GSTM1 is produced in the liver. Through conjugation with glutathione, it functions in the detoxification of environmental toxins and products of oxidative stress, electrophilic compounds, including carcinogens and therapeutic drugs.
Individuals with the GSTM1 */0 Genotype do not have this functioning enzymes and are at greater risk to develop carcinomas.
GSTT1 is found in lymphocytes and the liver, and is involved in the detoxification process of a variety of environmental chemicals, such as the ones used in polymer productions. Like all GST Enzymes, GSTT1 detoxifies cancer-causing chemicals as found in cigarette smoke. Approximately 38% of Caucasians show a complete lack of GTT1 activity. This group with the GSTT1 */0 Genotyp shows a high risk for carcinoma of the lung, breast and larynx.
GSTP1 is build in blood lymphocytes and tissues such as prostate, lung, breast and brain. It plays an important role in detoxification by catalyzing the conjugation of many hydrophobic and electrophilic compounds with reduced glutathione.
About 50% of the Caucasian population shows complete loss of function, which aids the accumulation of reactive products and thus increases the risk of cancer and neurological diseases.
The NAT2 functions to both activate and deactivate arylamine and hydrazine drugs and carcinogens. Polymorphisms in this gene are responsible for the N-acetylation process in which humans are segregated into rapid, intermediate or slow acetylator phenotypes.
Lack of NAT2 function is associated with higher incidences of cancer and drug toxicity. Rapid acetylators have a higher risk for colorectal cancer. (Osian G., Procopciuc L, Vlad L. Nat2 gene polymorphism and sporadic colorectal cancer. Prevalence, tumor stage and prognosis. J.Gastrointestin Liver Dis. 2006; 15(4):357-53)