Immunohistochemical and ultrastructural investigation of new membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) in gynecologic neoplasms.

New membrane-associated placental tissue proteins (MP2 A, B, C, D, and E) were investigated immunohistochemically by avidin-biotin immunoperoxidase technique and immunoelectron microscopy in various gynecologic neoplasms and normal gynecologic tissues. MP2 A and MP2 B were not specific for malignant tumors. MP2 C was present in 67-100% of ovarian carcinomas, 100% of benign dermoid cysts, and 77% of endometrial carcinomas. Except for endocervical adenocarcinomas, MP2 D was hardly detectable in gynecologic malignancies. Although MP2 E was hardly detectable in benign gynecologic tumors, this protein was present in ovarian carcinomas, uterine squamous carcinomas, endocervical adenocarcinomas, and endometrial adenocarcinomas. These results suggest a possible clinical application of these MP2 proteins as a new tumor marker for gynecologic malignancies.