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. The gene discussed is STAT3; the disease is colorectal carcinoma.