To further investigate which factors was regulated by OR51B5 in inhibiting the proliferation and metastasis of ESCC cells, western blot assay and quantitative densitometric analysis confirmed that N-Ras isoform was significantly suppressed in OR51B5-overexpressing ESCC cells (Fig. 6H, lanes 2 and 4; Fig. 6I, right cycle and square). This evidence concerns the gene OR51B5 and esophageal squamous cell carcinoma.