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CYP2A6 gene deletion reduces susceptibility to lung cancer
M Miyamoto1, Y Umetsu, H Dosaka-Akita
1Graduate School of Pharmaceutical Sciences, Hokkaido University, Sapporo, 060-0812, Japan.
Abstract:
CYP2A6 is an enzyme with a high ability to activate a nitrosamine, 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), to its potent and ultimate carcinogen. In the present study, we investigated the relationship between genetic polymorphism of CYP2A6 and lung cancer risk in a case-control study of Japanese subjects. Genotyping of the CYP2A6 gene in both healthy volunteers and lung cancer patients was conducted. The frequency with which the subjects carried homozygotes of the CYP2A6 gene deletion-type mutation (deletion), which causes lack of the enzyme activity, was lower in the lung cancer patients than in the healthy control subjects. The odds ratio (OR) of the group homozygous for the deletion was significantly lower and calculated to be 0.25 (95% CI; 0.08-0.83) when the OR for the population with homozygotes of the CYP2A6 wild-type gene was defined as 1.00. In the allelic-base analysis, there was also a significant decrease in the OR for the deletion allele. These data suggest that deficient CYP2A6 activity due to genetic polymorphism reduces lung cancer risk.
Insights
Genetic variations in the CYP2A6 enzyme, which activates carcinogens like NNK, may reduce lung cancer risk. Individuals with a CYP2A6 gene deletion showed a significantly lower risk, suggesting a protective effect.
Area of Science:
- Biochemistry
- Genetics
- Oncology
Background:
- Cytochrome P450 2A6 (CYP2A6) is a key enzyme involved in metabolizing various xenobiotics.
- CYP2A6 activates procarcinogens, such as 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK), into ultimate carcinogens implicated in lung cancer.
- Genetic polymorphisms in CYP2A6 can lead to variations in enzyme activity, potentially influencing individual susceptibility to cancer.
Purpose of the Study:
- To investigate the association between CYP2A6 genetic polymorphisms and lung cancer risk in a Japanese population.
- To determine if specific CYP2A6 genotypes, particularly those affecting enzyme activity, are linked to differential lung cancer susceptibility.
Main Methods:
- A case-control study was conducted involving Japanese lung cancer patients and healthy control subjects.
- Genotyping of the CYP2A6 gene was performed for all participants.
- Statistical analysis, including odds ratio (OR) calculations, was used to assess the relationship between CYP2A6 genotypes and lung cancer risk.
Main Results:
- The frequency of homozygotes for the CYP2A6 gene deletion-type mutation (which results in no enzyme activity) was lower in lung cancer patients compared to healthy controls.
- The odds ratio for individuals homozygous for the CYP2A6 deletion was significantly reduced (OR = 0.25; 95% CI: 0.08-0.83) compared to those with the wild-type gene.
- Allele-based analysis also revealed a significant decrease in the odds ratio for the deletion allele, indicating a protective effect.
Conclusions:
- Deficient CYP2A6 enzyme activity, resulting from genetic polymorphism, appears to reduce the risk of developing lung cancer.
- These findings highlight the role of CYP2A6 genetic variations in modulating individual susceptibility to NNK-induced lung carcinogenesis.
- Targeting CYP2A6 activity or understanding its genetic influence could have implications for lung cancer prevention strategies.