Deletion polymorphisms in the genes GSTM1 and GSTT1 and a base transition polymorphism at codon 105 (Ile-->Val) in GSTP1 were investigated in relation to breast cancer risk.
Trends in the association between urinary ITC and breast cancer were more consistent with homozygous deletion of GSTM1 or GSTT1, the AAgenotype of GSTP1 (A313G), or with the C allele of NADPH quinine oxidoreductase (C609T), although interactions were not statistically significant.
When COMT(LL) was combined with either glutathione S-transferase (GST) M1 null or with GSTP1 Ile-105-Val/Val-105-Val (intermediate/low activity, respectively) genotypes, the risk for developing postmenopausal breast cancer was also significantly increased.