a health problem or to be ill for the purpose of finding an appropriate remedy.”⁶

Once treated for melanoma, it is clear that patients are likely to return at regular intervals for thorough full-body skin examinations, but this activity alone could not be responsible for improved all-cause mortality in the face of increased melanoma-specific mortality. It seems the authors are implying a broader concept of good health behavior, originally defined by MacKian⁷ as encompassing “activities undertaken to maintain good health, to prevent ill health, as well as dealing with any departure from a good state of health,” such as overt behavioral patterns, actions, and habits with the goal of maintenance, restoration, and improvement of one’s health. A variety of behaviors fall within such a definition including smoking cessation, decreased alcohol use, good diet, more physical activity, safe sexual behavior, scheduling physician visits, medication adherence, vaccination, and yes—screening examinations for health problems.⁸

The concept that individuals who are diagnosed with melanoma fall into a pattern of good health behavior is an interesting hypothesis that must remain speculative until the multiple aspects of good health behavior are rigorously studied. This concept coexists with the hypothesis of melanoma “overdiagnosis”—the idea that many melanomas are detected that will never lead to death.⁹ Both concepts deserve further analysis. Unquestionably, a randomized controlled trial could never recruit patients willing to undergo long-term untreated observation of their melanomas to test the hypothesis that their melanoma diagnosis would eventually lead to death. Furthermore, Patel et al⁴ do suggest that even MIS carries a small but measurable increased risk for death from the disease, which is not particularly supportive of the overdiagnosis hypothesis; however, analysis of the concept that improved individual health behavior is at least in part responsible for the first discovery of melanomas is certainly approachable. Here is the key question: Did the melanoma diagnosis trigger a sudden change in multiple aspects of health behavior that led to significant all-cause mortality benefits? The average age of the population studied by Patel et al⁴ was approximately 62 years. One wonders whether the consequences of a lifetime of established health behavior patterns can be rapidly ­modified—certainly possible but again remains to be proven by further studies.

Conversely, the alternative hypothesis is that discovery of MIS was the result of active pursuit of self-examination and screening procedures as part of individually ingrained good health behavior over a lifetime. Goodwin et al¹⁰ carried out a study in a sample of the Medicare population aged 69 to 90 years looking at men who had prostate cancer screening via prostate-specific antigen measurement and women who had undergone mammography in older age, compared to the contrast population who had not had these screening procedures. They tracked date of death in Medicare enrollment files. They identified 543,970 women and 362,753 men who were aged 69 to 90 years as of January 1, 2003. Patients were stratified by life expectancy based on age and comorbidity. Within each stratum, the patients with cancer screening had higher actual median survival than those who were not screened, with differences ranging from 1.7 to 2.1 years for women and 0.9 to 1.1 years for men.¹⁰ These results were not the result of lower prostate or breast cancer mortality. Rather, one surmises that other health factors yielded lower mortality in the screened cohorts.

A full-body skin examination is a time-consuming process. Patients who come to their physician for a routine annual physical don’t expect a skin examination and very few physicians have the time for a long detailed full-body skin examination. When the patient presents to a dermatologist for an examination, it often is because they have real concerns; for example, they may have had a family member who died of skin cancer, or the patient themself may have noticed a worrisome lesion. Patients, not physicians, are the drivers of skin cancer screening, a fact that often is dismissed by those who are not necessarily supportive of the practice.

In light of the findings of Patel et al,⁴ it is essential that the USPSTF reviews be reanalyzed to compare skin cancer–specific mortality, all-cause mortality, and lifespan in individuals who pursue skin cancer screening; the reanalysis also should not be exclusively limited to survival. With the advent of the immune checkpoint inhibitors, patients with metastatic melanoma are living much longer.¹¹ The burden of living with metastatic cancer must be characterized and measured to have a complete picture and a valid analysis.

After the release of the USPSTF recommendation, there have been calls for large-scale studies to prove the benefits of skin cancer screening.¹² Such studies may be valuable; however, if the hypothesis that overall healthy behavior as the major outcome determinant is substantiated, it may prove quite challenging to perform tests of association with specific interventions. It has been shown that skin cancer screening does lead to discovery of more melanomas,¹³ yet in light of the paradox described by Patel et al,⁴ it also is likely that causes of death other than melanoma impact overall mortality. Patients who pursue skin examinations may engage in multiple different health activities that are beneficial in the long term, making it difficult to analyze the specific benefit of skin cancer screening in isolation. It may prove difficult to ask patients to omit selected aspects of healthy behavior to try to prove the point. At this time, there is much more work to be done prior to offering opinions on the importance of skin cancer examination in isolation to improve overall health care. In the meantime, dermatologists owe it to our patients to continue to diligently pursue thorough and detailed skin examinations.

