ING4 and colorectal carcinoma: To confirm MMP-2 and COX-2 were the responsive target genes of Sp1 in ING4 regulating CRC angiogenesis, we used siRNA to silence Sp1 expression in the ING4 knocked down p53+/+HCT116 cells, and then collected the conditioned medium to test the impact on angiogenesis in vitro.