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Cancer. 2013 Oct 1;119(19):3504-13. doi: 10.1002/cncr.28255. Epub 2013 Jul 16.

Prognostic impact of the activation status of the Akt/mTOR pathway in synovial sarcoma.

Author information

1
Department of Anatomic Pathology, Graduate School of Medical Science, Kyushu University, Fukuoka, Japan.

Abstract

BACKGROUND:

The Akt/mammalian target of rapamycin (mTOR) pathway, downstream from phosphatidylinositol 3-kinase (PI3K), mediates cell survival and proliferation. Although this pathway reportedly contributes to the progression of synovial sarcoma, its prognostic impact has not been clarified.

METHODS:

The authors analyzed clinicopathologic data and phosphorylation status of Akt (a serine/threonine kinase also known as protein kinase B), mTOR, the eukaryotic translation initiation factor 4E binding protein (4E-BP1), and the S6 ribosomal protein by immunohistochemical analysis of 120 formalin-fixed, paraffin-embedded samples and by Western blot analysis of 24 frozen samples from 112 patients with synovial sarcoma.

RESULTS:

Akt, mTOR, 4E-BP1, and S6 were activated in 76.5%, 67.6%, 59.6%, and 42.6% of samples, respectively. Immunohistochemically positive phosphorylated (p) mTOR (pmTOR) and p4E-BP1 results were correlated with higher mitotic activity, and positive p4E-BP1 results were correlated with greater necrosis. No mutations around the hot spots in the PI3K catalytic subunit α (PI3KCA) and Akt1 genes were observed. In multivariate analysis of clinicopathologic parameters, frequent mitosis was a risk factor for shorter overall survival; and male sex, visceral location, larger tumor size, and frequent mitosis were identified as risk factors for shorter event-free survival. Positive pmTOR and p4E-BP1 results were correlated significantly with shorter overall survival, and positive p4E-BP1 results were correlated with shorter event-free survival in univariate analysis. Positive pAkt results were associated significantly with shorter event-free survival in multivariate analysis.

CONCLUSIONS:

In this study, the Akt/mTOR pathway was activated and was associated with worse clinical and pathologic behavior in patients with synovial sarcoma. The authors propose that this pathway may have potential as a therapeutic target.

KEYWORDS:

Akt; mammalian target of rapamycin; mutation; prognosis; synovial sarcoma

PMID:
23861137
DOI:
10.1002/cncr.28255
[Indexed for MEDLINE]
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