HER-2 expression and gene amplification in high-grade PIN and prostate cancer.

The aim of the current study was to analyze HER-2 expression and gene amplification in prostate cancer and HGPIN incidentally detected in cystoprostatectomies. Eighty prostate cases were used. Group 1 (incidental): nineteen cystoprostatectomy specimens with prostate cancer and HGPIN and no residual urothelial carcinoma in the prostate. Group 2 (untreated): twenty-five radical prostatectomy specimens with prostate cancer Group 3 (hormonally treated): nineteen radical prostatectomy specimens with prostate cancer. All the patients were under total androgen ablation therapy for three months before surgery. Group 4 (hormone-independent): nine TURP specimens with locally recurrent androgen independent prostate cancer Group 5 (normal reference): eight cystoprostatectomy specimens without HGPIN and without prostate cancer, and no residual urothelial carcinoma. None of the patients belonging to Groups 1, 2, and 5 had received chemotherapy, hormone therapy, or radiation therapy before surgery. Weak to moderate HER-2 membrane immunoreactivity was observed in most of the basal cells but not in the secretory cells of normal prostatic ducts and acini both in the cystoprostatectomies and in the radicals of the untreated patients. High-grade PIN. HER-2 overexpression was present in the secretory cells in 26% of HGPIN cases in the CyP group, 40% in the untreated clinically detected cancer group, and 83% in the treated group. Prostate cancer HER-2 overexpression was seen in 16% of cases in the CyP group, 36% in the untreated group and 47.5% in the treated group. HER-2 overexpression was present in 78% of cases with androgen independent PCa. Association of HER-2 overexpression and gene amplification. When considering HGPIN the lowest proportion of cases with HER-2 overexpression and with nuclei with gene amplification was seen in the CyP specimens (7%), whereas the highest was in the treated material (28%). As far as the cancers were concerned, the proportions were slightly higher than in HGPIN, the lowest value being in the CyP specimens (9%) and the highest in the hormone independent PCa (62.5%). A statistically significant difference in the number of cases with both overexpression and amplification was only seen between CyP and hormone-independent cancers (p = 0.007).