MRC1 and cancer: Cumulative lifetime risks for other Lynch syndrome cancers are even more uncertain, but estimates generally do not exceed 15%.46,48,49,50,51 Some, but not all, of the variation is accounted for by different risk profiles for different MMR gene mutations: in general, risks for MLH1 or MSH2 carriers are higher, and age at onset of disease lower, than for those with mutations in MSH6 or PMS2. 52,53