We examined metformin-induced mRNA expression changes in two human ESCC cell lines...The result indicated HSPA6 as a promising biomarker. HSPA6 expression correlated with disease-free survival (DFS) of the patients with all stage ESCC (p = 0.021), especially with stage I/II ESCC (p < 0.001)...This NGS analysis detected prospective candidate genes, including HSPA6. Our results indicate that HSPA6 is a promising biomarker of the recurrence risk of stage I/II ESCC.