GSTM1 and adenocarcinoma: Indeed, data from Scotland have shown that sex differences in median f-Hb persisted when compared at all CRC sites.17 ICs are also associated with the serrated pathway of carcinogenesis.22,24 Sessile serrated lesions occur more often in the proximal colon, and bleed less than adenocarcinoma and are therefore less likely to trigger a positive FOBT; these characteristics may contribute to some of the gender inequality in CRC detection using FOBT screening.