Evaluation of HER‐2/neu expression in prostatic adenocarcinoma

Abstract

BACKGROUNDSome evidence suggests a role for HER‐2/neu overexpression in prostate carcinoma progression. Reported rates of HER‐2/neu overexpression in patients with prostate carcinoma vary greatly.METHODSThe authors studied radical prostatectomy specimens from 38 patients who had biochemical failure after undergoing radical prostatectomy for prostate carcinoma. Immunohistochemistry for HER‐2/neu overexpression using the HercepTest kit (Dako Corporation, Carpenteria, CA) was employed. Two different antigen‐retrieval techniques were used: 1) the standard U.S. Food and Drug Administration (FDA)‐approved HercepTest assay and 2) a modified HercepTest, which employed an alkaline citrate buffer, pH 9.0, for antigen retrieval and a 1‐hour primary antibody incubation time. The level of HER‐2/neu expression was evaluated on a scale from 0 (no staining) to 3+ according to the published guidelines. Fluorescent in situ hybridization for gene amplification was performed on all specimens.RESULTSWith the standard technique, only one specimen had 2+ staining, and no specimens had 3+ staining. With the modified technique, 10 specimens (26%) had 2+ staining, and 9 specimens (24%) had 3+ staining. There was a significant association between the level of HER‐2/neu expression shown with the modified technique and tumor stage (P = 0.03) as well as Gleason grade (P = 0.01). None of the specimens had HER‐2/neu gene amplification.CONCLUSIONSThe authors report a simple modification of the HercepTest that resulted in an increased rate of HER‐2/neu expression, which was correlated with poor‐risk pathologic findings. The findings suggest that adenocarcinoma of the prostate should be evaluated for HER‐2/neu expression with a prostate specific immunohistochemical procedure that differs from the FDA‐approved standard procedure. Cancer 2002;95:1650–5. © 2002 American Cancer Society.DOI 10.1002/cncr.10839

Carcinosarcoma of the prostate: two cases with distinctive morphologic and immunohistochemical findings

“…We observed intense and selective overexpression of c-erb B2 in these areas, this being the first report of such pattern in CS. This is an immunohistochemical feature seldom reported in conventional prostatic adenocarcinoma [27], but interestingly present in our two patients.…”

ErbB-2 signaling plays a critical role in regulating androgen-sensitive and castration-resistant androgen receptor-positive prostate cancer cells

“…Nevertheless, despite recent advances in PCa research and in part due to the lack of suitable cell models, the role of ErbB-2 vs. EGFR in androgen-stimulated proliferation is still not fully understood. Furthermore, the investigation on the role of EGFR and ErbB-2 activation and/or overexpression in the development of CR PCa cells is inconsistent [14–20]. Therefore, in the present study, we used two independent in vitro cell models which respectively include AS and CR cells and recapitulates clinical PCa progression from AS to CR stage to determine the role of EGFR vs. ErbB-2 activation in androgen-stimulated proliferation and CR PCa cell growth.…”

“…Concurrently, other studies showed higher levels of ErbB-2 protein in some prostatic tumors than normal controls [17–19]. Analyses of clinical specimens showed that ErbB-2 protein may be elevated in a subset of CR PCa [20–23]. Conversely, inhibition of ErbB-2 results in the suppression of xenograft tumor growth and decreases AR transcriptional activity [24, 25].…”

Immunotherapy and Immune Evasion in Prostate Cancer

“…In prostate cancer, Her2/ neu (HER2) over expression is reported to high [54,55,56]. Patients with HER2 positive (2+ or higher on IHC) cancers have better survival and lower relapse rates as compared to the HER2 negative prostate cancers [57].…”