Phosphorylated mTOR expression as a predictor of survival after liver resection for colorectal liver metastases.

Background Phosphorylated mammalian target of rapamycin (p-mTOR) plays a crucial role in the process of cancer progression. Common gene mutations of colorectal cancer lead to the activation of the PI3k/Akt/mTOR pathway. In this study, we determined whether p-mTOR expression in colorectal liver metastases is a predictive marker of prognosis following liver resection. Methods Eighty-one patients with colorectal liver metastases who had undergone curative resection were evaluated using immunohistochemistry of p-mTOR. Data regarding clinicopathological features and patient survival were analyzed. Results The p-mTOR expression in colorectal liver metastases was detected in 55 (67.9%) patients. Patients whose metastases had high p-mTOR expression showed a significantly lower overall survival rate after resection as compared to patients with low p-mTOR expression (p = 0.016), while there was no significant difference in the disease-free survival between the two groups. Repeat resection for recurrence was performed more frequently in patients with p-mTOR positive than others (p = 0.024). Multivariate analysis showed that p-mTOR expression was an independent prognostic factor of overall survival after liver resection (p = 0.019). Conclusions mTOR was frequently activated in colorectal liver metastases, and the p-mTOR expression was a biological marker for predicting the overall survival of patients with colorectal liver metastases following liver resection.