[In vivo and ex vivo expression of nucleolar proliferation-associated antigens (p120, B23) in the prostate].

Expression of two nucleolar antigens, p120 and B23, was studied in a prostatic carcinoma cell line (LNCaP) and in frozen and paraffin embedded tissue sections of 40 benign and malignant prostatic lesions. The percentage of p120 negative G0/G1 phase cells rose significantly during transition from exponential to plateau growth phase in vitro (from 9% to 32%). In contrast, B23 was equally expressed throughout different cell cycle and growth phases. Thus, nucleoli of almost all stromal and epithelial cells were stained by B23 in tissue sections. P120, however, selectively stained nucleoli of proliferating prostatic epithelium. Whereas 88% (13/15) of benign hyperplasia were p120 negative this was the case in only 24% (6/25) of carcinomas. Using microwave procedure both MoAbs reacted in paraffin sections, but the percentage of p120 negative cases doubled. A routine application to formalin fixed and paraffin embedded tissue cannot be recommended thus far.