HER-2/neu protein expression in breast cancer evaluated by immunohistochemistry. A study of interlaboratory agreement.
Immunohistochemistry (IHC) is used commonly for evaluating HER-2/neu protein expression in breast cancer. Given the potential clinical importance of HER-2/neu status in patient management, interlaboratory variability in HER-2/neu IHC results in a matter of legitimate concern. We compared the results from 2 laboratories for HER-2/neu determined by IHC on paraffin sections of the same 100 consecutive invasive breast cancers. Both laboratories used the same primary antibody; however, different methods for heat-induced epitope retrieval (microwave or steam) and immunostaining (automated equipment from different manufacturers) and different scoring systems (positive-negative and 0-4+) were used. Slides were read in a blinded fashion and the results from the 2 laboratories were compared. Of the 93 cases evaluable in both laboratories, 24% were scored as HER-2/neu-positive at 1 laboratory, and 23% were scored as positive at the other. Complete concordance in categorization of HER-2/neu status between the 2 laboratories was achieved in 90 of 93 cases. Excellent interlaboratory agreement for HER-2/neu IHC was attained using the same primary antibody to HER-2/neu, even without standardization of assay method or scoring criteria. However, standardization of these parameters remains an important objective to optimize interlaboratory agreement.
Jacobs
T W
TW
Department of Pathology, Beth Israel Deaconess Medical Center, Boston, MA 02215, USA.
Gown
A M
AM
Yaziji
H
H
Barnes
M J
MJ
Schnitt
S J
SJ
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001322:Autoanalysis; D001365:Axilla; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology; D005260:Female; D006358:Hot Temperature; D006801:Humans; D007150:Immunohistochemistry / Q000592:standards; D007753:Laboratories / Q000592:standards; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D015588:Observer Variation; D011786:Quality Control; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D011960:Receptors, Estrogen / Q000032:analysis
D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen