MMP9 and esophageal squamous cell carcinoma: Since the mass spectrometry results showed that MMP2 and MMP9 were absent in SRGN Exo and Con Exo (Table S3), it is possible that decreased secretion of non-exosome-associated matrix-degrading MMPs from SRGN-overexpressing ESCC cells had contributed to the strong suppressive effects of DMA and RAB27A-knockdown on ESCC cell invasion observed in Figure 1.