title: Prognostic relevance of basal cytokeratin expression in operable breast cancer.
abstract: OBJECTIVE
  We investigated whether basal cytokeratin (CK5/6 or CK17) expression had an impact on survival in patients with operable breast cancer.
  
  
  METHODS
  Expression of CK5/6 or CK17 was analyzed by immunohistochemistry in 195 women with breast cancer.
  
  
  RESULTS
  In total, 72 (37%) tumor samples were regarded as being positive for CK5/6 or CK17. The basal-like phenotype as defined by basal cytokeratin expression, lack of estrogen receptor (ER) and absence of HER2 overexpression was found in 48 (25%) cases. Positive staining for CK5/6 or CK17 was associated with worse prognosis when compared with patients negative for basal cytokeratins in all cases (5-year cancer-specific survival rate 59.4 vs. 77.5%, p = 0.0273) and in the node-negative group (70.5 vs. 90.8%, p = 0.0208) but not in the node-positive group (43.9 vs. 65.4%, p = 0.1182). To determine the real prognostic value of basal cytokeratins, survival in a group of ER-negative patients was analyzed depending on CK5/6 or CK 17 expression. No influence on survival was observed. The outcome of patients whose cancers were positive for cyclin E regardless of ER status was not changed by CK5/6 or CK17 expression. In multivariate analysis, independent prognostic factors affecting survival in the whole group included: nodal involvement, HER2 status and cyclin E expression. Neither ER status nor basal cytokeratin expression retained statistical significance.
  
  
  CONCLUSIONS
  We demonstrated that the poor prognosis associated with the basal-like phenotype of breast cancer was determined by ER absence and cyclin E expression and not by CK5/6 or CK17 expression.
authors.affiliation: Department of Chemotherapy, Copernicus Memorial Hospital, Lodz, Poland. piotrpo@mp.pl
authors.forename: Piotr
authors.initials: P
authors.lastname: Potemski
authors.forename: Renata
authors.initials: R
authors.lastname: Kusinska
authors.forename: Cezary
authors.initials: C
authors.lastname: Watala
authors.forename: Elzbieta
authors.initials: E
authors.lastname: Pluciennik
authors.forename: Andrzej K
authors.initials: AK
authors.lastname: Bednarek
authors.forename: Radzislaw
authors.initials: R
authors.lastname: Kordek
mesh_terms: D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000032:analysis*; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology / Q000601:surgery*; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry* / Q000473:pathology / Q000601:surgery*; D018572:Disease-Free Survival; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D007633:Keratins / Q000032:analysis*; D008207:Lymphatic Metastasis; D008875:Middle Aged; D015999:Multivariate Analysis; D010641:Phenotype; D011237:Predictive Value of Tests; D011379:Prognosis; D011960:Receptors, Estrogen / Q000032:analysis; D016019:Survival Analysis
chemical_list: D014408:Biomarkers, Tumor; D011960:Receptors, Estrogen; D007633:Keratins