In April 2023, the US Preventive Services Task Force (USPSTF) issued a controversial recommendation that the current evidence is insufficient to assess the benefits vs harms of visual skin examination by clinicians for skin cancer screening in adolescents and adults who do not have signs or symptoms of skin cancer.^1,2 This recommendation by the USPSTF has not changed in a quarter century,³ but a recent study described an interesting paradox that should trigger wide evaluation and debate.

Patel et al⁴ analyzed data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program from January 2000 to December 2018 to identify adults with a diagnosis of first primary melanoma in situ (MIS). Overall mortality was then determined through the National Vital Statistics System, which provides cause-of-death information for all deaths in the United States. The authors found 137,872 patients who had 1—and only 1—MIS discovered over the observation period. These patients predominantly were White (96.7%), and the mean (SD) age at diagnosis was 61.9 (16.5) years. During 910,308 total person-years of follow-up (mean [SD], 6.6 [5.1] years), 893 (0.6%) patients died of melanoma and 17,327 (12.6%) died of any cause. The 15-year melanoma-specific standardized mortality rate (SMR) was 1.89 (95% CI, 1.77-2.02), yet the 15-year overall survival relative to matched population controls was 112.4% (95% CI, 112.0%-112.8%), thus all-cause SMR was significantly lower at 0.68 (95% CI, 0.67-0.7). Although MIS was associated with a small increase in cohort melanoma mortality, overall mortality was actually lower than in the general population.⁴

Patel et al⁴ did a further broader search that included an additional 18,379 patients who also experienced a second primary melanoma, of which 6751 (36.7%) were invasive and 11,628 (63.3%) were in situ, with a melanoma-specific survival of 98.2% (95% CI, 97.6%-98.5%). Yet relative all-cause survival was significantly higher at 126.7% (95% CI, 125.5%-128.0%). Even among patients in whom a second primary melanoma was invasive, melanoma-specific survival was reduced to 91.1% (95% CI, 90.0%-92.1%), but relative all-cause survival was 116.7% (95% CI, 115%-118.4%). These data in the overall cohort of 155,251 patients showed a discordance between melanoma mortality, which was 4.27-times higher than in the general population (SMR, 4.27; 95% CI, 4.07-4.48), and a lower risk for death from all causes that was approximately 27% lower than in the general population (SMR, 0.73; 95% CI, 0.72-0.74). The authors showed that their findings were not associated with socioeconomic status.⁴

The analysis by Patel et al⁴ is now the second study in the literature to show this discordant melanoma survival pattern. In an earlier Australian study of 2452 melanoma patients, Watts et al⁵ reported that melanoma detection during routine skin checks was associated with a 25% lower all-cause mortality (hazard ratio, 0.75; 95% CI, 0.63-0.90) but not melanoma-specific mortality after multivariable adjustment for a variety of factors including socioeconomic status.These analyses by 2 different groups of investigators have broad implications. Both groups suggested that the improved life span in melanoma patients may be due to health-seeking behavior, which has been defined as “any action undertaken by individuals who perceive themselves to have a health problem or to be ill for the purpose of finding an appropriate remedy.”⁶

Once treated for melanoma, it is clear that patients are likely to return at regular intervals for thorough full-body skin examinations, but this activity alone could not be responsible for improved all-cause mortality in the face of increased melanoma-specific mortality. It seems the authors are implying a broader concept of good health behavior, originally defined by MacKian⁷ as encompassing “activities undertaken to maintain good health, to prevent ill health, as well as dealing with any departure from a good state of health,” such as overt behavioral patterns, actions, and habits with the goal of maintenance, restoration, and improvement of one’s health. A variety of behaviors fall within such a definition including smoking cessation, decreased alcohol use, good diet, more physical activity, safe sexual behavior, scheduling physician visits, medication adherence, vaccination, and yes—screening examinations for health problems.⁸

