GSTM1 and colorectal carcinoma: The examination of 44 studies of GSTM1 (11,998 CRC cases and 17,552 controls) and 34 studies of GSTT1 (8596 CRC cases and 13,589 controls) by Economopoulos and Sergentanis [122] indicated that the GSTM1 and GSTT1 null genotypes were associated with an increased CRC risk in Caucasians.