The patterns of two-hit inactivation of the predisposing MMR genes in LS-BC closely resembled those previously observed for LS-OC and LS-CRC, where a detectable second hit, mostly LOH, was present in 10/16 (63%) of LS-OCs and 15/18 (83%) of LS-CRCs (Table 2 and ref [15]). The gene discussed is MRC1; the disease is colorectal carcinoma.