PRLR (Prolactin Receptor): PRLR is a receptor that binds to the hormone prolactin, which is involved in milk production, reproductive functions, and immune regulation. Upon prolactin binding, PRLR activates signaling pathways that regulate cell growth, development, and differentiation. Dysregulation of PRLR signaling has been linked to breast and other cancers, emphasizing its role in cellular proliferation and its potential as a therapeutic target.