The concept that individuals who are diagnosed with melanoma fall into a pattern of good health behavior is an interesting hypothesis that must remain speculative until the multiple aspects of good health behavior are rigorously studied. This concept coexists with the hypothesis of melanoma “overdiagnosis”—the idea that many melanomas are detected that will never lead to death.⁹ Both concepts deserve further analysis. Unquestionably, a randomized controlled trial could never recruit patients willing to undergo long-term untreated observation of their melanomas to test the hypothesis that their melanoma diagnosis would eventually lead to death. Furthermore, Patel et al⁴ do suggest that even MIS carries a small but measurable increased risk for death from the disease, which is not particularly supportive of the overdiagnosis hypothesis; however, analysis of the concept that improved individual health behavior is at least in part responsible for the first discovery of melanomas is certainly approachable. Here is the key question: Did the melanoma diagnosis trigger a sudden change in multiple aspects of health behavior that led to significant all-cause mortality benefits? The average age of the population studied by Patel et al⁴ was approximately 62 years. One wonders whether the consequences of a lifetime of established health behavior patterns can be rapidly ­modified—certainly possible but again remains to be proven by further studies.

Conversely, the alternative hypothesis is that discovery of MIS was the result of active pursuit of self-examination and screening procedures as part of individually ingrained good health behavior over a lifetime. Goodwin et al¹⁰ carried out a study in a sample of the Medicare population aged 69 to 90 years looking at men who had prostate cancer screening via prostate-specific antigen measurement and women who had undergone mammography in older age, compared to the contrast population who had not had these screening procedures. They tracked date of death in Medicare enrollment files. They identified 543,970 women and 362,753 men who were aged 69 to 90 years as of January 1, 2003. Patients were stratified by life expectancy based on age and comorbidity. Within each stratum, the patients with cancer screening had higher actual median survival than those who were not screened, with differences ranging from 1.7 to 2.1 years for women and 0.9 to 1.1 years for men.¹⁰ These results were not the result of lower prostate or breast cancer mortality. Rather, one surmises that other health factors yielded lower mortality in the screened cohorts.

A full-body skin examination is a time-consuming process. Patients who come to their physician for a routine annual physical don’t expect a skin examination and very few physicians have the time for a long detailed full-body skin examination. When the patient presents to a dermatologist for an examination, it often is because they have real concerns; for example, they may have had a family member who died of skin cancer, or the patient themself may have noticed a worrisome lesion. Patients, not physicians, are the drivers of skin cancer screening, a fact that often is dismissed by those who are not necessarily supportive of the practice.

In light of the findings of Patel et al,⁴ it is essential that the USPSTF reviews be reanalyzed to compare skin cancer–specific mortality, all-cause mortality, and lifespan in individuals who pursue skin cancer screening; the reanalysis also should not be exclusively limited to survival. With the advent of the immune checkpoint inhibitors, patients with metastatic melanoma are living much longer.¹¹ The burden of living with metastatic cancer must be characterized and measured to have a complete picture and a valid analysis.

After the release of the USPSTF recommendation, there have been calls for large-scale studies to prove the benefits of skin cancer screening.¹² Such studies may be valuable; however, if the hypothesis that overall healthy behavior as the major outcome determinant is substantiated, it may prove quite challenging to perform tests of association with specific interventions. It has been shown that skin cancer screening does lead to discovery of more melanomas,¹³ yet in light of the paradox described by Patel et al,⁴ it also is likely that causes of death other than melanoma impact overall mortality. Patients who pursue skin examinations may engage in multiple different health activities that are beneficial in the long term, making it difficult to analyze the specific benefit of skin cancer screening in isolation. It may prove difficult to ask patients to omit selected aspects of healthy behavior to try to prove the point. At this time, there is much more work to be done prior to offering opinions on the importance of skin cancer examination in isolation to improve overall health care. In the meantime, dermatologists owe it to our patients to continue to diligently pursue thorough and detailed skin examinations.

In April 2023, the US Preventive Services Task Force (USPSTF) issued a controversial recommendation that the current evidence is insufficient to assess the benefits vs harms of visual skin examination by clinicians for skin cancer screening in adolescents and adults who do not have signs or symptoms of skin cancer.^1,2 This recommendation by the USPSTF has not changed in a quarter century,³ but a recent study described an interesting paradox that should trigger wide evaluation and debate.

