In the current study, luciferase and qRT-PCR assays also confirm that PIAS3 is a direct target of miR-18a, and up-regulation of miR-18a enhances STAT3-mediated gene expression by regulating the expression of PIAS3. To further confirm the role of PIAS3 as a miRNA-18a “sponge”, we observed that down-regulated CASC2 leads to decreased in PIAS3 mRNA and protein levels, whereas overexpression of CASC2 restores PIAS3 synthesis to high levels in CRC cells. This evidence concerns the gene CASC2 and colorectal carcinoma.