title: Utility of a simplified molecular classification of tumors for predicting survival of patients with invasive ductal breast carcinoma.
abstract: BACKGROUND
  In a recent report it was shown that molecular subgroups of early (pT1) breast tumors belonging exclusively to the most common histological variant, ductal-infiltrating carcinoma, showed significantly different clinical and biological features.
  
  
  OBJECTIVE
  To test in a series of patients with ductal-infiltrating carcinoma encompassing all stages of the disease if the above-mentioned biological differences already detected at the earliest stage are ultimately reflected in survival differences.
  
  
  METHODS
  All patients with ductal infiltrating carcinoma operated upon at Hospital de Móstoles, Madrid, Spain, between 1997 and 2002 were included into the study, to allow for at least five years of follow-up for survivors. Of 242 studied patients, according to the International Federation of Gynecology and Obstetrics (FIGO) classification, 37.6% were in stage I, 47.2% in stage II, 11.0% in stage III, and 4.2% in stage IV. According to the simplified molecular classification of Carey et al., 116 tumors (47.9%) expressed estrogen receptors, and did not express c-erb-B2 (Luminal A), 67 (27.7%) coexpressed hormone receptors (either estrogen receptors, progesterone receptors or both) and c-erb-B2 (Luminal B), 33 (13.3%) expressed c-erb-B2 in the absence of hormone receptors (HER-2), and 26 (10.7%) neither expressed hormone receptors, nor c-erb-B2 (triple-negative, basal).
  
  
  RESULTS
  In a univariate model, both disease-free survival and overall survival of the patients were significantly associated with stage (p=0.0003; p<0.0001), histological grade (p<0.0001; p<0.0001), lymphatic vascular space invasion (p=0005; p=0.0044), menopausal status (p=0.04; p=0.034) and molecular subgrouping (p=0.037: p=0.01). In a multivariate model, only stage (p=0.013), grade (p<0.0001), and menopausal status (p=0.007) retained their prognostic power for predicting disease-free survival, and just stage (p<0.0001) and grade (p<0.0001) for predicting overall survival. The molecular classification of the tumors almost reached statistical significance for predicting overall survival (p=0.06).
authors.affiliation: Universidad Rey Juan Carlos, Facultad de Ciencias de la Salud, Avenida de Atenas, SN, 28922 Alcorcón, Madrid, Spain.
authors.forename: M M
authors.initials: MM
authors.lastname: Muñoz-Díaz
authors.forename: M J
authors.initials: MJ
authors.lastname: Fernández-Aceñero
authors.forename: P
authors.initials: P
authors.lastname: Salvadores
authors.forename: J
authors.initials: J
authors.lastname: Schneider
mesh_terms: D001943:Breast Neoplasms / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000145:classification* / Q000378:metabolism / Q000473:pathology; D018572:Disease-Free Survival; D005260:Female; D006801:Humans; D009367:Neoplasm Staging; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000096:biosynthesis; D011980:Receptors, Progesterone / Q000096:biosynthesis; D012189:Retrospective Studies
chemical_list: D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone