Overexpression of (P) RR, which may contribute to cancer initiation and progression via the Wnt/β-catenin, RAS, MAPK/ERK and PI3K/AKT/mTOR pathways as well as V-ATPase function, has been observed in various cancers including pancreatic, brain, colorectal, endometrial, breast and adrenal cancers (Table 2). This evidence concerns the gene MTOR and cancer.