['Matrix metalloproteinases (MMPs) regulated by ets transcription factors facilitate carcinoma cell invasion. An ets family member, ESE-1, is expressed specifically in epithelial tissues, but its association with MMPs is obscure. In this study, we investigated whether ESE-1 regulates invasion of oral squamous cell carcinoma (SCC) via transcriptional activity of MMP-9.', 'HSC-3 and KB were used as human oral SCC lines. The expression of ESE-1 and MMP-9 was detected by in situ hybridization and immunohistochemistry. Invasion assay, gelatin zymography and Northern blotting were used to detect the invasion activity, the gelatinolytic activity and the expression of MMP-9 in the ESE-1 transfectants. Luciferase assays and mutation analysis were used for the transcriptional analysis of MMP-9 promoter region by ESE-1.', 'ESE-1 was expressed in the intermediate layer but not in the invasive area, in which MMP-9 was expressed, in the oral SCC tissues. ESE-1 suppressed invasion activity and 92 kDa gelatinolytic activity in HSC-3 as a result of transfection. ESE-1 regulates MMP-9 expression in a negative manner and the ets binding site on the MMP-9 promoter contributed to suppression by ESE-1.'] Does eSE-1 inhibit the invasion of oral squamous cell carcinoma in conjunction with MMP-9 suppression?