Comparison of fluorescence in situ hybridization (FISH) and dual-ISH (DISH) in the determination of HER2 status in breast cancer.
The determination of HER2 amplification is critical to selecting appropriate patients for HER2 targeted therapy in breast cancer. Dual in situ hybridization (DISH), an alternative to fluorescence in situ hybridization (FISH) and immunohistochemistry, is now available. To compare the FISH and DISH methods, we tested 251 samples enriched for common or difficult-to-assess HER2 anomalies. Seven samples failed DISH testing. There was a 64% (156/244) concordance between FISH and DISH by anomaly (κ = 0.58, 95% confidence interval, 0.51-0.65; P < .0001) and an 83% (203/244) concordance by amplification status (κ = 0.58; 95% confidence interval, 0.47-0.69; P < .0001). DISH resulted in lower estimates of HER2/ centromere 17 ratios than FISH, and many cases that were equivocal with FISH were normal with DISH. DISH did not detect any case with coamplification of HER2 and centromere 17. Using a cohort of difficult specimens, we observed less than 95% concordance between FISH and DISH. DISH may underestimate the HER2/chromosome 17 ratio, or FISH may overestimate this ratio.
Department of Oncology, Mayo Clinic, Rochester, MN 55905, USA.
Aaron S
AS
Mansfield
William R
WR
Sukov
Jeanette E
JE
Eckel-Passow
Yuta
Y
Sakai
Frank J
FJ
Walsh
Melissa
M
Lonzo
Anne E
AE
Wiktor
Ahmet
A
Dogan
Robert B
RB
Jenkins
D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000378:metabolism*; D002503:Centromere / Q000235:genetics; D002886:Chromosomes, Human, Pair 17 / Q000235:genetics; D005260:Female; D005784:Gene Amplification; D006801:Humans; D017403:In Situ Hybridization / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence / Q000379:methods*; D011237:Predictive Value of Tests; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results
D018719:Erb-b2 Receptor Tyrosine Kinases; C508053:ERBB2 protein, human