title: Correlations between molecular subtypes and pathologic response patterns of breast cancers after neoadjuvant chemotherapy.
abstract: BACKGROUND
  The relationship between the pathologic response patterns after neoadjuvant chemotherapy (NAC) and specific subtypes of breast cancer is unclear.
  
  
  METHODS
  This study retrospectively analyzed 351 tumors from 348 women with breast cancer who received anthracycline and taxane-based NAC and subsequent surgery. Various histopathologic factors were assessed in the pretreatment biopsy and surgery specimens based on molecular subtypes defined by immunohistochemistry.
  
  
  RESULTS
  The tumors without a pathologic complete response in each subtype retained their morphologic features after NAC. Lymphocytic infiltration was higher in the hormone receptor-negative (HR-) tumors than in the HR+ tumors. The HR- tumors showed more necrosis and histiocytic infiltration in the tumor bed than the HR+ tumors. The overall (including in situ carcinoma) and invasive pathologic cancer sizes were similar for the triple-negative tumors only. Although all the subtypes showed significantly reduced tumor size after NAC, the difference between the pre-NAC magnetic resonance imaging (MRI) tumor size and the overall pathologic cancer size was significantly smaller for the HR+/human epidermal growth factor receptor 2-negative (HER2-) subgroup than for the triple-negative subgroup. The triple-negative tumors showed the highest correlation between post-NAC tumor size measured by MRI and overall or invasive pathologic tumor size.
  
  
  CONCLUSIONS
  The molecular subtypes of breast cancer have characteristic pathologic patterns of response to NAC.
authors.affiliation: Department of Pathology, University of Ulsan College of Medicine, Asan Medical Center, Seoul, Korea.
authors.forename: Hee Jin
authors.initials: HJ
authors.lastname: Lee
authors.forename: In Hye
authors.initials: IH
authors.lastname: Song
authors.forename: An Na
authors.initials: AN
authors.lastname: Seo
authors.forename: Bora
authors.initials: B
authors.lastname: Lim
authors.forename: Joo Young
authors.initials: JY
authors.lastname: Kim
authors.forename: Jeong-Ju
authors.initials: JJ
authors.lastname: Lee
authors.forename: In Ah
authors.initials: IA
authors.lastname: Park
authors.forename: Jinho
authors.initials: J
authors.lastname: Shin
authors.forename: Jong Han
authors.initials: JH
authors.lastname: Yu
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Ahn
authors.forename: Gyungyub
authors.initials: G
authors.lastname: Gong
mesh_terms: D000328:Adult; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000188:drug therapy* / Q000473:pathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008875:Middle Aged; D020360:Neoadjuvant Therapy; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D016896:Treatment Outcome
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases