文摘
Summary
HER2/neu alteration detection in breast cancer is important for decision making of the HER2-targeted therapy. We retrospectively analyzed the HER2/neu status by fluorescence in situ hybridization and HER2 protein expression by immunohistochemistry in a cohort of 481 patients with invasive breast cancer. Fluorescence in situ hybridization showed that 57.4 % of cases exhibited HER2 amplification but 41.4 % did not, and 1.2 % exhibited an equivocal status. Immunohistochemistry showed that 10.4 % , 16.8 % , 38.3 % , and 34.5 % of cases had scores of 0, 1+, 2+, and 3+, respectively. The HER2 status showed a moderate agreement with HER2 expression with a score of 0, 1+, and 3+ (¦Ê = 0.576, P < .05), and the concordance rate was 90 % , 61.7 % , and 83.1 % , respectively. The HER2 amplification occurred more likely in cases with higher immunohistochemistry scores (P < .001), and polysomy 17 was observed in 28.3 % of cases, but more frequently in the HER2 amplification subgroup (33.3 % ) than in the HER2 nonamplification subgroup (20.1 % ) (P < .05). There was no significant correlation between the frequency of polysomy 17 and immunohistochemistry scores (P > .05). In the immunohistochemistry 2+ group, 56.5 % cases showed HER2/neu amplification, and polysomy 17 occurred more likely in the HER2 amplification subgroup (34.6 % ) than in the HER2 nonamplification group (13.0 % ) (P < .001). We concluded that the HER2 status was correlated with HER2 protein expression levels, and it is necessary to determine the HER2 status for cases with immunohistochemistry 2+. The frequency of polysomy 17 was correlated with the HER2 copy number and partially contributed to HER2/neu amplification but not HER2 protein expression.
