Functional studies revealed that HOXD11 could enhance invasion, decompose the extracellular matrix, and epithelial mesenchymal transition-like phenotype metastasis through various downstream genes and pathways (e.g., JAM-A gene, NF-κB and FN1/MMP2/MMP9 signaling pathways) [35, 36]; however, it could also regulate the TGF-β signaling pathway to inhibit cell proliferation and cell cycle, i.e., functions like a tumor suppressor [37]. This evidence concerns the gene MMP9 and neoplasm.