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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
Author(s) -
Tsuda Hitoshi,
Tani Yoichi,
Hasegawa Tadashi,
Fukutomi Takashi
Publication year - 2001
Publication title -
pathology international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.73
H-Index - 74
eISSN - 1440-1827
pISSN - 1320-5463
DOI - 10.1046/j.1440-1827.2001.01163.x
Subject(s) - concordance , immunohistochemistry , breast carcinoma , pathology , carcinoma , southern blot , breast cancer , gene duplication , biology , medicine , microbiology and biotechnology , gene , cancer , genetics
We compared the c‐erbB‐2 protein overexpression status detected by the HercepTest TM (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‐ erb B‐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 HercepTest TM was detected in 24 cancers (24%), comprising six score‐2 tumors and 18 score‐3 tumors. The level of agreement in judgment of the HercepTest TM , among three independent observers, was excellent ( κ = 0.845). C‐erbB‐2 overexpression by Nichirei's antibody and c‐ erb B‐2 gene amplification were detected in 21% and 16% of cases, respectively, and their concordance with HercepTest TM scores of 2–3 was 89% and 90%, respectively. In the score‐3 cases by Hercep Test TM 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 HercepTest TM were mostly judged as negative overexpression by Nichirei's antibody and as no amplification by Southern blot hybridization. The present results showed that HercepTest TM 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 HercepTest TM score 2.