MRC1 and breast cancer: It included two TP53 pedigrees that did not fulfill Chompret criteria (Figure 2A1 and 2C1); four MMR mutations, in two patients with single-affected early-onset BC, one patient with familial BC, and one patient with BC but a family history of two endometrial cancers, which could have led to MMR testing in the relatives (Figure 2B1, B2, B3, C3), with a negative search for microsatellite instability in three breast tumors with available material.