MUTYH and adenoma: We profiled four adenomas and a CRC from Pat_763 who carried a germline heterozygous pathogenic variant (c.1187G>A p.(Gly396Asp)) and a germline heterozygous VUS (c.533G>C p.(Gly178Ala)) in MUTYH. All four adenomas (mean proportion: 73.0 %±14.9 %, range: 57.3 %−88.0 %) and the CRC (72.7 %) demonstrated high proportions of SBS18+SBS36 consistent with germline biallelic inactivation of MUTYH (Figs. 2A andFig. 3).