Since it was reported that PRAF3 inhibited melanoma metastasis by integrin aVb3 signaling [10] and integrin aVb3 could promote tumor metastasis by activating MMP-2 [19], we further analyzed the expression of integrin aV and b3 subunits in ESCC cells infected with Ad.PRAF3 (or Ad.Null) by western blot. The gene discussed is ARL6IP5; the disease is esophageal squamous cell carcinoma.