Previous studies have found that high expression of MMP1 can lead to tumor migration, invasion, and angiogenesis through various mechanisms, including the inhibition of breast cancer metastasis by downregulation of MMP1 via bone morphogenetic protein 6 (BMP-6) and the promotion of glioma cell invasion by MMP1 through the mitogen-activated protein kinase (MAPK) pathway 24-25. Here, BMP6 is linked to glioma.