FOXO3 and colorectal carcinoma: Recent studies have demonstrated that a positive feedback loop that linked miR-155 with the transcription factor NF-κB, inhibition of miR-155 additionally enhanced the sensitivity of CRC cells to 5-FU chemotherapy [45], miR-155 and its target gene FOXO3a acquired radio-resistance via the PI3K/Akt pathway in CRC cell line, which promised miR-155 as a novel specific biomarker to distinguish radio-sensitive from radio-resistant CRC tumors [46].