Patel et al⁴ analyzed data from the National Cancer Institute’s Surveillance, Epidemiology, and End Results Program from January 2000 to December 2018 to identify adults with a diagnosis of first primary melanoma in situ (MIS). Overall mortality was then determined through the National Vital Statistics System, which provides cause-of-death information for all deaths in the United States. The authors found 137,872 patients who had 1—and only 1—MIS discovered over the observation period. These patients predominantly were White (96.7%), and the mean (SD) age at diagnosis was 61.9 (16.5) years. During 910,308 total person-years of follow-up (mean [SD], 6.6 [5.1] years), 893 (0.6%) patients died of melanoma and 17,327 (12.6%) died of any cause. The 15-year melanoma-specific standardized mortality rate (SMR) was 1.89 (95% CI, 1.77-2.02), yet the 15-year overall survival relative to matched population controls was 112.4% (95% CI, 112.0%-112.8%), thus all-cause SMR was significantly lower at 0.68 (95% CI, 0.67-0.7). Although MIS was associated with a small increase in cohort melanoma mortality, overall mortality was actually lower than in the general population.⁴

Patel et al⁴ did a further broader search that included an additional 18,379 patients who also experienced a second primary melanoma, of which 6751 (36.7%) were invasive and 11,628 (63.3%) were in situ, with a melanoma-specific survival of 98.2% (95% CI, 97.6%-98.5%). Yet relative all-cause survival was significantly higher at 126.7% (95% CI, 125.5%-128.0%). Even among patients in whom a second primary melanoma was invasive, melanoma-specific survival was reduced to 91.1% (95% CI, 90.0%-92.1%), but relative all-cause survival was 116.7% (95% CI, 115%-118.4%). These data in the overall cohort of 155,251 patients showed a discordance between melanoma mortality, which was 4.27-times higher than in the general population (SMR, 4.27; 95% CI, 4.07-4.48), and a lower risk for death from all causes that was approximately 27% lower than in the general population (SMR, 0.73; 95% CI, 0.72-0.74). The authors showed that their findings were not associated with socioeconomic status.⁴

The analysis by Patel et al⁴ is now the second study in the literature to show this discordant melanoma survival pattern. In an earlier Australian study of 2452 melanoma patients, Watts et al⁵ reported that melanoma detection during routine skin checks was associated with a 25% lower all-cause mortality (hazard ratio, 0.75; 95% CI, 0.63-0.90) but not melanoma-specific mortality after multivariable adjustment for a variety of factors including socioeconomic status.These analyses by 2 different groups of investigators have broad implications. Both groups suggested that the improved life span in melanoma patients may be due to health-seeking behavior, which has been defined as “any action undertaken by individuals who perceive themselves to have a health problem or to be ill for the purpose of finding an appropriate remedy.”⁶

Once treated for melanoma, it is clear that patients are likely to return at regular intervals for thorough full-body skin examinations, but this activity alone could not be responsible for improved all-cause mortality in the face of increased melanoma-specific mortality. It seems the authors are implying a broader concept of good health behavior, originally defined by MacKian⁷ as encompassing “activities undertaken to maintain good health, to prevent ill health, as well as dealing with any departure from a good state of health,” such as overt behavioral patterns, actions, and habits with the goal of maintenance, restoration, and improvement of one’s health. A variety of behaviors fall within such a definition including smoking cessation, decreased alcohol use, good diet, more physical activity, safe sexual behavior, scheduling physician visits, medication adherence, vaccination, and yes—screening examinations for health problems.⁸

The concept that individuals who are diagnosed with melanoma fall into a pattern of good health behavior is an interesting hypothesis that must remain speculative until the multiple aspects of good health behavior are rigorously studied. This concept coexists with the hypothesis of melanoma “overdiagnosis”—the idea that many melanomas are detected that will never lead to death.⁹ Both concepts deserve further analysis. Unquestionably, a randomized controlled trial could never recruit patients willing to undergo long-term untreated observation of their melanomas to test the hypothesis that their melanoma diagnosis would eventually lead to death. Furthermore, Patel et al⁴ do suggest that even MIS carries a small but measurable increased risk for death from the disease, which is not particularly supportive of the overdiagnosis hypothesis; however, analysis of the concept that improved individual health behavior is at least in part responsible for the first discovery of melanomas is certainly approachable. Here is the key question: Did the melanoma diagnosis trigger a sudden change in multiple aspects of health behavior that led to significant all-cause mortality benefits? The average age of the population studied by Patel et al⁴ was approximately 62 years. One wonders whether the consequences of a lifetime of established health behavior patterns can be rapidly ­modified—certainly possible but again remains to be proven by further studies.

