To examine if OPN was involved in the regulation of DNA methylation, we performed MeDIP-sequencing (MeDIP-seq) assay in HCC tissues, and found an increasing tendency in 5-methylcytosine (5mC) differentially modified peaks in HCCs with high OPN expression than that of low-OPN ones (Fig. 2a). Here, SPP1 is linked to hepatocellular carcinoma.