Glutathione transferases, broccoli, and colon adenomas

Our interest is to use an epidemiologic approach to study how cruciferous vegetables may prevent colorectal adenomas, which are precursors to cancer. Broccoli contains the compound, sulforaphane, an isothiocyanate that induces carcinogen-detoxifying enzymes. Isothiocyanates are conjugated by glutathione transferase enzymes, leading to excretion. In an earlier case-control study, we observed the lowest prevalence of colorectal adenomas among subjects with high broccoli intake and the GSTM1 null genotype. Here we extend the analysis to a genetic variant of GSTP1.