Comparison of immunohistochemical and fluorescence in situ hybridization assessment of HER-2 status in routine practice.
Because HER-2 expression in invasive carcinoma of the breast has well-documented ramifications for treatment and prognosis, accurate assessment of HER-2 status is critical. Comparative studies have shown high concordance rates between immunohistochemical analysis and fluorescence in situ hybridization (FISH) in cases with immunohistochemical scores of 0 or 1+ (negative) and 3+ (strongly positive) and low concordance rates among cases with immunohistochemical scores of 2+. The present study was performed to determine concordance rates in a setting more representative of routine clinical practice, in which multiple pathologists submit specimens to a single cytogenetics referral laboratory. We found a higher rate of discordance between immunohistochemical analysis and FISH (approximately 92%) in the groups with immunohistochemical scores of 2+ than reported in other studies. These results strongly support the practice of performing FISH in all cases with immunohistochemical scores of 2+, particularly in routine practice, in which interobserver variability in immunohistochemical scoring among multiple pathologists is likely to be high.
Dolan
Michelle
M
Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
Snover
Dale
D
D014408:Biomarkers, Tumor / Q000032:analysis; D001943:Breast Neoplasms / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D018275:Carcinoma, Lobular / Q000737:chemistry / Q000235:genetics* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D017404:In Situ Hybridization, Fluorescence; D015588:Observer Variation; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000235:genetics*; D015203:Reproducibility of Results
D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases