Furthermore, we investigated the relative protein and mRNA expression levels of STK3 in various ESCC cell lines, including KYSE150, KYSE450, KYSE30, ECA109, and TE1, and compared to normal esophageal epithelium cell line HET-1A, by using Western blotting (Fig. 1e) and quantitative PCR (Fig. 1f), respectively. The gene discussed is STK3; the disease is esophageal squamous cell carcinoma.