Human carcinoma-associated antigen (HCA) is a mucin protein whose level is increased in the sera of patients with a variety of carcinomas. We have previously shown that prostatic carcinoma overexpresses HCA in comparison to benign prostatic tissue. To our knowledge, expression of HCA in other tumors has not been reported previously.
The current study was designed to determine if HCA is overexpressed in urothelial carcinoma (UCa) of the bladder.
Forty cystectomy specimens with UCa were selected, of which 27 cases had invasive UCa, 21 cases had a noninvasive component, and 36 cases had benign urothelium. Seven cystectomy specimens with benign conditions were chosen as controls. Anti-HCA monoclonal antibody HAE3 was used for immunohistochemical staining. Results were recorded as positive (> or =5% of cells staining and staining intensity 2+ or 3+) or negative (<5% of cells staining or staining intensity <2+) and analyzed using the Fisher exact test.
HAE3 staining was positive in 67% of invasive UCa, 29% of noninvasive UCa, but only 5% of benign urothelium specimens. The difference in HCA expression between benign urothelium and UCa and that between invasive and noninvasive UCa was statistically significant (P =.008). No statistically significant difference was found between low-grade and high-grade noninvasive papillary UCa (P =.06).
Human carcinoma-associated antigen is selectively overexpressed in a significant number of cases of UCa of the bladder, suggesting the potential utility of monitoring the serum and/or urine levels of HCA in monitoring patients with HCA-positive UCa for recurrence or progression.