GSTM1 and colorectal cancer: Inclusion of SPECC lesions did not alter the significance of this comparison of laterality, with right colorectal cancers and SPECC demonstrating lower median fHb levels (61·2 (i.q.r. 15·8–403·4) versus 329·7 (71·8–1705·0) μg Hb/g faeces; P = 0·027).