Immunohistochemical characteristics of breast-carcinoma in patients receiving neuroleptic therapy.

The immunohistochemical characteristics of 17 cases of breast carcinoma in patients treated with neuroleptics (prolactin-releasing drug) are reported. Sixteen of the patients were female and one was male. Sixteen tumors in thirteen patients were invasive ductal carcinoma, two tumors in two patients were lipid-secreting carcinoma, one tumor was apocrine carcinoma, and two tumors in one patient were mucinous carcinoma. Elevated serum prolactin (Prl) levels (>15.0 ng/ml) were seen in all 7 patients whose preoperative serum prolactin levels had been determined. Immunohistochemical staining showed that 71% (15/21) of the carcinomas reacted positively for prolactin receptor (PrlR), while immunoreactive Prl was totally negative. Fourteen tumors were estrogen receptor (ER)-positive (67%; 14/21), and 12 were progesterone receptor (PgR)-positive (57%; 12/21). These results suggest that Prl secreted from the pituitary gland may interact with PrlR present on the cancer cells, but there was no evidence of de novo synthesis or uptake of Prl by cancer cells. ER and PgR status showed no characteristic immunoreactivity compared with unselected breast carcinoma patients not related to neuroleptic use.