Comparison of HER2/neu status assessed by quantitative polymerase chain reaction and immunohistochemistry.
We prospectively evaluated a series of 254 breast cancers by quantitative polymerase chain reaction (PCR) and immunohistochemistry using 3 antibodies: HercepTest, CB11, and TAB250. DNA was extracted from a 10-micron tumor section for PCR, and 4-micron serial sections were taken from the same block for immunohistochemistry. The immunohistochemical results were scored using a semiquantitative immunohistochemical system. A positive tumor by immunohistochemistry had a score of 5 or more. The manufacturer's recommended scoring system was used for the HercepTest. Tumors were positive for gene amplification if the ratio of the HER2/neu gene to control gene after normalization was 2 or more. Of 254 cases, 61 showed gene amplification. For immunohistochemistry, 23% of tumors were positive with CB11, 27% with TAB250, and 37% with the HercepTest. Results for each antibody were compared with PCR results. The overall concordance for the HercepTest was 82%, which was significantly lower than that for CB11 (88%) or TAB250 (87%). The specificity for the HercepTest was 80% compared with 90% for TAB250 and 93% for CB11, while the positive predictive value for the HercepTest was 57% compared with 71% and 76% for TAB250 and CB11, respectively.
O'Malley
F P
FP
Mount Sinai Hospital, Dept of Pathology and Laboratory Medicine, 600 University Ave, Toronto, ON, M5G1X5 Canada.
Parkes
R
R
Latta
E
E
Tjan
S
S
Zadro
T
T
Mueller
R
R
Arneson
N
N
Blackstein
M
M
Andrulis
I
I
D000911:Antibodies, Monoclonal / Q000627:therapeutic use; D061067:Antibodies, Monoclonal, Humanized; D001706:Biopsy; D001943:Breast Neoplasms / Q000737:chemistry* / Q000628:therapy; D002170:Canada; D005260:Female; D006801:Humans; D007116:Immunization, Passive; D007150:Immunohistochemistry; D009361:Neoplasm Invasiveness / Q000175:diagnosis; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis*; D012680:Sensitivity and Specificity; D000068878:Trastuzumab
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; D000068878:Trastuzumab