title: Molecular Testing in Breast Cancer: A Guide to Current Practices.
abstract: BACKGROUND
  -Molecular diagnostics play a role in the management of many cancers, including breast cancer.
  
  
  OBJECTIVE
  -To provide an update on molecular testing in current clinical practice, targeted at practicing pathologists who are not breast cancer specialists.
  
  
  METHODS
  -This study is a narrative literature review.
  
  
  CONCLUSIONS
  -In addition to routine hormone (estrogen and progesterone) receptor testing, new and recurrent tumors are tested for HER2 amplification by in situ hybridization or overexpression by immunohistochemistry. Intrinsic subtyping of tumors represents a fundamental advance in our understanding of breast cancer biology, but currently it has an indirect role in patient management. Clinical next-generation sequencing (tumor profiling) is increasingly used to identify potentially actionable mutations in tumor tissue. Multianalyte assays with algorithmic analysis, including MammaPrint, Oncotype DX, and Prosigna, play a larger role in breast cancer than in many other malignancies. Given that a proportion of breast cancers are familial, testing of nontumor tissue for cancer predisposition mutations also plays a role in breast cancer care.
authors.affiliation: From the Department of Pathology and Immunology, Washington University School of Medicine, St Louis, Missouri. Presented at the 2nd Princeton Integrated Pathology Symposium: Breast Pathology; February 8, 2015; Plainsboro, New Jersey.
authors.forename: Ian S
authors.initials: IS
authors.lastname: Hagemann
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics* / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000235:genetics / Q000378:metabolism; D005260:Female; D020022:Genetic Predisposition to Disease / Q000235:genetics; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D009154:Mutation; D017410:Practice Guidelines as Topic; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D011987:Receptors, Steroid / Q000378:metabolism
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011987:Receptors, Steroid