MMP9 and thyroid cancer: Various studies showed that BTG1 overexpression suppressed proliferation, migration and invasion, and induced apoptosis and cell cycle arrest of lung, kidney, breast, esophageal, hepatocellular, nasopharyngeal, and thyroid cancers with Cyclin D1, Bcl-2, and MMP-9 hypoexpression (23–26, 29, 34, 35).