Gene coding for the glutathione S-transferase M1 (GSTM1) functions in the detoxification of electrophilic compounds, including carcinogens, therapeutic drugs, environmental toxins and the bioactivation of a variety of xenobiotics present in food, organic solvents, tobacco smoke, drugs, pesticides, alcoholic drinks. There was evidence indicate that GSTM1 expressed along the human gastrointestinal tract. The null genotype of this GST gene affected to the capability to tolerate a given chemical class and associated with higher risk of cancer. In this study the frequency of GSTM1 was determined in 81 Vietnamese patients with colorectal adenocarcinoma and compared to frequencies determined in 85 patients of non-cancer control group. The frequency of the null GSTM1 genotype in patients with colorectal adenocarcinoma cases (75.3 percent) compared to the control group frequency (69.4 percent) (odds ratio (OR) = 1.70
95 percent CI, 1.052.76). The frequency of the GSTM1 genotype in patients with colorectal adenocarcinoma cases (24.7 percent) compared to the control group frequency (30.6 percent) (odds ratio (OR) = 1.34
95 percent CI, 0.67-3.66). These results suggest that the GSTM1 null genotype may not be associated with susceptibility to colorectal adenocarcinoma in Vietnamese
however, additional studies will be needed to confirm these findings.