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A form of the CYP3A7 gene is associated with poor outcomes in chronic lymphocytic leukemia (CLL) and other cancers, according to a study published in Cancer Research.
Among patients with CLL, breast cancer, or lung cancer, those with the CYP3A7*1C allele were more likely than those without it to experience disease progression or death.
Researchers believe this may be related to how patients metabolize treatment.
“The CYP3A7 gene encodes an enzyme that breaks down all sorts of naturally occurring substances—such as sex steroids like estrogen and testosterone—as well as a wide range of drugs that are used in the treatment of cancer,” said Olivia Fletcher, PhD, of The Institute of Cancer Research in London, UK.
“The CYP3A7 gene is normally turned on in an embryo and then turned off shortly after a baby is born, but individuals who have 1 or more copies of the CYP3A7*1C form of the gene turn on their CYP3A7 gene in adult life.”
“We found that individuals with breast cancer, lung cancer, or CLL who carry 1 or more copies of the CYP3A7*1C allele tend to have worse outcomes. One possibility is that these patients break down the drugs that they are given to treat their cancer too fast. However, further independent studies that replicate our findings in larger numbers of patients and rule out biases are needed before we could recommend any changes to the treatment that cancer patients with the CYP3A7*1C allele receive.”
To assess the impact of the CYP3A7*1C allele on patient outcomes, Dr Fletcher and her colleagues analyzed DNA samples from 1008 breast cancer patients, 1142 patients with lung cancer, and 356 patients with CLL.
The team looked for the presence of the single nucleotide polymorphism (SNP) rs45446698. Dr Fletcher explained that rs45446698 is 1 of 7 SNPs that cluster together to form the CYP3A7*1C allele.
The researchers found that, among CLL patients, rs45446698 (and, therefore, the CYP3A7*1C allele) was associated with a 62% increased risk of disease progression (P=0.03).
Among breast cancer patients, rs45446698 was associated with a 74% increased risk of breast cancer mortality (P=0.03). And among the lung cancer patients, the SNP was associated with a 43% increased risk of death from any cause (P=0.009).
The researchers also found borderline evidence of a statistical interaction between the CYP3A7*1C allele, treatment of patients with a cytotoxic agent that is a CYP3A substrate, and clinical outcome (P=0.06).
“Even though we did not see a statistically significant difference when stratifying patients by treatment with a CYP3A7 substrate, the fact that we see the same effect in 3 very different cancer types suggests to me that it is more likely to be something to do with treatment than the disease itself,” Dr Fletcher said.
“However, we are looking at ways of replicating these results in additional cohorts of patients and types of cancer, as well as overcoming the limitations of this study.”
Dr Fletcher explained that the main limitation of this study is that the researchers used samples and clinical information collected for other studies. So they did not have the same clinical information for each patient, and the samples were collected at different time points and for patients treated with various drugs.
She also noted that the researchers were not able to determine how quickly the patients broke down their treatments.
This study was supported by Sanofi-Aventis, Breast Cancer Now, Bloodwise, Cancer Research UK, the Medical Research Council, the Cridlan Trust, and the Helen Rollason Cancer Charity. The authors’ institutions received funding from the National Health Service of the United Kingdom. 
A form of the CYP3A7 gene is associated with poor outcomes in chronic lymphocytic leukemia (CLL) and other cancers, according to a study published in Cancer Research.
Among patients with CLL, breast cancer, or lung cancer, those with the CYP3A7*1C allele were more likely than those without it to experience disease progression or death.
Researchers believe this may be related to how patients metabolize treatment.
“The CYP3A7 gene encodes an enzyme that breaks down all sorts of naturally occurring substances—such as sex steroids like estrogen and testosterone—as well as a wide range of drugs that are used in the treatment of cancer,” said Olivia Fletcher, PhD, of The Institute of Cancer Research in London, UK.
“The CYP3A7 gene is normally turned on in an embryo and then turned off shortly after a baby is born, but individuals who have 1 or more copies of the CYP3A7*1C form of the gene turn on their CYP3A7 gene in adult life.”
“We found that individuals with breast cancer, lung cancer, or CLL who carry 1 or more copies of the CYP3A7*1C allele tend to have worse outcomes. One possibility is that these patients break down the drugs that they are given to treat their cancer too fast. However, further independent studies that replicate our findings in larger numbers of patients and rule out biases are needed before we could recommend any changes to the treatment that cancer patients with the CYP3A7*1C allele receive.”
To assess the impact of the CYP3A7*1C allele on patient outcomes, Dr Fletcher and her colleagues analyzed DNA samples from 1008 breast cancer patients, 1142 patients with lung cancer, and 356 patients with CLL.
The team looked for the presence of the single nucleotide polymorphism (SNP) rs45446698. Dr Fletcher explained that rs45446698 is 1 of 7 SNPs that cluster together to form the CYP3A7*1C allele.
