Association between high expression of phosphorylated Akt and mammalian target of rapamycin and improved survival in salivary gland adenoid cystic carcinoma

Abstract

Background: Previous genomic studies revealed phosphotidylinositol‐3‐kinase (PI3K)/Akt pathway mutation in human salivary gland adenoid cystic carcinoma (ACC). No validation of its prognostic value has been reported.

Methods: P‐Akt, pan‐Akt, phosphorylated‐mammalian target of rapamycin (p‐mTOR), PI3K, and insulin‐like growth factor‐1 receptor beta (IGF‐1Rβ) were detected on 120 salivary gland ACC/adjacent salivary gland pairs immunohistochemically and were correlated with clinicopathological data.

Results: Expression of cytoplasmic and nuclear p‐Akt, cytoplasmic p‐mTOR, nuclear pan‐Akt, and nuclear IGF‐1Rβ were higher in ACC than in adjacent salivary glands. P‐Akt, p‐mTOR, PI3K, and IGF‐1Rβ expression were correlated with one another in both cytoplasm and nucleus. Low p‐mTOR expression in both subcellular compartments was associated with locoregional recurrence, poor disease‐free survival (DFS), and overall survival (OS). Low nuclear p‐Akt (Ser473) and p‐mTOR expression were independent predictors for poor OS and DFS, respectively.

Conclusion: High level of Akt/mTOR activation in ACC is correlated with a significantly improved survival. P‐mTOR and nuclear p‐Akt are prognostic biomarkers of salivary gland ACC. © 2017 Wiley Periodicals, Inc. Head Neck 39: 1145–1154, 2017