Human carcinoma-associated antigen (HCA) is a mucin glycoprotein recognized by antibodies raised against epiglycanin, the latter having been originally purified from mouse mammary carcinoma cells. Human carcinoma-associated antigen expression is increased in sera of patients with various carcinomas, including prostatic carcinoma. However, to our knowledge, expression of HCA in benign and neoplastic prostatic tissue has not been studied.
To compare the expression of HCA in cells of primary and metastatic prostatic carcinomas with its expression in non-carcinoma-associated cells.
We studied 40 cases of primary and 36 cases of metastatic prostatic carcinomas by immunohistochemical staining with anti-HCA monoclonal antibodies G1 and HAE3. The blocks from primary carcinomas also contained normal prostatic tissue (40 cases), benign prostatic hyperplasia (16 cases), and high-grade prostatic intraepithelial neoplasia (32 cases).
The 2 antibodies stained carcinomas more frequently than normal prostatic tissue, hyperplasia, and prostatic intraepithelial neoplasia (P < .001). The differences in the staining of low-grade versus high-grade tumors was not statistically significant with either antibody. The staining was present in the cytoplasm and on the luminal membrane surface of the tumor cells and in the luminal secretions. In metastatic prostatic carcinomas, G1 and HAE3 staining was positive in 44% and 67% of the cases, respectively.
Our results showed that mucin protein HCA is overexpressed in cells of prostatic carcinoma, which may have value in diagnosis and therapy. Its role in carcinogenesis also merits further study.