title: Metaplastic Breast Cancer: Molecular Typing and Identification of Potential Targeted Therapies at a Single Institution.
abstract: Metaplastic breast carcinoma (MBC) is a rare and aggressive histologic subtype of breast cancer comprising approximately 0.5% to 5.0% of all invasive breast cancers with a poor prognosis and limited therapeutic options.
  
  
  
  We investigated MBC at our institution to evaluate outcomes and investigate the molecular profile of our cohort to determine the presence of mutations for which there are targeted therapies.
  
  
  
  We found our cohort to consist mainly of the matrix-producing variant (72%) with 48% having the stereotypical estrogen receptor-negative/progesterone receptor-negative/human epidermal growth factor receptor-2-negative phenotype. While the overall survival of our cohort was an average of 1679 days (4.6 years), we had a surprising number of patients with second primaries (40%) and distant metastases (40%), yet few recurrences (12%). Molecular analysis of the tumors indicated that one gene mutation, CSFIR, was significantly associated with outcome (P = .021); however, the cohort was defined by frequent mutations in ERBB4 (36%), PIK3CA (48%), and FLT3 (60%), for which there are now targeted therapies.
  
  
  
  While surgery is the appropriate first step in the management of this aggressive malignancy, the collection of data pertaining to the use of targeted agents, although anecdotal, may provide clues to better treatment for these patients.
authors: Department of Biochemistry, Dickinson College, Dickinson, PA.
authors: Jessica
authors: J
authors: Edenfield
authors: Pathology Associates, Greenville, SC. Electronic address: schammelph.d@ghs.org.
authors: Christine
authors: C
authors: Schammel
authors: Medical University of South Carolina, Charleston, SC.
authors: Justin
authors: J
authors: Collins
authors: Pathology Associates, Greenville, SC.
authors: David
authors: D
authors: Schammel
authors: Institute for Translational Oncologic Research, Greenville, SC.
authors: W Jeff
authors: WJ
authors: Edenfield
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics*; D001943:Breast Neoplasms / Q000145:classification* / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D018270:Carcinoma, Ductal, Breast / Q000235:genetics / Q000378:metabolism / Q000556:secondary*; D002294:Carcinoma, Squamous Cell / Q000235:genetics / Q000378:metabolism / Q000556:secondary; D058534:Class I Phosphatidylinositol 3-Kinases / Q000235:genetics; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008207:Lymphatic Metastasis; D008679:Metaplasia / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D060787:Neoplasm Grading; D009361:Neoplasm Invasiveness; D009364:Neoplasm Recurrence, Local / Q000235:genetics / Q000473:pathology*; D009367:Neoplasm Staging; D011379:Prognosis; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000378:metabolism; D066247:Receptor, ErbB-4 / Q000235:genetics; D016184:Receptors, Colony-Stimulating Factor / Q000235:genetics; D011960:Receptors, Estrogen / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism; D012189:Retrospective Studies; D015996:Survival Rate; D051941:fms-Like Tyrosine Kinase 3 / Q000235:genetics
chemical_list: D014408:Biomarkers, Tumor; D058534:Class I Phosphatidylinositol 3-Kinases; D018719:Erb-b2 Receptor Tyrosine Kinases; D066247:Receptor, ErbB-4; D016184:Receptors, Colony-Stimulating Factor; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D051941:fms-Like Tyrosine Kinase 3; C484760:PIK3CA protein, human; C508053:ERBB2 protein, human; C587689:ERBB4 protein, human; C497970:FLT3 protein, human
keywords: Distant metastases; Genetic profiling; Novel therapy for poor prognosis; Rare breast cancer; Second primaries