PDCD4 and colorectal carcinoma: MiR-21-5p may be activated by the phosphatidylinositol-3-kinase (PI3K), signal transducer and activator of transcription 3 (STAT3), and programmed cell death factor 4/tumor necrosis factor-α (PDCD4/TNF-α) signaling pathways, which affect inflammatory processes and tumor progression in CRC [32].