In head and neck squamous cell carcinoma (HNSCC) and esophageal squamous cell carcinoma (ESCC), increased tumor cell invasion was correlated with induction of ALP and MMP9 activity by direct contact between tumor cells and hBMMSCs, and by activation of the Gremlin1-dependent TGF-β/BMP signaling pathway by hBMMSC-CM, respectively [146, 147]. This evidence concerns the gene MMP9 and esophageal squamous cell carcinoma.