Conversely, the alternative hypothesis is that discovery of MIS was the result of active pursuit of self-examination and screening procedures as part of individually ingrained good health behavior over a lifetime. Goodwin et al¹⁰ carried out a study in a sample of the Medicare population aged 69 to 90 years looking at men who had prostate cancer screening via prostate-specific antigen measurement and women who had undergone mammography in older age, compared to the contrast population who had not had these screening procedures. They tracked date of death in Medicare enrollment files. They identified 543,970 women and 362,753 men who were aged 69 to 90 years as of January 1, 2003. Patients were stratified by life expectancy based on age and comorbidity. Within each stratum, the patients with cancer screening had higher actual median survival than those who were not screened, with differences ranging from 1.7 to 2.1 years for women and 0.9 to 1.1 years for men.¹⁰ These results were not the result of lower prostate or breast cancer mortality. Rather, one surmises that other health factors yielded lower mortality in the screened cohorts.

A full-body skin examination is a time-consuming process. Patients who come to their physician for a routine annual physical don’t expect a skin examination and very few physicians have the time for a long detailed full-body skin examination. When the patient presents to a dermatologist for an examination, it often is because they have real concerns; for example, they may have had a family member who died of skin cancer, or the patient themself may have noticed a worrisome lesion. Patients, not physicians, are the drivers of skin cancer screening, a fact that often is dismissed by those who are not necessarily supportive of the practice.

In light of the findings of Patel et al,⁴ it is essential that the USPSTF reviews be reanalyzed to compare skin cancer–specific mortality, all-cause mortality, and lifespan in individuals who pursue skin cancer screening; the reanalysis also should not be exclusively limited to survival. With the advent of the immune checkpoint inhibitors, patients with metastatic melanoma are living much longer.¹¹ The burden of living with metastatic cancer must be characterized and measured to have a complete picture and a valid analysis.

After the release of the USPSTF recommendation, there have been calls for large-scale studies to prove the benefits of skin cancer screening.¹² Such studies may be valuable; however, if the hypothesis that overall healthy behavior as the major outcome determinant is substantiated, it may prove quite challenging to perform tests of association with specific interventions. It has been shown that skin cancer screening does lead to discovery of more melanomas,¹³ yet in light of the paradox described by Patel et al,⁴ it also is likely that causes of death other than melanoma impact overall mortality. Patients who pursue skin examinations may engage in multiple different health activities that are beneficial in the long term, making it difficult to analyze the specific benefit of skin cancer screening in isolation. It may prove difficult to ask patients to omit selected aspects of healthy behavior to try to prove the point. At this time, there is much more work to be done prior to offering opinions on the importance of skin cancer examination in isolation to improve overall health care. In the meantime, dermatologists owe it to our patients to continue to diligently pursue thorough and detailed skin examinations.

Dermatology certainly is the most visual medical specialty. In the current era of powerful electronic imaging and laboratory techniques, the skills of physical diagnosis seem to have become less important in medicine—not so in dermatology, in which the experienced clinician is able to identify many conditions by simply looking at the skin. Of course, dermatologists do heavily rely on dermatopathologists to microscopically visualize biopsies to distinguish diseases. Even as we acknowledge the dominant role of visual recognition, there is increasing progress in making clinical determinations based on molecular events. The era of genomic dermatology is here.

The Genodermatoses

There are more than 500 dermatologic conditions resulting from heritable mutational events.¹ The rarity of most of these diseases and variability in phenotypic manifestations presents considerable diagnostic challenges, typically the province of a select group of clinical pediatric dermatologists whose abilities have been developed by experience.² However, the addition of genomic analysis has now made reliable identification more accessible to a wider group of clinicians.³ The Human Genome Project was arguably the most successful health policy endeavor in human history, promoting the development of massive automated, information theory–driven applications to analyze DNA sequences.⁴ We all think of DNA analysis as the ultimate means to detect mutations by sequencing whole exomes—and in fact the entire genome of affected individuals searching for mutations—but DNA sequencing often is insufficient to detect mutations in noncoding regions of genes and to identify abnormalities of gene expression (eg, splice variants). Building on the advances in high-throughput nucleic acid sequencing and massive computerized analysis, the field has now taken a quantum leap further to sequence transcribed RNA to detect abnormalities.⁵

The techniques are straightforward: RNA is isolated and reverse transcribed to complementary DNA. The complementary DNA is amplified and then processed by high-throughput sequencers. The sequences are then identified by computer algorithms. It is possible to fully define the transcriptomes of multiple genes, even reaching the threshold of resolution of gene expression emanating from a single cell.⁶

Studying Gene Expression for Malignant Melanoma

As much as we rely on visual interpretations, we acknowledge that many conditions look very similar, whether to the naked eye or under the microscope. This is true for rare diseases but also for the rashes we routinely see. A group of investigators recently used RNA transcriptome sequencing to analyze differences between atopic dermatitis and psoriasis, permitting better differentiation of these 2 common conditions.⁷

