Immunohistochemical study on the expression of parathyroid hormone-related protein in ovarian tumors

Abstract

Expression of parathyroid hormone-related protein (PTHrP), which may cause humoral hypercalcemia associated with malignancy, has been investigated in lung, mammary, renal and other cancers. There are a few reports of such studies in ovarian cancers. We have carried out the immunohistochemical (ABC staining) study on the PTHrP expression using a specific anti PTHrP antibody, 4B3, in formalin-fixed, paraffin-embedded sections of 28 various ovarian tumors: 2 serous cystadenomas, 5 serous cystadenocarcinomas, 2 mucinous cystadenomas, 2 mucinous cystadenocarcinomas, 4 endometrioid adenocarcinomas, 5 clear cell adenocarcinomas, 1 dysgerminoma, 3 yolk sac tumors, 2 mature teratomas, and 2 mature teratomas, and 2 immature teratomas. Immunohistochemical criteria for PTHrP expression were: (−), totally negative; (±), positive in ≦10% tumor cells; (+), positive in 10∼50% tumor cells; (++), positive in ≧50% tumor cells. Results indicated positive staining in 4 of 5 serous cystadenocarcinomas, 2 of 4 endometrioid adenocarcinomas, 5 of 5 clear cell adenocarcinomas, 3 of 3 yolk sac tumors and 2 of 2 mature teratomas. On the other hand, immunostaining was negative in all of serous cystadenoma, mucinous cystadenoma, mucinous cystadenocarcinoma, dysgerminoma and immature teratoma. The PTHrP expression appears to be dependent on the histologic type of malignancy and prevalent in clear cell carcinoma, serous cystadenocarcinoma and yolk sac tumor.