It showed that CTCF was overexpressed in CRC cells compared with FHC cells (Additional file Fig. S2C), and the effect of si-CTCF showed in Additional file Fig. S2D. Furthermore, the results of RT-qPCR were observed that when CTCF was knockdown, the level of SPARC pre-mRNA, SPARC mRNA and circSPARC decreased all (Fig. 3I). Here, SPARC is linked to colorectal carcinoma.