Eighty-five publications involving eighty-six case–control studies [14–17,19–24,26–36,38–42,44–60,62–64,66–78,80–83,85,87,88,90,91,93,96–99,101,103–107,108,109,111–114] were included on the GSTM1 present/null polymorphism (24,931 cases and 36,537 controls; 44 studies on Caucasians, 31 on Asians, one on Africans, one on Indians, and nine on mixed populations) with CRC risk. The gene discussed is GSTM1; the disease is colorectal carcinoma.