To determine the role of VEGF family members and MMP-9 in ESCC invasion, we used a GEO microarray dataset (GSE21293), found that MMP-9 (log FC = 1.82, P < 0.05) and VEGF-C mRNA (log FC = 1.27, P < 0.05) expression were significantly up-regulated in invading ESCC cells relative to the matched non-invading ESCC cells, while there was no significant up-regulation of VEGF-A mRNA and VEGF-B mRNA in invading ESCC cells (Figs. 1M–1P). This evidence concerns the gene MMP9 and esophageal squamous cell carcinoma.