[Expression of squamous cell carcinoma-associated antigen in bladder cancer cells--a comparative study with the expression of proliferating cell nuclear antigen (PCNA)].

We investigated the expression of squamous cell carcinoma-associated antigen (SCC-Ag) and proliferating cell nuclear antigen (PCNA) in bladder carcinoma cells using immunohistochemical techniques. Tissues with 10% or more cells stained for SCC-Ag were defined as positive for the antigen. All grade 1-transitional cell carcinomas (TCCs) and 87% of grade 2-TCCs were negative for cytoplasmic SCC-Ag. However, 57.6% of grade 3-TCCs not associated with squamous metaplasia and 80% of those associated with squamous metaplasia showed strongly positive cytoplasmic SCC-Ag. Of squamous cell carcinomas, the well or moderately differentiated carcinomas showed a higher incidence (80-100%) of the antigen in the cytoplasm than the poorly differentiated ones (25%). Nuclear SCC-Ag was found in 63.6% of grade 1-TCCs, 46.3% of grade 2-TCCs and 54.9% of grade 3-TCCs not associated with squamous metaplasia. However, grade 3-TCCs with squamous metaplasia and squamous cell carcinomas were negative for nuclear SCC-Ag. The positive rate for PCNA increased from grade 1 to grade 2, grade 3 without squamous metaplasia and grade 3 with squamous metaplasia in the TCCs. All squamous cell carcinomas showed a high positive rate, irrespective of the differentiation. Multiple regression analysis revealed a closer association between the expression of cytoplasmic SCC-Ag and the histological grade of TCCs.