MTOR and ulcerative colitis: Chronic oxidative stress and inflammation mediate the activation of multiple different downstream signaling pathways such as the NF-κB, AP-1 and mammalian target of rapamycin (mTOR), Ras, and Wnt pathways, which are implicated in the development of major GI disorders such as gastric ulcer, ulcerative colitis, gastric cancer, and colorectal cancer [13,14,15,16].