Figure 1

RANKL/RANK signaling in breast cancer. Mammary carcinogenesis driven by BRCA1 mutations relies on autocrine or paracrine RANKL/RANK signaling in mammary progenitor cells. Breast cancers developing as a consequence of BRCA1 mutations also depend on progesterone signaling (knowing that progesterone derivatives also promote mammary carcinogenesis), most likely as a result of progesterone receptor-driven RANKL expression and consequent proliferation of mammary progenitor cells. The mechanisms linking the accumulation of genetic defects to carcinogenesis via the RANKL/RANK system, as well as the possible impact of RANKL/RANK signaling in the mammary epithelium on anticancer immunosurveillance remain to be determined.