Novel Family of Gynecologic Cancer Antigens Detected by Anti-HIV Antibody

Objective: The reactivity of gynecologic cancer proteins with monoclonal antibody (MAb) directed against the human immunodeficiency virus I (HIV-I) was tested. Methods: Cytoplasmic and nuclear proteins, extracted from a broad range of gynecologic cancers obtained during standard surgical procedures, were tested in Western blotting with MAb 5023 developed against the amino acid sequences 308–322 of the envelope protein gp120 of HIV-I. Results: Three cell membrane proteins, M(r)l20,000 (p120), M(r)41,000 (p41), and M(r)24,000 (p24), and one chromatin protein, M(r)24,000 (p24), were detected by MAb 5023 in invasive, poorly differentiated cervical squamous-cell carcinoma; ovarian serous cystadenocarcinoma; poorly and well-differentiated endometrial carcinoma; vulvar squamous-cell carcinoma; and malignant mixed müllerian tumor. The same antigens were identified in cervical carcinoma cell line SiHa. Neither p120 nor p24 was recognized by other MAbs directed against the variable loop of gp120. Antigens p120 and p41 were undetectable in normal ovarian tissue and in biopsy samples of normal vaginal and rectal mucosa. Rectosigmoid cancer as well as colon carcinoma, lung carcinoma, and melanoma cell lines all tested negative. Conclusions: The identified antigens may represent either the products of human genes (proto-onc-ogenes) or, more likely, the products of an unknown virus specifically expressed in female cancer.