title: Basal-like breast carcinoma: from expression profiling to routine practice.
abstract: BACKGROUND
  Advances in the understanding of the molecular and genetic mechanisms of breast cancer have led to realization of the heterogeneity of the disease and the promise of a new era of individualized management for patients with breast cancer. The advent and use of high-throughput molecular methods for the study of breast cancer have brought to the forefront the existence of the so-called basal-like breast cancers, which have been shown to have distinct biologic and clinical characteristics.
  
  
  OBJECTIVE
  To critically assess the clinicopathologic features of basal-like breast cancer, discuss the morphologic and immunophenotypic features of basal-like cancer, and explore the criteria that can be used to identify these tumors in routine practice.
  
  
  METHODS
  A Medline/PubMed search was conducted using the terms "basal-like," "(basal OR basaloid OR basal-like) AND breast cancer." All articles in English language were retrieved and critically reviewed.
  
  
  CONCLUSIONS
  Basal-like breast cancers constitute a distinct, yet heterogeneous, class of neoplasms associated with specific histologic features and poor prognosis despite high response rates to neoadjuvant chemotherapy. Basal-like breast cancers have features that recapitulate those of tumors arising in BRCA1 mutation carriers, and the majority of patients with BRCA1 germline mutations develop basal-like breast cancers. At the molecular level, basal-like cancers harbor a transcriptome that is distinct from that of hormone-receptor-positive or HER2-amplified tumors, being characterized by the expression of genes usually found in basal/myoepithelial cells of the breast. However, translating the new concepts about basal-like cancer into clinical practice has proven a Herculean task, given the lack of an internationally accepted definition for these tumors and for the method of identification in routine practice.
authors.affiliation: Department of Histopathology, Nottingham City Hospital NHS Trust, Nottingham University, Nottingham, UK.
authors.forename: Emad
authors.initials: E
authors.lastname: Rakha
authors.forename: Jorge S
authors.initials: JS
authors.lastname: Reis-Filho
mesh_terms: D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016130:Immunophenotyping; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor