GSTP1 and chromophobe renal cell carcinoma: Although GSTM1-null genotype did not, at least independently, significantly affect the risk of cRCC in smokers (OR = 1.71, 95%CI:0.95–3.06, p = 0.07), when present in combination with GSTP1-variant genotype, it contributed in a way that smokers with GSTM1-null/GSTP1-variant genotype exhibited 5.4–fold increased risk of cRCC (95%CI:1.74–16.98, p = 0.004) in comparison with carriers of GSTM1-active/GSTP1 wild-type genotype.