Independent prognostic value of the basal-like phenotype of breast cancer and associations with EGFR and candidate stem cell marker BMI-1.
OBJECTIVE
To study the relationship between basal-like breast cancers, epidermal growth factor receptor (EGFR) and candidate stem cell markers (BMI-1, EZH2, Oct-4) in a population-based setting.


RESULTS
Immunohistochemistry was evaluated in a series of 190 breast cancers. Basal-like phenotype (BLP) 1-5 was found in 4.3-14.3% of cases. EGFR was expressed in 9% of cases and associated with cytokeratin (CK) 5 and P-cadherin positivity, but not with survival; 28% of CK5+ cases were EGFR+. On multivariate analysis, basal-like differentiation and lymph node status were independent prognostic factors of comparable strength. BMI-1 positivity (42.6%) was associated with absence of basal-like features, oestrogen receptor positivity and low Ki67, but not related to survival. BMI was not associated with EZH2 expression, and these markers tended to show opposite associations with other variables, suggesting different roles in breast cancer. Oct-4 expression was not detected in this series.


CONCLUSIONS
Basal-like features and lymph node status were strong and independent prognostic factors in this population-based series of breast cancer. Neither EGFR nor BMI-1 had significant prognostic impact, whereas EZH2 expression was associated with decreased survival. BMI-1 was inversely related to basal-like factors, and a stem cell phenotype of the basal-like subgroup could not be verified by this marker.
Arnes
J B
JB
The Gade Institute, Section for Pathology, University of Bergen, Haukeland University Hospital, Bergen, Norway.
Collett
K
K
Akslen
L A
LA
D000368:Aged; D014408:Biomarkers, Tumor / Q000378:metabolism; D001943:Breast Neoplasms / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D018270:Carcinoma, Ductal, Breast / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D004268:DNA-Binding Proteins / Q000378:metabolism; D066246:ErbB Receptors / Q000378:metabolism*; D005260:Female; D006801:Humans; D008408:Mastectomy; D008875:Middle Aged; D018295:Neoplasms, Basal Cell / Q000175:diagnosis* / Q000378:metabolism / Q000401:mortality; D009687:Nuclear Proteins / Q000378:metabolism*; D050814:Octamer Transcription Factor-3 / Q000378:metabolism; D010641:Phenotype; D063150:Polycomb Repressive Complex 1; D011379:Prognosis; D011518:Proto-Oncogene Proteins / Q000378:metabolism*; D012097:Repressor Proteins / Q000378:metabolism*; D015996:Survival Rate; D035165:Transcription Factors, General
C069077:BMI1 protein, human; D014408:Biomarkers, Tumor; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D050814:Octamer Transcription Factor-3; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D035165:Transcription Factors, General; C524849:ZNF467 protein, human; D063150:Polycomb Repressive Complex 1; C512478:EGFR protein, human; D066246:ErbB Receptors