title: New molecular classifications of breast cancer.
abstract: Traditionally, pathologic determinations of tumor size, lymph node status, endocrine receptor status, and human epidermal growth factor receptor 2 (HER2) status have driven prognostic predictions and adjuvant therapy recommendations for patients with early stage breast cancer. However, these prognostic and predictive factors are relatively crude measures, resulting in many patients being overtreated or undertreated. As a result of gene expression assays, there is growing recognition that breast cancer is a molecularly heterogeneous disease. Evidence from gene expression microarrays suggests the presence of multiple molecular subtypes of breast cancer. The recent commercial availability of gene expression profiling techniques that predict risk of disease recurrence as well as potential chemotherapy benefit have shown promise in refining clinical decision making. These techniques will be reviewed in this article.
authors.affiliation: Division of Hematology/Oncology, Northwestern University, Feinberg School of Medicine, Robert H. Lurie Comprehensive Cancer Center, Chicago, IL 60611, USA. m-cianfrocca@northwestern.edu
authors.forename: Mary
authors.initials: M
authors.lastname: Cianfrocca
authors.forename: William
authors.initials: W
authors.lastname: Gradishar
mesh_terms: D001943:Breast Neoplasms / Q000145:classification* / Q000175:diagnosis / Q000235:genetics / Q000473:pathology; D003362:Cost-Benefit Analysis; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D025202:Molecular Diagnostic Techniques / Q000191:economics; D020411:Oligonucleotide Array Sequence Analysis / Q000191:economics; D011379:Prognosis; D020133:Reverse Transcriptase Polymerase Chain Reaction