title: Utility of estrogen receptor, progesterone receptor, and HER-2/neu analysis of multiple foci in multifocal ipsilateral invasive breast carcinoma.
abstract: OBJECTIVE
  To determine the frequency of estrogen receptor (ER), progesterone receptor (PR), and HER-2/neu (HER2) testing multiple foci of ipsilateral invasive breast carcinoma at our institution and to evaluate resulting change in treatment recommendation.
  
  
  METHODS
  We identified 165 consecutive cases of multifocal invasive breast cancer over a 10-year period (2005-2014). Clinicopathologic features and treatment recommendation were assessed by slide and chart review.
  
  
  RESULTS
  Seventy (42.4%) of 165 patients had two or more foci tested. In the first 6 years (2005-2010), frequency of testing two or more foci was 31.6% and increased to 70.6% in 2014. Seven (10%) of 70 had a clinically significant difference in ER/PR and/or HER2 status, five (7.1%) with a difference in HER2, one (1.4%) in ER/PR, and one (1.4%) in both ER/PR and HER2. All cases with difference in status had different histology and/or the largest focus was the most positive one.
  
  
  CONCLUSIONS
  Our findings support current recommendations to evaluate additional smaller tumor foci in multifocal invasive breast cancer if the focus is of different grade or histology. Additional features, including specific histology, grade, and ER, PR, and HER2 status of the largest focus, should also be considered when selecting cases for which testing of additional foci may be of benefit.
authors.affiliation: From the Department of Pathology and.
authors.forename: Ellen G
authors.initials: EG
authors.lastname: East
authors.affiliation: From the Department of Pathology and.
authors.forename: Judy C
authors.initials: JC
authors.lastname: Pang
authors.affiliation: Biostatistics, University of Michigan, Ann Arbor.
authors.forename: Kelley M
authors.initials: KM
authors.lastname: Kidwell
authors.affiliation: From the Department of Pathology and jjorns@umich.edu.
authors.forename: Julie M
authors.initials: JM
authors.lastname: Jorns
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000473:pathology*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009378:Neoplasms, Multiple Primary / Q000473:pathology*; D018719:Erb-b2 Receptor Tyrosine Kinases / Q000032:analysis / Q000096:biosynthesis; D011960:Receptors, Estrogen / Q000032:analysis / Q000096:biosynthesis; D011980:Receptors, Progesterone / Q000032:analysis / Q000096:biosynthesis
chemical_list: D014408:Biomarkers, Tumor; D018719:Erb-b2 Receptor Tyrosine Kinases; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; C508053:ERBB2 protein, human
keywords: Breast; Cancer; Carcinoma; ER; Estrogen receptor; HER-2/neu; Multifocal; PR; Progesterone receptor