Leu432Val Polymorphism of CYP1B1 is Not Associated with Squamous Cell Carcinoma of Esophagus - a Case-Control Study from Kashmir, India


Background: Individual susceptibility to cancer has been attributed to polymorphisms in xenobioticmetabolizing genes. To evaluate the association of the Leu432Val polymorphism of cytochrome P4501B1 (CYP1B1)with esophageal squamous cell carcinoma (ESCC), we conducted a case control study in Kashmir, India, an areawith a relatively high incidence of ESCC. Materials and
Methods: We recruited 404 histopathologically confirmedESCC cases, and an equal number of controls, individually matched for sex, age and district of residence torespective cases. Information was obtained on various dietary, lifestyle and environmental factors in face to faceinterviews, using a structured questionnaire, from each subject. Genotypes were analysed by polymerase chainreaction, restriction fragment length polymorphism and sequencing of randomly selected samples. Conditionallogistic regression models were used to calculate odds ratios (ORs) and 95% confidence intervals (95% CIs).
Results: Among the three possible variants, we did not find any Leu432Leu genotype of CYP1B1 in the studypopulation and the genotypic distribution of Val432Val and Leu432Val carriers was nearly equal in both cases(89.6% and 10.4%) and controls (88.9% and 11.1%) respectively. We did not find any risk associated with thispolymorphism in the current study (OR = 0.64; 95% CI: 0.55 – 1.64).
Conclusions: The study indicates that(Leu432Val) polymorphism of CYP1B1, is not associated with ESCC risk. However, replicative studies withlarger sample size are needed to substantiate the findings.