GSTM1 and cancer: The genes of the GSTM family are arranged in an alignment of the 5′‐GSTM4‐M2‐M1‐M5‐M3‐3′ sequence.4 The GSTM1 gene is localized on chromosome 1p13, and the GSTM1‐null genotype seems to be susceptible to many cancers as breast, lung, and colon cancers.