VEGFA and hepatocellular carcinoma: Apart from distinct cells contribute to the HCC metastasis, many kinds of noncellular components of tumor microenvironment have participated in the tumor metastasis, such as TGF-b [34], vascular endothelial growth factor [35, 36], epidermal growth factor [37], and MMPs [38, 39], E-cadherin [40], so on.