Phosphorylated mammalian target of rapamycin is associated with an adverse outcome in oral squamous cell carcinoma

Objectives. To evaluate the expression of phosphorylated mammalian target of rapamycin (p-mTOR) and phosphatase and tensin homolog deleted on chromosome TEN (PTEN) in oral squamous cell carcinomas (OSCCs) and relate them with clinicopathologic characteristics and outcome. Study Design. We analyzed p-mTOR and PTEN protein expression by immunohistochemistry in 72 OSCCs. Multivariate analysis was conducted to examine their role in survival. Results. p-mTOR expression was observed in 46 (63.9%) cancers and PTEN expression was absent in 22 (30.6%). An adverse independent prognostic value for high p-mTOR expression was found (P = .043) as well as for advanced tumor stage (P = .010) in patients' overall survival (OS). For disease-free survival (DFS), only advanced tumor stage (P = .001) presented an adverse independent prognostic value. Conclusions. The effect of p-mTOR in OS of OSCC suggests that this marker may serve as a reliable biological marker to identify high-risk subgroups and as a guide to therapy. Furthermore, the high expression of p-mTOR suggests that this protein may be a promising therapeutic target in OSCC.