GSTM1 and colorectal carcinoma: Two very recent papers from the Netherlands clearly demonstrate how for those with a negative screening test result, f-Hb results closest to the threshold for positivity showed a strong association with future diagnoses of CRC both as interval cancers7 (IC: CRC diagnosed in the interval between screening invites following a negative screening test result) or in subsequent screening rounds,8 compared with very low or undetectable f-Hb.