Immunohistochemical and ultrastructural localization of tissue polypeptide antigen in human ovarian tumours

Forty specimens of benign and malignant ovarian tumours were studied for localization of tissue polypeptide antigen (TPA) at light and electron microscopic levels by an indirect immunoperoxidase technique. Of the 30 ovarian carcinomas, 23 (77%) were positive and 7 (23%) were negative for TPA, while of the 10 benign ovarian tumours 3 (30%) were positive and 7 (70%) were negative. Positive reaction did not correlate with the tumour grade. Of the 10 patients with metastasis, 8 (80%) had positive tumours. Staining for TPA was observed at the intraluminal cell surfaces and peripheral cell membranes. The ultrastructural localization of TPA revealed electron-dense reaction products at the cell surface and microvillous surfaces. These results provide confirmatory and supplementary evidence to support the previous findings of TPA in the serum and suggest that testing for TPA in ovarian tumors has a limited prognostic importance and a poor diagnostic value. The surface property of TPA suggests that the cell membrane is involved in secretion and probably synthesis of TPA.