CDK6 and colorectal cancer: Previous studies have shown that the increased expression of miR-449 causes down-regulation of oncogene CDK6 which stimulates cell proliferation in gastric cancer [58], miR-448 suppresses proliferation and invasion by regulating IGF1R in colorectal cancer cells [59], and miR-378 family members target IGF1R, a key signaling molecule in rhabdomyosarcoma [60].