The researchers found that, among CLL patients, rs45446698 (and, therefore, the CYP3A7*1C allele) was associated with a 62% increased risk of disease progression (P=0.03).
Among breast cancer patients, rs45446698 was associated with a 74% increased risk of breast cancer mortality (P=0.03). And among the lung cancer patients, the SNP was associated with a 43% increased risk of death from any cause (P=0.009).
The researchers also found borderline evidence of a statistical interaction between the CYP3A7*1C allele, treatment of patients with a cytotoxic agent that is a CYP3A substrate, and clinical outcome (P=0.06).
“Even though we did not see a statistically significant difference when stratifying patients by treatment with a CYP3A7 substrate, the fact that we see the same effect in 3 very different cancer types suggests to me that it is more likely to be something to do with treatment than the disease itself,” Dr Fletcher said.
“However, we are looking at ways of replicating these results in additional cohorts of patients and types of cancer, as well as overcoming the limitations of this study.”
Dr Fletcher explained that the main limitation of this study is that the researchers used samples and clinical information collected for other studies. So they did not have the same clinical information for each patient, and the samples were collected at different time points and for patients treated with various drugs.
She also noted that the researchers were not able to determine how quickly the patients broke down their treatments.
This study was supported by Sanofi-Aventis, Breast Cancer Now, Bloodwise, Cancer Research UK, the Medical Research Council, the Cridlan Trust, and the Helen Rollason Cancer Charity. The authors’ institutions received funding from the National Health Service of the United Kingdom.
A form of the CYP3A7 gene is associated with poor outcomes in chronic lymphocytic leukemia (CLL) and other cancers, according to a study published in Cancer Research.
Among patients with CLL, breast cancer, or lung cancer, those with the CYP3A7*1C allele were more likely than those without it to experience disease progression or death.
Researchers believe this may be related to how patients metabolize treatment.
“The CYP3A7 gene encodes an enzyme that breaks down all sorts of naturally occurring substances—such as sex steroids like estrogen and testosterone—as well as a wide range of drugs that are used in the treatment of cancer,” said Olivia Fletcher, PhD, of The Institute of Cancer Research in London, UK.
“The CYP3A7 gene is normally turned on in an embryo and then turned off shortly after a baby is born, but individuals who have 1 or more copies of the CYP3A7*1C form of the gene turn on their CYP3A7 gene in adult life.”
“We found that individuals with breast cancer, lung cancer, or CLL who carry 1 or more copies of the CYP3A7*1C allele tend to have worse outcomes. One possibility is that these patients break down the drugs that they are given to treat their cancer too fast. However, further independent studies that replicate our findings in larger numbers of patients and rule out biases are needed before we could recommend any changes to the treatment that cancer patients with the CYP3A7*1C allele receive.”
To assess the impact of the CYP3A7*1C allele on patient outcomes, Dr Fletcher and her colleagues analyzed DNA samples from 1008 breast cancer patients, 1142 patients with lung cancer, and 356 patients with CLL.
The team looked for the presence of the single nucleotide polymorphism (SNP) rs45446698. Dr Fletcher explained that rs45446698 is 1 of 7 SNPs that cluster together to form the CYP3A7*1C allele.
The researchers found that, among CLL patients, rs45446698 (and, therefore, the CYP3A7*1C allele) was associated with a 62% increased risk of disease progression (P=0.03).
Among breast cancer patients, rs45446698 was associated with a 74% increased risk of breast cancer mortality (P=0.03). And among the lung cancer patients, the SNP was associated with a 43% increased risk of death from any cause (P=0.009).
The researchers also found borderline evidence of a statistical interaction between the CYP3A7*1C allele, treatment of patients with a cytotoxic agent that is a CYP3A substrate, and clinical outcome (P=0.06).
“Even though we did not see a statistically significant difference when stratifying patients by treatment with a CYP3A7 substrate, the fact that we see the same effect in 3 very different cancer types suggests to me that it is more likely to be something to do with treatment than the disease itself,” Dr Fletcher said.
“However, we are looking at ways of replicating these results in additional cohorts of patients and types of cancer, as well as overcoming the limitations of this study.”
Dr Fletcher explained that the main limitation of this study is that the researchers used samples and clinical information collected for other studies. So they did not have the same clinical information for each patient, and the samples were collected at different time points and for patients treated with various drugs.
She also noted that the researchers were not able to determine how quickly the patients broke down their treatments.
This study was supported by Sanofi-Aventis, Breast Cancer Now, Bloodwise, Cancer Research UK, the Medical Research Council, the Cridlan Trust, and the Helen Rollason Cancer Charity. The authors’ institutions received funding from the National Health Service of the United Kingdom.