MMP9 and central nervous system cancer: Another lncRNA metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) inhibits cell proliferation and invasion through the downregulation of extracellular signal-regulated kinase (ERK), matrix metalloproteinase 2 (MMP2) and MMP9 in U87 and U251 glioma cells and glioma nude mice models [52].