Influence of neoadjuvant chemotherapy on HER2/neu status in invasive breast cancer.

Peifeng Li, Tantan Liu, Yingmei Wang, Shuai Shao, Weichen Zhang, Yang Lv, Jun Yi, Zhe Wang

State Key Laboratory of Cancer Biology, Department of Pathology, Xijing Hospital and School of Basic Medicine, Fourth Military Medical University, Xi'an, P.R. China.

Clinical breast cancer 2013 Feb

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Reliably estimating HER2/neu expression in breast cancer is important for predicting patient prognosis and optimizing adjuvant therapeutic strategies. In this retrospective cohort study, effects of NAC on HER2/neu status in invasive breast cancer were evaluated, and the related factors were analyzed. One hundred thirty-one patients with primary breast cancer were treated with anthracycline- and/or taxane-based NAC. HER2/neu status was evaluated by IHC on core needle biopsies of primary tumors before NAC and surgical resection specimens of post-NAC residual breast cancers or tumor-positive axillary lymph nodes. Thirty-two pairs of specimens with discordant HER2/neu IHC scores were analyzed by fluorescence in situ hybridization (FISH). A significant difference in HER2/neu status by IHC between core needle biopsies and surgical resection specimens in patients receiving NAC was observed. After NAC, 23.4% (29 of 124) of tumors showed downregulated HER2/neu expression by IHC. Alterations of HER2/neu IHC scores did not significantly correlate with tumor subtype, pathologic response to NAC, adjuvant regimen, or time interval from the last chemotherapy to surgery. HER2/neu protein overexpression level was associated with favorable pathologic response to anthracycline and taxane-based chemotherapy. However, tumors with altered HER2/neu IHC scores after NAC revealed stable HER2/neu gene amplification/nonamplification by FISH analysis. Neoadjuvant chemotherapy for breast carcinoma resulted in the HER2/neu status alteration by IHC, but they have stable gene amplification status by FISH. HER2/neu protein overexpression indicated greater sensitivity to neoadjuvant anthracycline- and taxane-based chemotherapy. Thus, retesting HER2/neu IHC status in residual tumors after NAC should be considered in order to optimize adjuvant systemic therapy. Copyright © 2013 Elsevier Inc. All rights reserved.

Citation

Peifeng Li, Tantan Liu, Yingmei Wang, Shuai Shao, Weichen Zhang, Yang Lv, Jun Yi, Zhe Wang. Influence of neoadjuvant chemotherapy on HER2/neu status in invasive breast cancer. Clinical breast cancer. 2013 Feb;13(1):53-60