CYP1A1 Msp1 T/C polymorphism in esophageal cancer: no association and risk modulation.

Phase I enzyme CYP1A1 metabolizes environmental carcinogens and a Msp1 T/C functional polymorphism in 3'UTR in its gene has been reported to influence the inducibilty of the enzyme. There are controversies regarding association of the polymorphism with risk of esophageal cancer in Chinese and Caucasian populations. Moreover, no study has been done in Indian populations. The present study was aimed to explore the associations of CYP1A1 3'UTR polymorphism with clinical phenotypes and environmental interaction in esophageal cancer from North Indian population. A total of age- and gender-matched 161 cases and 201 healthy controls were used to genotype the CYP1A1 3'UTR polymorphism by PCR-EFLP methodology. None of the CYP1A1 genotypes and alleles was significantly associated with risk of esophageal cancer, even after adjusting for age and sex. After stratifying the genotypes according to disease characteristics such as tumor histology, location, and lymph nodes, individuals with TT genotype were at high risk for developing tumor in the upper third location (OR: 2.2, 95% CI: 0.81-6.2, p = 0.11). Interaction of tobacco usage (smoking or nonsmoking) and presence of occupational exposure in esophageal cancer patients did not show significant increase in cancer risk with CYP1A1 genotypes. However, in patients with alcohol habits, TT genotype showed a higher risk, which was not significant (OR: 2.5, 95% CI: 0.61-10.6, p = 0.19). In conclusion, CYP1A1 genotype did not influence the susceptibility of developing esophageal cancer. The presence of variant CYP1A1 genotypes together with environmental exposures also did not modulate the cancer risk.