title: Influence of neoadjuvant chemotherapy on HER2/neu status in invasive breast cancer.
abstract: BACKGROUND
  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.
  
  
  METHODS
  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).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: 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.
authors.forename: Peifeng
authors.initials: P
authors.lastname: Li
authors.forename: Tantan
authors.initials: T
authors.lastname: Liu
authors.forename: Yingmei
authors.initials: Y
authors.lastname: Wang
authors.forename: Shuai
authors.initials: S
authors.lastname: Shao
authors.forename: Weichen
authors.initials: W
authors.lastname: Zhang
authors.forename: Yang
authors.initials: Y
authors.lastname: Lv
authors.forename: Jun
authors.initials: J
authors.lastname: Yi
authors.forename: Zhe
authors.initials: Z
authors.lastname: Wang
mesh_terms: D002288:Adenocarcinoma, Mucinous / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D002280:Basal Cell Carcinoma / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D018275:Carcinoma, Lobular / Q000188:drug therapy / Q000378:metabolism / Q000473:pathology; D016022:Case-Control Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007124:Immunoenzyme Techniques; D017404:In Situ Hybridization, Fluorescence; D008207:Lymphatic Metastasis; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics* / Q000378:metabolism*; D012189:Retrospective Studies
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases