title: The triple negative paradox: primary tumor chemosensitivity of breast cancer subtypes.
abstract: OBJECTIVE
  Gene expression analysis identifies several breast cancer subtypes. We examined the relationship of neoadjuvant chemotherapy response to outcome among these breast cancer subtypes.
  
  
  METHODS
  We used immunohistochemical profiles [human epidermal growth factor receptor 2-positive (HER2+)/hormone receptor-negative for HER2+/estrogen receptor-negative (ER-), hormone receptor and HER2- for basal-like, hormone receptor-positive for luminal] to subtype a prospectively maintained data set of patients with breast cancer treated with neoadjuvant anthracycline-based (doxorubicin plus cyclophosphamide, AC) chemotherapy. We analyzed each subtype for clinical and pathologic response to neoadjuvant chemotherapy and examined the relationship of response to distant disease-free survival and overall survival.
  
  
  RESULTS
  Of the 107 patients tested, 34 (32%) were basal-like, 11 (10%) were HER2+/ER-, and 62 (58%) were luminal. After neoadjuvant AC, 75% received subsequent chemotherapy and all received endocrine therapy if hormone receptor-positive. The chemotherapy regimen and pretreatment stage did not differ by subtype. Clinical response to AC was higher among the HER2+/ER- (70%) and basal-like (85%) than the luminal subtypes (47%; P < 0.0001). Pathologic complete response occurred in 36% of HER2+/ER-, 27% of basal-like, and 7% of luminal subtypes (P = 0.01). Despite initial chemosensitivity, patients with the basal-like and HER2+/ER- subtypes had worse distant disease-free survival (P = 0.04) and overall survival (P = 0.02) than those with the luminal subtypes. Regardless of subtype, only 2 of 17 patients with pathologic complete response relapsed. The worse outcome among basal-like and HER+/ER- subtypes was due to higher relapse among those with residual disease (P = 0.003).
  
  
  CONCLUSIONS
  Basal-like and HER2+/ER- subtypes are more sensitive to anthracycline-based neoadjuvant chemotherapy than luminal breast cancers. Patients that had pathologic complete response to chemotherapy had a good prognosis regardless of subtype. The poorer prognosis of basal-like and HER2+/ER- breast cancers could be explained by a higher likelihood of relapse in those patients in whom pathologic complete response was not achieved.
authors: Division of Hematology/Oncology, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7305, USA. Lisa_Carey@med.unc.edu
authors: Lisa A
authors: LA
authors: Carey
authors: E Claire
authors: EC
authors: Dees
authors: Lynda
authors: L
authors: Sawyer
authors: Lisa
authors: L
authors: Gatti
authors: Dominic T
authors: DT
authors: Moore
authors: Frances
authors: F
authors: Collichio
authors: David W
authors: DW
authors: Ollila
authors: Carolyn I
authors: CI
authors: Sartor
authors: Mark L
authors: ML
authors: Graham
authors: Charles M
authors: CM
authors: Perou
mesh_terms: D000328:Adult; D000368:Aged; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use*; D001943:Breast Neoplasms / Q000188:drug therapy* / Q000401:mortality / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009367:Neoplasm Staging; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis; D011960:Receptors, Estrogen / Q000032:analysis; D011980:Receptors, Progesterone / Q000032:analysis; D016019:Survival Analysis
chemical_list: D000970:Antineoplastic Agents; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone