PIK3CD and colorectal carcinoma: In this study, we report that miR-422a is down‐regulated in CRC tissues and cell lines; ectopic expression of miR-422a inhibits cell proliferation and tumor growth ability, inhibition of endogenous miR-422a, by contrast, promotes cell proliferation and tumor growth ability of CRC cells; miR-422a directly targets 3′-UTR of the AKT1 and MAPK1, down-regulation of miR-422a led to the activation of Raf/MEK/ERK and PI3K/AKT signaling pathways to promote cell proliferation in CRC.