Clinical Significance of mTOR and p-mTOR Protein Expression in Human Colorectal Carcinomas

Aim: To investigate the significance of mammalian target of rapamycin (mTOR) and its active form, p-mTOR in colorectal carcinomas. Methods: Immunohistochemistry was used to detect the expression of mTOR and p-mTOR proteins in 108, 40 and 40 tissue samples from colorectal carcinoma, normal colonic mucosa and adenomatous polyps samples, respectively. The correlation of mTOR and p-mTOR expression with clinicopathological characteristics of colorectal carcinoma was analyzed. Results: The positive rates of mTOR and p-mTOR were significantly higher in colorectal carcinoma (61.1% and 61.1%, respectively, p<0.05) than in normal colonic mucosa (7.5% and 2.5%) and adenomatous polyps (27.5% and 20%). Overexpression of total mTOR protein was significantly associated with T1/T2 stage tumors, lymph node metastasis, distal metastasis) and degree of differentiation. p-mTOR overexpression was additionaly linked with degree of differentiation and TNM stage. Conclusion: The overexpression of mTOR and p-mTOR may play important roles in colorectal carcinogenesis with relations to the degree of differentiation, invasiveness and metastasis.