MMP9 and neoplasm: Further examination of the protein expression of matrix metalloproteinases 9 (MMP-9) and 2 (MMP-2) showed that the protein expression levels of MMP-9 and MMP-2 were significantly increased after overexpression of the lncRNA GHET1 in the cells, but decreased after its knockdown (Figure 2(f)), indicating that both MMP-9 and MMP-2 were closely related to tumor migration.