GSTM1 and neoplasm: Senore et al. [41] demonstrated that in a population-wide screening program of average-risk individuals, a combined undetectable fecal Hb from multiple previous rounds of FIT (about 50% of the participants) led to a 1.4% risk of finding an advanced neoplasia over the subsequent two rounds of colonoscopy compared to those with a FIT Hb level ≥ 20 μg/g (about 0.7% of the population) who had an 18-fold increase in their cumulative advanced neoplasia risk over the same time interval [41].