One of the greatest challenges confronting dermatologists and their dermatopathologist partners is to distinguish malignant melanoma from benign nevi.⁸ Despite staining for a number of molecular markers, some lesions defy histopathology, such as distinguishing benign and malignant Spitz nevi; however, recent work on RNA transcriptomes suggests that gene expression may increase confidence in assessing atypical Spitz nevi.⁹ A 23-gene expression panel has yielded a sensitivity of 91.5% and a specificity of 92.5% in differentiating benign nevi from malignant melanoma.¹⁰

From the Research Laboratory to Routine Clinical Use

Undoubtedly, it is a large step from proof-of-concept studies to accepted clinical use. The ultimate achievement for a laboratory technique is to enter approved clinical use. Gene expression panels have now been approved by numerous third-party insurers to help predict future clinical evolution of biopsied melanomas. Although early in situ melanomas are eminently curable by wide excision, lesions that have more concerning characteristics (eg, depth >0.8 mm, ulceration) may progress to metastatic disease. The gratifying success of checkpoint inhibitor therapy has improved the previously dismal outlook for advanced melanomas.¹¹ Dermatologists search for clues to suggest which patients may benefit from adjuvant therapy. Sentinel lymph node biopsy (SLNB) has been a standard-of-care technique to help make this determination.¹²

It has now been demonstrated that gene expression array analysis can provide evidence complementing SLNB results or even independent of SLNB results. In extensive validation studies, a 31-gene expression panel analyzing initial melanoma biopsy specimens showed predictive value for later recurrence and development of metastatic disease.^13,14 The gene expression studies have identified patients with negative SLNBs who have gone on to develop metastatic melanomas.¹⁵ It has been suggested that gene expression panel diagnosis may reduce the need for invasive SLNBs in patients in whom the surgical procedure may involve risk.¹⁶

Looking to the Future

The progress of science is the result of many small steps building on prior work. The terms breakthrough and game changer in medicine have been popularized by the media and rarely are valid. On the contrary, sequential development of methods over many years has preceded the acclaimed successes of medical research; for example, the best-known medical breakthrough—that of Salk’s inactivated polio vaccine—was preceded by the use of an inactivated polio vaccine by Brodie and Park¹⁷ in 1935. However, it was the development of tissue culture of poliomyelitis virus by Enders et al¹⁸ that provided the methodology to Salk’s group to produce their inactivated polio vaccine.

The ability to go beyond our visual senses will be of great importance in characterizing the variability of skin diseases, especially in skin of color patients; for example, acral melanoma is perhaps the primary melanocytic malignancy in darker-skinned patients and is the target of RNA transcriptomic research.¹⁹ Progress is continuing on gene therapy for a growing number of skin conditions.^20,21 In vivo correction of abnormal genes is being attempted for a number of inherited cutaneous diseases,²² notably for disorders of skin fragility.²³ For now, we welcome the addition of genomic capabilities to the visual practice of dermatology and the capability to go beyond that which we can see with our eyes.

Dermatology certainly is the most visual medical specialty. In the current era of powerful electronic imaging and laboratory techniques, the skills of physical diagnosis seem to have become less important in medicine—not so in dermatology, in which the experienced clinician is able to identify many conditions by simply looking at the skin. Of course, dermatologists do heavily rely on dermatopathologists to microscopically visualize biopsies to distinguish diseases. Even as we acknowledge the dominant role of visual recognition, there is increasing progress in making clinical determinations based on molecular events. The era of genomic dermatology is here.

The Genodermatoses

There are more than 500 dermatologic conditions resulting from heritable mutational events.¹ The rarity of most of these diseases and variability in phenotypic manifestations presents considerable diagnostic challenges, typically the province of a select group of clinical pediatric dermatologists whose abilities have been developed by experience.² However, the addition of genomic analysis has now made reliable identification more accessible to a wider group of clinicians.³ The Human Genome Project was arguably the most successful health policy endeavor in human history, promoting the development of massive automated, information theory–driven applications to analyze DNA sequences.⁴ We all think of DNA analysis as the ultimate means to detect mutations by sequencing whole exomes—and in fact the entire genome of affected individuals searching for mutations—but DNA sequencing often is insufficient to detect mutations in noncoding regions of genes and to identify abnormalities of gene expression (eg, splice variants). Building on the advances in high-throughput nucleic acid sequencing and massive computerized analysis, the field has now taken a quantum leap further to sequence transcribed RNA to detect abnormalities.⁵

