Context: Prostate cancer is the most frequent solid genitourinary neoplasm in men. Involvement of several genes has been described in the promotion and progression of prostate carcinoma.
Objective: To study the expression of the oncogenes HER2/neu and BCL2, tumor suppressor gene p53 and the tumor proliferation rate in 150 radical prostatectomy specimens, in order to define their role as prognostic parameters in localized prostate cancer.
Type of study: Prospective study.
Setting: Universidade Federal de São Paulo and Hospital Sírio Libanês, Sao Paulo
Participants: One hundred and fifty men who were submitted to radical prostatectomy between August 1997 and August 1998, for localized prostate cancer.
Main measurements: All specimens underwent evaluation in their entirety, to determine tumor volume percentage, tumor extent and Gleason score. Immunohistochemistry was performed to determine gene expression using anti- HER2/neu, BCL2 and p53 antibodies, and proliferating cell nuclear antigen. The chi-squared test was used for correlation between gene expression, proliferative activity and histological variables.
Results: Thirty percent of the cases were p53 positive. There was positive correlation between p53 expression and tumor stage. The p53 expression was 22.9% and 42.6% for pT2 and pT3 tumors, respectively (p = 0.01). Expression of HER2/neu, BCL2 and proliferating cell nuclear antigen was identified in 66%, 23% and 43% of patients, respectively. There was no correlation between these three parameters and tumor volume, Gleason score or tumor stage.
Conclusion: One-third of prostate adenocarcinomas express p53 protein, and this characteristic is related to tumor stage. HER2/neu is frequently expressed in prostate carcinomas, with no correlation with histological parameters. BCL2 is rarely expressed, and together with proliferative activity has no relationship with prognostic pathological variables in these neoplasms.