TNFRSF11A and breast cancer: discovered two luminal progenitor subgroups, the receptor of inhibit tumor necrosis factor superfamily member 11(RANK)(+) and RANK(-), in normal tissue of individuals susceptible to breast cancer due to breast cancer susceptibility gene1(BRCA1) mutations, where RANK(+) cells exhibited high proliferative capacity, severe DNA repair abnormalities, and molecular characteristics similar to basal-like breast cancer.