CYP1A1 and CYP3A4 polymorphic variations in Delhi population of Northern India.

Cytochrome P450 (CYP) 1A1 and CYP3A4 are important phase I xenobiotic metabolizing enzymes involved in the metabolism of numbers of toxins, endogenous hormones and pharmaceutical drugs. Polymorphisms in these phase I genes can alter enzyme activity and are known to be associated with cancer susceptibility related to environmental toxins and hormone exposure. Their genotypes may also display ethnicity dependent population frequencies. The present study was aimed to determine the frequencies of commonly known functional polymorphisms of CYP1A1 and CYP3A4 in North Indian population. Allelic frequency of CYP1A1 polymorphisms, m1, m2 and m4 were observed to be 40.3, 31.2 and 0% respectively. Frequency of CYP3A4*1B polymorphism was 0%. We observed inter as well as intra ethnic variation in the distribution of frequency of these polymorphisms. Analysis of polymorphisms in these genes might help in predicting the risk of cancer. Our results emphasize the need for more such studies in "high risk populations".