Expression of p120, Ki-67 and PCNA as proliferation biomarkers in imprint smears of prostate carcinoma and their prognostic value

The cell proliferation markers p120, Ki-67 and proliferating cell nuclear antigen (PCNA) recognize nuclear antigens. The expression of these proteins by immunostaining methods was reported to be of value in determining the prognosis of patients with malignant diseases. In this study, we evaluated the prognostic significance of the expression of nuclear antigens p120, PCNA and Ki-67 in prostate cancer and compared the results with other prognostic factors. Imprint smear samples obtained from 70 patients immediately after radical prostatectomy for prostatic carcinoma were immunostained with monoclonal antibodies against p120, Ki-67 and PCNA. The immunostaining results were correlated with Gleason score, tumour differentiation, stage and prostatic specific antigen (PSA) levels. Our findings demonstrate that p120, Ki-67 and PCNA expression in prostatic carcinoma smears, correlated significantly with the degree of Gleason score (P < 0.001). When combining p120, Ki-67 and PCNA positivity with tumour differentiation there was a significant association among these parameters (P < 0.001). Overexpression of p120, Ki-67 and PCNA, was also associated with increased PSA serum levels (>4 ng/ml) (P < 0.001). The distribution of p120, Ki-67 and PCNA expression in prostate carcinomas was not statistically significant for Ki-67 (P = 0.69) and p120 (P = 0.22) but was significant for PCNA (P < 0.001) as far as the histological stage (T2a, T2b, T2c, T3a). P120, Ki-67 and PCNA expression had significant prognostic value for disease-free survival. Our results conclude that nuclear antigens p120, Ki-67 and PCNA appear to be additional markers in the field of prognosis of prostatic carcinoma.