Tumor specimens were histologically and immunohistochemical examined: anterior pituitary hormones, ki-67 labeling index, CAM 5.2, and ER∝; ER∝ expression was correlated with basal PRL levels at diagnosis (rho = 0.60, <i>p</i> < 0.01) and postoperative PRL levels (rho = 0.58, <i>p</i> < 0.001). The gene discussed is PRL; the disease is neoplasm.