SPP1 and neoplasm: Interestingly, spp1, which encodes OPN, a secreted phosphoprotein that plays a crucial role in HCC metastasis [14–17], was also significantly upregulated in HCC with CCN2 overexpression, whereas CDH1, which encodes E-cadherin and mediates the epithelial phenotype in tumor cells [18], was significantly downregulated.