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Evaluation of HER‐2/ neu expression in prostatic adenocarcinoma
Author(s) -
Sanchez Katya M.,
Sweeney Christopher J.,
Mass Robert,
Koch Michael O.,
Eckert George J.,
Geary William A.,
Baldridge Lee Ann,
Zhang Shaobo,
Eble John N.,
Cheng Liang
Publication year - 2002
Publication title -
cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.052
H-Index - 304
eISSN - 1097-0142
pISSN - 0008-543X
DOI - 10.1002/cncr.10839
Subject(s) - medicine , staining , prostate , immunohistochemistry , carcinoma , prostate carcinoma , adenocarcinoma , pathology , prostatectomy , antigen retrieval , prostate specific antigen , prostate cancer , urology , cancer
BACKGROUND Some 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. METHODS The 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. RESULTS With 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. CONCLUSIONS The 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