Under the action of p53, the expression of miRNA-34a increases, thus inhibiting the expression of FOSL1 and indirectly inhibiting the activity of MMP-1 and MMP-9, which causes the contents of MMP-1 and MMP-9 in colon cancer cells decrease, thus inhibiting the migration and metastasis of tumor cells (71). The gene discussed is MMP9; the disease is malignant colon neoplasm.