title: Presenting features of breast cancer differ by molecular subtype.
abstract: BACKGROUND
  Gene expression profiling of breast cancers identifies distinct molecular subtypes that affect prognosis. Our goal was to determine whether presenting features of tumors differ among molecular subtypes.
  
  
  METHODS
  Subtypes were classified by immunohistochemical surrogates as luminal A (estrogen receptor [ER] and/or progesterone receptor [PR] positive, HER-2-), luminal B (ER and/or PR+, HER-2+), HER-2 (ER and PR-, HER-2+), or basal (ER, PR, HER-2-). Data were obtained from an established, registered database of patients with invasive breast cancer treated at our institution between January 1998 and June 2007. A total of 6,072 tumors were classifiable into molecular subtypes. The chi(2) test, analysis of variance, and multivariate logistic regression analysis were used to determine associations between subtype and clinicopathologic variables.
  
  
  RESULTS
  The distribution of subtypes was luminal A, 71%; luminal B, 8%; HER-2, 6%; and basal, 15%. Marked differences in age, tumor size, extent of lymph node involvement, nuclear grade, multicentric/multifocal disease, lymphovascular invasion (LVI), and extensive intraductal component were observed among subtypes. When compared with luminal A tumors, those overexpressing HER-2 (luminal B, HER-2) were significantly more likely to manifest nodal involvement, multifocal, extensive intraductal component, and LVI (P < 0.0001). On multivariate analysis, after controlling for patient age, tumor size, LVI, and nuclear grade, HER-2 subtype tumors were 2.0 times more likely to have four or more metastatic lymph nodes (P < 0.0001) and 1.6 times more likely to have multifocal disease (P < 0.0001) compared with patients with luminal A.
  
  
  CONCLUSIONS
  Tumor presentation varies among molecular subtypes; this information may be useful in selecting local therapy. Neoadjuvant therapy and lymph nodes evaluation before surgery or neoadjuvant therapy are likely to be beneficial in HER-2-overexpressing tumors.
authors: Breast Service, Department of Surgery, Memorial Sloan-Kettering Cancer Center, New York, NY, USA.
authors: Lisa
authors: L
authors: Wiechmann
authors: Michelle
authors: M
authors: Sampson
authors: Michelle
authors: M
authors: Stempel
authors: Lindsay M
authors: LM
authors: Jacks
authors: Sujata M
authors: SM
authors: Patil
authors: Tari
authors: T
authors: King
authors: Monica
authors: M
authors: Morrow
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D005260:Female; D006801:Humans; D008198:Lymph Nodes / Q000473:pathology; D008207:Lymphatic Metastasis; D008875:Middle Aged; D009361:Neoplasm Invasiveness; D009367:Neoplasm Staging; D018295:Neoplasms, Basal Cell / Q000175:diagnosis* / Q000378:metabolism; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism*; D011960:Receptors, Estrogen / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism*; D055815:Young Adult
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone