CRC mortality declined by 8.8% after 7 years of implementing biennial FIT screening (cut-off 20 μg Hb/g) in Spain [10] and a reduction of 52% was observed after 16 years of annual FIT screening (cut-off 20 μg Hb/g) in northern California (US) [12], while no significant reduction was observed after 6 years of biennial FIT screening (cut-off 47 μg Hb/g) in the Netherlands [11]. The gene discussed is GSTM1; the disease is colorectal carcinoma.