Cytochrome P450 1A1 (CYP1A1) is gene that encoding for enzymes belong to Cytochrome P450 family which involve in metabolic processes of xenobiotic. In phase I of this process, CYP1A1 realate to metabolism of carcinogenic substance. previous studies showed that the relationship between the gene polymorphism of CYP1A1 properties with certain types of cancer such as: colorectal cancer, stomach cancer, breast cancer, ... in which mainly are CYP1A1*2A, CYP1A1*2B, CYP1A1*4 genotype. Study on 166 objects include 85 in cotrol group and 81 objects to be diagnosed with colorectal cancer at 3 hospitals: Bach Mai Hospital, Vietnam National Cancer Hospital, Viet Duc Hospital not limited to age, sex. The results indicate that: the ratio of the CYP1A1*2B genotype in control groups is 5.9 percent A/A, 87.1 percent A/G and 7.0 percent G/G, in response
in colorectal cancer group is 6.2 percent of A/A, 87.7 percent A/G and 6.1 percent G/G. There is no relationship between CYP1A1*2B genotype and colorectal cancer.