title: Cytokeratin profiles of male breast cancers.
abstract: OBJECTIVE
  The prognostic factors and expression of molecular markers in male breast carcinomas are similar to those in female breast cancers. The identification of distinct cytokeratin (CK) profiles (basal as opposed to luminal cells) helps to identify subsets of tumours with different clinical behaviour. The aim of this study was to investigate CK expression in male breast cancer.
  
  
  RESULTS
  Thirty-two cases of male breast cancer were studied. The panel of CKs studied by immunohistochemistry included: 5/6, 14, 17, 18 and 19. Pathological findings and CK expression were analysed in all cases. Histological patterns included ductal carcinoma in situ, invasive ductal carcinoma and mixed patterns. Four cases were positive for CK5/6 and CK14, identifying a basal-like phenotype. CK17 was negative in all but two cases. All cases expressing either CK5/6 or CK14 were invasive carcinomas of high nuclear and histological grade and were also larger compared with the tumours not expressing CK5/6 and CK14. All tumours except three (also negative for CK5/6) expressed CK18 and CK19. The four basal-like tumours were negative for Her-2 expression.
  
  
  CONCLUSIONS
  Male breast carcinomas have a basal-like phenotype that is similar in frequency to that of female breast carcinomas. The expression of CK5/6 and CK14 identifies a subset of pathologically aggressive male breast cancers.
authors.affiliation: Department of Pathology, Creighton University, Omaha, NE, USA, and UO di Anatomia Patologica, Ospedale di Melegnano, Milan, Italy.
authors.forename: V
authors.initials: V
authors.lastname: Ciocca
authors.forename: A
authors.initials: A
authors.lastname: Bombonati
authors.forename: Z
authors.initials: Z
authors.lastname: Gatalica
authors.forename: M
authors.initials: M
authors.lastname: Di Pasquale
authors.forename: A
authors.initials: A
authors.lastname: Milos
authors.forename: A
authors.initials: A
authors.lastname: Ruiz-Orrico
authors.forename: D
authors.initials: D
authors.lastname: Dreher
authors.forename: N
authors.initials: N
authors.lastname: Folch
authors.forename: F
authors.initials: F
authors.lastname: Monzon
authors.forename: G
authors.initials: G
authors.lastname: Santeusanio
authors.forename: C M
authors.initials: CM
authors.lastname: Perou
authors.forename: P S
authors.initials: PS
authors.lastname: Bernard
authors.forename: J P
authors.initials: JP
authors.lastname: Palazzo
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000032:analysis*; D018567:Breast Neoplasms, Male / Q000378:metabolism* / Q000473:pathology; D018270:Carcinoma, Ductal, Breast / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D007150:Immunohistochemistry; D007633:Keratins / Q000096:biosynthesis*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D011379:Prognosis
chemical_list: D014408:Biomarkers, Tumor; D007633:Keratins