The process of epithelial-to-mesenchymal transition (EMT) involves the acquisition of high-invasiveness by tumor. Snail represses target genes and induces EMT. In this study, we defined the signatures of gene expressions by cDNA microarray analyses in both human squamous cell carcinoma (SCC) cell lines with spontaneous EMT and with Snail-induced EMT, which exhibited high-invasive behavior in vitro. Of the 17,000 cDNA probes, 61 genes were found differentially expressed with >2- or <0.5-fold ratio and shared among the EMT phenotype cell lines, indicating candidates for invasion-associated genes regulated by Snail. Category analysis showed that these genes were mainly classified as development/differentiation, metabolism, apoptosis, angiogenesis and cell adhesion. These data illustrated that Snail regulates various molecular pathways for the establishment of EMT and the acquisition of high-invasiveness in SCC cells, yielding insight into the progression of SCC.