The HER2 gene copies per tumor cell either before or after correction for chromosome-17 correlated significantly with HER2 IHC results in epithelial ovarian cancer in a tissue microarray study.
BACKGROUND
HER2 gene amplification and HER2 protein overexpression are important factors in predicting clinical sensitivity to anti-HER2 monoclonal antibody therapy in breast cancer patients. The purpose of this study is to evaluate the correlation between HER2 protein expressions and the HER2 gene copies per tumor cell either before or after chromosome-17 correction in epithelial ovarian cancer (EOC).


METHODS
Adopting 2007 ASCO/CAP guideline recommendations for HER2 testing, 27 tissue microarray (TMA) samples from EOC patients were analyzed by immunohistochemistry (IHC) using Dako, c-erb-B2 antibody and subsequently examined by fluorescence in situ hybridization (FISH) using Abbott/Vysis, PathVysion HER2 DNA Probe Kit.


RESULTS
The overall concordance revealed 81.5% between HER2 IHC and HER2 FISH results. Additionally, HER2 gene copies prior to chromosome-17 correction increased significantly in a stepwise order through the negative, equivocal, and positive IHC result categories (P = 0.026), as did the HER2 gene copies after chromosome-17 correction (P = 0.028). On the other hand, HER2 IHC results correlated significantly with both chromosome-17 uncorrected HER2 gene copy numbers (ρ = 0.430, P = 0.025) and chromosome-17 corrected HER2 gene copy numbers (ρ = 0.524, P = 0.027).


CONCLUSIONS
We demonstrated that both chromosome-17 corrected and uncorrected HER2 gene copies correlated significantly with HER2 IHC result categories; and tests for the HER2 gene copies per tumor cell either before or after correction for chromosome-17 can be applied as a potentially valuable tool in analyzing the HER2 status in EOC.
Department of Obstetrics and Gynecology, Po-Jen General Hospital, Taipei, Taiwan.
Wen-Chih
WC
Tsai
Ming-Yung
MY
Lee
Fong-Lin
FL
Chen
Po-Hui
PH
Wang
Wea-Lung
WL
Lin
Alexandra
A
Ruan
Yi-Ju
YJ
Li
Shao-Chuan
SC
Wang
Hung
H
Chiang
Chih-Ping
CP
Han
D002886:Chromosomes, Human, Pair 17 / Q000235:genetics*; D005260:Female; D005784:Gene Amplification; D018628:Gene Dosage; D018734:Genes, erbB-2; D006801:Humans; D007150:Immunohistochemistry; D017404:In Situ Hybridization, Fluorescence; D046228:Microarray Analysis; D010051:Ovarian Neoplasms / Q000235:genetics* / Q000378:metabolism; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism; D018709:Statistics, Nonparametric
D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human