4E-binding protein 1, a cell signaling hallmark in breast cancer that correlates with pathologic grade and prognosis.
Clin Cancer Res
; 13(1): 81-9, 2007 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-17200342
ABSTRACT
PURPOSE:
Cell signaling pathways include a complex myriad of interconnected factors from the membrane to the nucleus, such as erbB family receptors and the phosphoinositide-3-kinase/Akt/mTOR and Ras-Raf-ERK cascades, which drive proliferative signals, promote survival, and regulate protein synthesis. EXPERIMENTALDESIGN:
To find pivotal factors in these pathways, which provide prognostic information in malignancies, we studied 103 human breast tumors with an immunohistochemical profile, including total and phosphorylated (p) proteins human epidermal growth factor receptor 2 (HER2), epidermal growth factor receptor, extracellular signal-regulated kinase 1/2, Akt, 4E-binding protein 1 (4EBP1), eukaryotic initiation factor 4E, phosphorylated ribosomal protein S6 kinase 1, phosphorylated ribosomal protein S6, and Ki67. Western blot and reverse lysate protein arrays were also done in a subset of tumors.RESULTS:
Significantly, activation of the phosphoinositide-3-kinase/Akt/mTOR cascade was detected in a high proportion of tumors (41.9%). Tumors with HER2 overexpression showed higher p-Akt as compared with negative tumors (P < 0.001). Levels of p-Akt correlated with the downstream molecules, p-4EBP1 (P = 0.001) and p-p70S6K (P = 0.05). Although 81.5% of tumors expressed p-4EBP1, in 16.3% of these tumors, concomitant activation of the upstream factors was not detected. Interestingly, p-4EBP1 was mainly expressed in poorly differentiated tumors (P < 0.001) and correlated with tumor size (P < 0.001), presence of lymph node metastasis (P = 0.002), and locoregional recurrences (P = 0.002). Coexpression of p-4EBP1 and p-eIF4G correlated with a high tumor proliferation rate (P = 0.012).CONCLUSION:
In this study, p-4EBP1 was the main factor in signaling pathways that associate with prognosis and grade of malignancy in breast tumors. Moreover, p-4EBP1 was detected in both HER2-positive and HER2-negative tumors. This factor seems to be a channeling point at which different upstream oncogenic alterations converge and transmit their proliferative signal, modulating protein translation.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fosfoproteínas
/
Prognóstico
/
Neoplasias da Mama
/
Transdução de Sinais
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Regulação Neoplásica da Expressão Gênica
/
Proteínas Adaptadoras de Transdução de Sinal
Tipo de estudo:
Prognostic_studies
Limite:
Adult
/
Aged
/
Female
/
Humans
/
Middle aged
Idioma:
En
Revista:
Clin Cancer Res
Assunto da revista:
NEOPLASIAS
Ano de publicação:
2007
Tipo de documento:
Article
País de afiliação:
Espanha