GLUTATHIONE-S-TRANSFERASE GSTT1 GENOTYPES AND SUSCEPTIBILITY TO CANCER - STUDIES OF INTERACTIONS WITH GSTM1 IN LUNG, ORAL, GASTRIC AND COLORECTAL CANCERS

Allelism in glutathione S-transferase GSTM1 and GSTT1 has been suggest ed as a risk factor in various cancers, Accordingly, we describe a gro up of case-control studies carried out to identify associations betwee n GSTT1 genotypes and susceptibility to lung, oral, gastric and colore ctal cancers, The frequencies of the putatively high risk GSTT1 null g enotype were not increased in the lung, oral or gastric cancer cases c ompared with controls but the frequency of this genotype was significa ntly increased (P = 0.0011, odds ratio = 1.88) in the colorectal cance r cases, No significant interactions between the GSTT1 and GSTM1 null genotypes were identified in the cancer groups studied, Indeed, no sig nificant associations between GSTM1 genotypes and susceptibility were identified though further evidence was obtained that the protective ef fect of GSTM1A and GSTM1*B is not equal, The data complement studies showing that GSTT1 null is associated with an increased susceptibility to total ulcerative colitis and suggests that this enzyme is importan t in the detoxification of unidentified xenobiotics in the large intes tine.