Js. Ross et al., PROGNOSTIC-SIGNIFICANCE OF HER-2 NEU GENE AMPLIFICATION STATUS BY FLUORESCENCE IN-SITU HYBRIDIZATION OF PROSTATE CARCINOMA/, Cancer, 79(11), 1997, pp. 2162-2170
BACKGROUND. HER-2/neu gene amplification, established as a prognostic
factor in breast carcinoma and other cancers, has not been correlated
with outcome in prostate carcinomas (PCs). METHODS. HER-2/neu gene amp
lification was determined by automated fluorescence in situ hybridizat
ion (FISH) using a unique sequence cosmid probe on 113 formalin fixed,
paraffin embedded 4-mu m tissue sections and the results compared wit
h tumor grade, DNA ploidy, HER-2/neu protein expression by immunohisto
chemistry (IHC), serum prostate specific antigen, pathologic stage, an
d postoperative disease recurrence (mean follow-up of 44 months). RESU
LTS. HER-2/neu gene amplification by FISH (41% of PCs) correlated with
tumor grade (P = 0.001) and DNA ploidy status (P = 0.0003). HER-2/neu
protein overexpression by IHC (29% of PCs) correlated with grade (P =
0.03), but not with DNA ploidy. A trend for similar HER-2/neu status
in each PC by MC and FISH did not reach statistical significance (P =
0.25). On univariate analysis, HER-2/neu amplification by FISH (P = 0.
029), tumor grade (P = 0.013), and DNA ploidy (P = 0.016) correlated w
ith postoperative disease recurrence. HER-2/neu expression by IHC did
not correlate with outcome. On multivariate analysis, grade (P = 0.000
1) and ploidy (P = 0.001) were independent outcome predictors; HER-2/n
eu amplification by FISH reached near-independent significance (P = 0.
125). CONCLUSIONS. HER-2/neu gene amplification by FISH on archival PC
s significantly correlates with grade and DNA ploidy status, is more s
ensitive than IHC in detecting HER-2/neu gene abnormalities, predicts
postoperative disease recurrence, and may prove important in planning
therapy for patients with prostate carcinoma. (C) 1997 American Cancer
Society.