GSTM1 and cancer: Indeed, there are reports indicating that GSTM1 is linked to GSTM3 (Inskip et al, 1995) and GSTP1 (Maugard et al, 2001), and thus the effect of GSTM1 on cancer susceptibility may be influenced by the expression of GSTP1 and/or GSTM3, suggesting that interactions between GST genes may be a significant factor in determining cancer susceptibility.