Concordance in judgments among c-erbB-2 (HER2/neu) overexpression detected by two immunohistochemical tests and gene amplification detected by Southern blot hybridization in breast carcinoma.
We compared the c-erbB-2 protein overexpression status detected by the HercepTestTM (DAKO A/S, Grostrup, Denmark) with another conventional immunohistochemistry system using an anti-c-erbB-2 rabbit polyclonal antibody (Nichirei Co., Tokyo, Japan) and with the c-erbB-2 gene amplification status detected by Southern blot hybridization in 101 surgically resected breast carcinomas. According to the criteria for overexpression, recommended by the manufacturer, c-erbB-2 overexpression by HercepTestTM was detected in 24 cancers (24%), comprising six score-2 tumors and 18 score-3 tumors. The level of agreement in judgment of the HercepTestTM, among three independent observers, was excellent (kappa = 0.845). C-erbB-2 overexpression by Nichirei's antibody and c-erbB-2 gene amplification were detected in 21% and 16% of cases, respectively, and their concordance with HercepTestTM scores of 2-3 was 89% and 90%, respectively. In the score-3 cases by Hercep TestTM only, the concordance rates with overexpression by Nichirei's immunohistochemistry and with gene amplification were slightly higher, 94% and 93%, respectively. Score-2 cases by HercepTestTM were mostly judged as negative overexpression by Nichirei's antibody and as no amplification by Southern blot hybridization. The present results showed that HercepTestTM score-3 detected c-erbB-2 overexpression almost optimally as well as the conventional methods and the score-3 breast carcinomas had clinical and biological implications. Further examination would be necessary to decide the significance of breast cancers of HercepTestTM score 2.
Tsuda
H
H
Pathology Division, National Cancer Center Research Institute and Hospital, Tokyo, Japan. htsuda@cc.ndmc.ac.jp
Tani
Y
Y
Hasegawa
T
T
Fukutomi
T
T
D015139:Blotting, Southern; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000601:surgery; D002277:Carcinoma / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000556:secondary / Q000601:surgery; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D006801:Humans; D007150:Immunohistochemistry / Q000379:methods*; D008875:Middle Aged; D009367:Neoplasm Staging; D015588:Observer Variation; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D015203:Reproducibility of Results; D015996:Survival Rate
D004273:DNA, Neoplasm; D011933:Reagent Kits, Diagnostic; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone