ERBB2 and posterior cortical atrophy: Although the function of PRL and PRLR in PCa is not yet fully understood, previous studies have established STAT5 as a vital downstream mediator of PRLR [22, 40], and other downstream pathways, such as Src family kinases, phosphatidylinositol-3-phosphate kinase/Akt, TEC, NEK3 and EGFR/HER2, are also regulated by PRLR [41, 42].