GSTM1 and neoplasm: In multivariate analysis, patients with T3 or T4 tumor, FAS c.-671GG, GSTM1 present plus XPC c.2815AA, GSTM1 present plus XPD c.934GG, GSTM1 present plus XPD c.2251AA, GSTM1 present plus XPF c.2505TT, GSTM1 present plus TP53 c.215CC or GC, GSTM1 present plus CASP3 c.-1191GG or AG, XPD c.2251AA plus XPF c.2505TT, and ERCC1 c.354TT plus FASL c.-844CC had up to 2.69 times more chances of presenting progression, relapse, or death by disease effects than others.