Y-box-binding protein 1 (YB1) in breast carcinomas: relation to aggressive tumor phenotype and identification of patients at high risk for relapse.
OBJECTIVE
To investigate the expression pattern of Y-box-binding protein 1 (YB1) in breast carcinomas, its clinicopathological and prognostic value, and its association with the breast cancer stem cell phenotype [CD44(+)/CD24(-/low)].


RESULTS
Immunohistochemistry was performed on 225 paraffin embedded specimens of invasive breast carcinomas to detect the expression of the proteins YB1, ER, PR, HER2, p53, Ki67, bcl-2, CD44 and CD24. YB1 protein was detected in the nuclei, the cytoplasm and the stroma of the tumor cells. Cytoplasmic YB1 was detected more often in carcinomas of ductal type (p = 0.002), of higher nuclear grade (p < 0.001), with lack of ER expression (p = 0.002), positive expression of p53 and Ki67 (p = 0.002 and p = 022, respectively), and with present CD44(+)/CD24(-/low) breast cancer stem cells (p = 0.001), while its association with bcl-2 was found to be inverse (p = 0.042). Nuclear YB1 was found to exert unfavorable impact on the disease-free survival of the unselected patients (p = 0.05) and the patients having been subjected to adjuvant chemotherapy and radiotherapy (p = 0.036 and p = 0.05, respectively).


CONCLUSIONS
Cytoplasmic YB1 is associated with an aggressive and "stem cell-like" tumor phenotype, while nuclear localization discriminates patients at high risk for recurrence, especially those who are subjected to chemo- and radiotherapy.
5th Department of Internal Medicine, Evagelismos Hospital, Athens, Greece.
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Mylona
1st Department of Pathology, Medical School, University of Athens, 75 Mikras Asias Str., Goudi, GR-11527 Athens, Greece.
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Melissaris
1st Department of Pathology, Medical School, University of Athens, 75 Mikras Asias Str., Goudi, GR-11527 Athens, Greece.
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Giannopoulou
1st Department of Pathology, Medical School, University of Athens, 75 Mikras Asias Str., Goudi, GR-11527 Athens, Greece.
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Theohari
Department of Clinical Therapeutics, Alexandra General Hospital, Medical School, University of Athens, Athens, Greece.
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Papadimitriou
Department of Clinical Therapeutics, Alexandra General Hospital, Medical School, University of Athens, Athens, Greece.
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Keramopoulos
1st Department of Pathology, Medical School, University of Athens, 75 Mikras Asias Str., Goudi, GR-11527 Athens, Greece. Electronic address: lnako@med.uoa.gr.
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Nakopoulou
D000328:Adult; D000368:Aged; D001707:Biopsy, Needle; D001943:Breast Neoplasms / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D018270:Carcinoma, Ductal, Breast / Q000235:genetics* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D015331:Cohort Studies; D003593:Cytoplasm / Q000378:metabolism / Q000473:pathology; D004268:DNA-Binding Proteins / Q000235:genetics; D018572:Disease-Free Survival; D005260:Female; D005500:Follow-Up Studies; D015972:Gene Expression Regulation, Neoplastic; D006115:Greece; D006785:Hospitals, University; D006801:Humans; D007150:Immunohistochemistry; D008875:Middle Aged; D009364:Neoplasm Recurrence, Local / Q000235:genetics* / Q000401:mortality / Q000473:pathology; D014411:Neoplastic Stem Cells / Q000378:metabolism / Q000473:pathology; D010641:Phenotype; D012189:Retrospective Studies; D018570:Risk Assessment; D016019:Survival Analysis; D051840:Y-Box-Binding Protein 1 / Q000235:genetics*
D004268:DNA-Binding Proteins; D051840:Y-Box-Binding Protein 1
Breast cancer; Chemotherapy; Immunohistochemistry; Radiotherapy; Recurrence-free survival; Y-box-binding protein