title: Immunophenotyping of male breast cancer.
abstract: OBJECTIVE
  Male breast cancer is a rare disease, and knowledge of carcinogenesis is limited. Conflicting results, based on small series, have been reported for clinically relevant biomarkers.
  
  
  RESULTS
  One hundred and thirty-four cases of male breast cancer were immunohistochemically stained on tissue microarrays for oestrogen receptor (ER), progesterone receptor (PR), androgen receptor, human epidermal growth factor receptor 2 (HER2), BRST2, cyclin D1, bcl-2, p53, p16, p21, Ki67, cytokeratin (CK) 5/6, CK14, and epidermal growth factor receptor. Data were correlated with clinicopathological features and patient outcome. High mitotic count and high grade were correlated with high Ki67, HER2 amplification/overexpression, p53 accumulation, high p21 expression, low PR expression, and low bcl-2 expression. PR negativity (P=0.009) and p53 accumulation (P=0.042) were correlated with decreased 5-year survival and were independent markers for patient outcome in Cox regression. In unsupervised hierarchical clustering, four groups were identified that were correlated with distinctive clinicopathological features. The hormone negative/ER-positive/high-grade cluster was significantly associated with decreased survival (P=0.011) and was an independent prognostic factor in Cox regression.
  
  
  CONCLUSIONS
  Several tissue biomarkers are associated with an aggressive phenotype in male breast cancer. PR and p53 are the most promising individual prognostic markers. On the basis of immunophenotype, four distinctive and prognostically relevant male breast cancer groups were identified, indicating that protein expression profiling may be clinically useful in male breast cancer.
authors.affiliation: Department of Pathology, University Medical Centre Utrecht, Utrecht, The Netherlands.
authors.forename: Robert
authors.initials: R
authors.lastname: Kornegoor
authors.forename: Anoek H J
authors.initials: AH
authors.lastname: Verschuur-Maes
authors.forename: Horst
authors.initials: H
authors.lastname: Buerger
authors.forename: Marieke C
authors.initials: MC
authors.lastname: Hogenes
authors.forename: Peter C
authors.initials: PC
authors.lastname: de Bruin
authors.forename: Joost J
authors.initials: JJ
authors.lastname: Oudejans
authors.forename: Bernd
authors.initials: B
authors.lastname: Hinrichs
authors.forename: Paul J
authors.initials: PJ
authors.lastname: van Diest
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000378:metabolism*; D018567:Breast Neoplasms, Male / Q000175:diagnosis / Q000378:metabolism* / Q000401:mortality; D049109:Cell Proliferation; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D016130:Immunophenotyping; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D011980:Receptors, Progesterone / Q000378:metabolism*; D012044:Regression Analysis; D012189:Retrospective Studies; D015996:Survival Rate; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*
chemical_list: D014408:Biomarkers, Tumor; D011980:Receptors, Progesterone; D016159:Tumor Suppressor Protein p53