Another study involving 1,400 patients revealed that prolactin was associated with the occurrence of breast cancer, especially in postmenopausal women (relative risk: 1.37, p < 0.05) and in patients with ER + status (relative risk: 1.28, 95% confidence interval: 1.07–1.54, p = 0.003) [9]. This evidence concerns the gene PRL and breast carcinoma.