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.
Department of Laboratory Medicine and Pathology, University of Minnesota Medical School, Minneapolis, MN 55455, USA.
Michelle
M
Dolan
Dale
D
Snover
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