Epithelial mucin expression in bladder cancer: correlation with pathological and clinical parameters

Recently, attention has been drawn to the role of polymorphic epithelial mucin (PEM) as a possible target for cancer immunotherapy. To investigate the expression of this molecule in bladder tissue, we used two mouse monoclonal antibodies (HMFGI and HMFG2) raised against the core protein of the PEM. The localization of these two anti-PEM antibodies was examined in normal (n = 10), inflammatory (n = 10) and malignant (n = 67) bladder tissue samples with the use of a three-step avidin-biotin method. For HMFG1 and HMFG2 localization was successful in 78% and 60% of the bladder cancer samples, respectively, where as they were localized only in 30% and 40% of normal bladder tissue samples, respectively. Staining of either antibodies did not correlate with the grade, stage, or survival of bladder cancer patients. We conclude that PEM is frequently overexpressed by bladder cancer cells and HMFG1 is the antibody of choice to be used as a carrier of a cytotoxic agent for application of intravesical targeted therapy of bladder cancer.