HER-2/neu Expression in Prostate Adenocarcinoma: A Systematic Review and Meta-Analysis

Purpose: HER-2/neu has been linked to the clinical progression of hormone independent prostate cancer. We performed a meta-analysis to investigate the prognostic impact of HER-2/neu over expression in patients with prostate adenocarcinoma, and its correlation with other pathological and clinical variables. Materials and Methods: We searched the MEDLINE (R), Embase (R), CancerLit (R) and ASCO (R) abstract databases for published studies of HER-2/neu protein expression in primary prostate cancer tissue with a median followup of greater than 2 years and data on survival in patients with and without HER-2/neu over expression. We separately analyzed studies reporting HER-2/neu soluble receptor levels in patients with prostate cancer. Results: We included 38 articles with a total of 5,976 patients. The overall RR of death in those with HER-2/neu over expression in the primary tumor was 1.63 (95% CI 1.47-1.82, p <0.0001). In the presence of over expression the recurrence RR was 1.87 (95% CI 1.59-2.21, p <0.0001). High HER-2/neu extracellular domain levels also correlated with death (RR 2.01, 95% CI 1.21-3.35, p = 0.007) and recurrence (RR 1.74, 95% CI 1.41-2.15, p <0.0001). Conclusions: There is a consistent association of HER-2/neu over expression and Gleason less than 7 with a higher RR of death and recurrence in patients with prostate cancer. Further clinical trials should test the hypothesis that HER-2/neu is a marker of a clinically worse outcome in patients with prostate cancer and a potential target for therapy.