GSTM1 and colorectal carcinoma: Prior research indicates that quantitative f-Hb concentrations are positively associated with the future detection of advanced adenomas and CRC, also among those with a negative FIT (Digby et al., 2017; Kooyker et al., 2020; Senore et al., 2020; Buron et al., 2019; van den Berg et al., 2025).