PRLR and prostate cancer: Prolactin receptor (PRLR), which has been suggested as a therapeutic target in subgroups of breast and of prostate cancer [27], was overexpressed in EGFR-positive tumors compared to ALK/EGFR-negative tumors and compared to ALK-positive tumors (FC = 3.8, p = 0.0004 and FC = 2.6, p = 0.013).