抄録
We evaluated HER-2/neu status in both primary tumor and corresponding lymph node metastasis in 56 cases of invasive ductal carcinoma of the breast by immunohistochemistry using three different antibodies (monoclonal antibodies CB11 and TAB250 and DAKO polyclonal antibody) and FISH (31 cases of primary tumor and 20 cases of lymph node metastasis) in serial tissues sections of archival materials. There was a significant positive correlation in immunohistochemical scoring between primary and lymph node metastasis with all three antibodies employed (R2=0.51, p<0.0001 for CB11, R2=0.24, p<0.001 for TAB250, R2 =0.39, p<0.0001 for DAKO). This finding indicated that the assessment of HER-2/neu status in the primary tumor specimens in the archival materials for determining the application of trastuzumab may be justified at the time of carcinoma recurrence. HER-2/neu was interpreted as amplified in 6/31 cases (19%) in primary tumor and 4/20 cases (20%) in lymph node metastasis. In primary tumor, a significant positive correlation was detected between immunohistochemistry and FISH only in CB11 (p<0.0001) but not in TAB 250 (p<0.0625) and DAKO (p=0.1056). In lymph node metastasis, a significant positive correlation was detected in CB11 (p=0.0018) and TAB250 (p=0.0012) but not in DAKO. This relatively inappropriate high immunohistochemical positivity of HER-2/neu and a lack of correlation with results of FISH analysis in breast carcinoma using a DAKO polyclonal antibody indicated that antibodies other than this polyclonal antibody should also be prospectively validated in future standardization of HER-2/ neu immunohistochemical analysis.
