MMP13 and hepatocellular carcinoma: Previous studies involving human HCC MHCC97L and BEL-7404 cells suggested that PPARγ overexpression suppressed cell migration and invasion by down-regulating matrix metalloproteinase (MMP) 9, MMP13, and heparanase (HPSE) expression, while up-regulating E-cadherin and tissue inhibitor of metalloproteinase (TIMP) 3 expression [11].