A great number of studies have shown that cytochrome P450 1A1 (CYP1A1) genetic polymorphisms, CYP1A1 Msp I and CYP1A1 Ile/Val, might be risk factors for digestive tract cancers, including esophageal cancer (EC), gastric cancer (GC), hepatic carcinoma (HC), as well as colorectal cancer (CC), but the results are controversial.
Our results suggest that the I462V and Msp1 polymorphisms in CYP1A1 may be an additional susceptibility factor for disease expression in Lynch syndrome because they modify the age of colorectal cancer onset by up to 4 years.
A positive association between development of colorectal cancer and the mutant homozygous genotype in Msp1 polymorphism of CYP1A1 gene has been reported in Japanese in Hawaii.
The protective effect of the 16 bp duplication was more pronounced in haplotype combinations with the BstU I A1 and Msp I A1 alleles, whereas these alleles in combination with the 16 bp A1 allele (no duplication) were associated with an increased risk for colorectal cancer.