The techniques are straightforward: RNA is isolated and reverse transcribed to complementary DNA. The complementary DNA is amplified and then processed by high-throughput sequencers. The sequences are then identified by computer algorithms. It is possible to fully define the transcriptomes of multiple genes, even reaching the threshold of resolution of gene expression emanating from a single cell.⁶

Studying Gene Expression for Malignant Melanoma

As much as we rely on visual interpretations, we acknowledge that many conditions look very similar, whether to the naked eye or under the microscope. This is true for rare diseases but also for the rashes we routinely see. A group of investigators recently used RNA transcriptome sequencing to analyze differences between atopic dermatitis and psoriasis, permitting better differentiation of these 2 common conditions.⁷

One of the greatest challenges confronting dermatologists and their dermatopathologist partners is to distinguish malignant melanoma from benign nevi.⁸ Despite staining for a number of molecular markers, some lesions defy histopathology, such as distinguishing benign and malignant Spitz nevi; however, recent work on RNA transcriptomes suggests that gene expression may increase confidence in assessing atypical Spitz nevi.⁹ A 23-gene expression panel has yielded a sensitivity of 91.5% and a specificity of 92.5% in differentiating benign nevi from malignant melanoma.¹⁰

From the Research Laboratory to Routine Clinical Use

Undoubtedly, it is a large step from proof-of-concept studies to accepted clinical use. The ultimate achievement for a laboratory technique is to enter approved clinical use. Gene expression panels have now been approved by numerous third-party insurers to help predict future clinical evolution of biopsied melanomas. Although early in situ melanomas are eminently curable by wide excision, lesions that have more concerning characteristics (eg, depth >0.8 mm, ulceration) may progress to metastatic disease. The gratifying success of checkpoint inhibitor therapy has improved the previously dismal outlook for advanced melanomas.¹¹ Dermatologists search for clues to suggest which patients may benefit from adjuvant therapy. Sentinel lymph node biopsy (SLNB) has been a standard-of-care technique to help make this determination.¹²

It has now been demonstrated that gene expression array analysis can provide evidence complementing SLNB results or even independent of SLNB results. In extensive validation studies, a 31-gene expression panel analyzing initial melanoma biopsy specimens showed predictive value for later recurrence and development of metastatic disease.^13,14 The gene expression studies have identified patients with negative SLNBs who have gone on to develop metastatic melanomas.¹⁵ It has been suggested that gene expression panel diagnosis may reduce the need for invasive SLNBs in patients in whom the surgical procedure may involve risk.¹⁶

Looking to the Future

The progress of science is the result of many small steps building on prior work. The terms breakthrough and game changer in medicine have been popularized by the media and rarely are valid. On the contrary, sequential development of methods over many years has preceded the acclaimed successes of medical research; for example, the best-known medical breakthrough—that of Salk’s inactivated polio vaccine—was preceded by the use of an inactivated polio vaccine by Brodie and Park¹⁷ in 1935. However, it was the development of tissue culture of poliomyelitis virus by Enders et al¹⁸ that provided the methodology to Salk’s group to produce their inactivated polio vaccine.

The ability to go beyond our visual senses will be of great importance in characterizing the variability of skin diseases, especially in skin of color patients; for example, acral melanoma is perhaps the primary melanocytic malignancy in darker-skinned patients and is the target of RNA transcriptomic research.¹⁹ Progress is continuing on gene therapy for a growing number of skin conditions.^20,21 In vivo correction of abnormal genes is being attempted for a number of inherited cutaneous diseases,²² notably for disorders of skin fragility.²³ For now, we welcome the addition of genomic capabilities to the visual practice of dermatology and the capability to go beyond that which we can see with our eyes.

Dermatology certainly is the most visual medical specialty. In the current era of powerful electronic imaging and laboratory techniques, the skills of physical diagnosis seem to have become less important in medicine—not so in dermatology, in which the experienced clinician is able to identify many conditions by simply looking at the skin. Of course, dermatologists do heavily rely on dermatopathologists to microscopically visualize biopsies to distinguish diseases. Even as we acknowledge the dominant role of visual recognition, there is increasing progress in making clinical determinations based on molecular events. The era of genomic dermatology is here.

