GSTM1 and colorectal carcinoma: The aim of our study was to replicate these findings on a smaller, highly homogeneous cohort [11] of CRC patients, that is, to determine whether common genetic polymorphisms in the most important isoenzymes of the GST,  family (GSTA, GSTM1, GSTP1,  and GSTT1) predispose to the development of CRC cancer in this model population.