The entry of the circulating CSC-regulating miRNAs into the cancer cells could potentially activate or inhibit various oncogenic signaling pathways, such as the PI3K/AKT/mTOR [95,104,105] and WNT signaling pathway [94,100], and this would eventually affect cancer cell proliferation, invasion, and metastasis [95,96,111,112]. This evidence concerns the gene MTOR and cancer.