To further explore the functional roles of SLC22A7 in HCC metastasis, we overexpressed SLC22A7 in MHCC97H cells, and found that SLC22A7 overexpression significantly decreased the invasive ability of MHCC97H cells and reduced the activity of matrix metalloproteinase-9 (MMP9), suggesting that SLC22A7 might prevent HCC invasion by inhibiting MMP9 activity. The gene discussed is MMP9; the disease is hepatocellular carcinoma.