The Genodermatoses

There are more than 500 dermatologic conditions resulting from heritable mutational events.¹ The rarity of most of these diseases and variability in phenotypic manifestations presents considerable diagnostic challenges, typically the province of a select group of clinical pediatric dermatologists whose abilities have been developed by experience.² However, the addition of genomic analysis has now made reliable identification more accessible to a wider group of clinicians.³ The Human Genome Project was arguably the most successful health policy endeavor in human history, promoting the development of massive automated, information theory–driven applications to analyze DNA sequences.⁴ We all think of DNA analysis as the ultimate means to detect mutations by sequencing whole exomes—and in fact the entire genome of affected individuals searching for mutations—but DNA sequencing often is insufficient to detect mutations in noncoding regions of genes and to identify abnormalities of gene expression (eg, splice variants). Building on the advances in high-throughput nucleic acid sequencing and massive computerized analysis, the field has now taken a quantum leap further to sequence transcribed RNA to detect abnormalities.⁵

The techniques are straightforward: RNA is isolated and reverse transcribed to complementary DNA. The complementary DNA is amplified and then processed by high-throughput sequencers. The sequences are then identified by computer algorithms. It is possible to fully define the transcriptomes of multiple genes, even reaching the threshold of resolution of gene expression emanating from a single cell.⁶

Studying Gene Expression for Malignant Melanoma

As much as we rely on visual interpretations, we acknowledge that many conditions look very similar, whether to the naked eye or under the microscope. This is true for rare diseases but also for the rashes we routinely see. A group of investigators recently used RNA transcriptome sequencing to analyze differences between atopic dermatitis and psoriasis, permitting better differentiation of these 2 common conditions.⁷

One of the greatest challenges confronting dermatologists and their dermatopathologist partners is to distinguish malignant melanoma from benign nevi.⁸ Despite staining for a number of molecular markers, some lesions defy histopathology, such as distinguishing benign and malignant Spitz nevi; however, recent work on RNA transcriptomes suggests that gene expression may increase confidence in assessing atypical Spitz nevi.⁹ A 23-gene expression panel has yielded a sensitivity of 91.5% and a specificity of 92.5% in differentiating benign nevi from malignant melanoma.¹⁰

From the Research Laboratory to Routine Clinical Use

Undoubtedly, it is a large step from proof-of-concept studies to accepted clinical use. The ultimate achievement for a laboratory technique is to enter approved clinical use. Gene expression panels have now been approved by numerous third-party insurers to help predict future clinical evolution of biopsied melanomas. Although early in situ melanomas are eminently curable by wide excision, lesions that have more concerning characteristics (eg, depth >0.8 mm, ulceration) may progress to metastatic disease. The gratifying success of checkpoint inhibitor therapy has improved the previously dismal outlook for advanced melanomas.¹¹ Dermatologists search for clues to suggest which patients may benefit from adjuvant therapy. Sentinel lymph node biopsy (SLNB) has been a standard-of-care technique to help make this determination.¹²

It has now been demonstrated that gene expression array analysis can provide evidence complementing SLNB results or even independent of SLNB results. In extensive validation studies, a 31-gene expression panel analyzing initial melanoma biopsy specimens showed predictive value for later recurrence and development of metastatic disease.^13,14 The gene expression studies have identified patients with negative SLNBs who have gone on to develop metastatic melanomas.¹⁵ It has been suggested that gene expression panel diagnosis may reduce the need for invasive SLNBs in patients in whom the surgical procedure may involve risk.¹⁶

Looking to the Future

The progress of science is the result of many small steps building on prior work. The terms breakthrough and game changer in medicine have been popularized by the media and rarely are valid. On the contrary, sequential development of methods over many years has preceded the acclaimed successes of medical research; for example, the best-known medical breakthrough—that of Salk’s inactivated polio vaccine—was preceded by the use of an inactivated polio vaccine by Brodie and Park¹⁷ in 1935. However, it was the development of tissue culture of poliomyelitis virus by Enders et al¹⁸ that provided the methodology to Salk’s group to produce their inactivated polio vaccine.

The ability to go beyond our visual senses will be of great importance in characterizing the variability of skin diseases, especially in skin of color patients; for example, acral melanoma is perhaps the primary melanocytic malignancy in darker-skinned patients and is the target of RNA transcriptomic research.¹⁹ Progress is continuing on gene therapy for a growing number of skin conditions.^20,21 In vivo correction of abnormal genes is being attempted for a number of inherited cutaneous diseases,²² notably for disorders of skin fragility.²³ For now, we welcome the addition of genomic capabilities to the visual practice of dermatology and the capability to go beyond that which we can see with our eyes.