ESCC patients with high FGFR1 expression and those with low FGFR1 expression were comparable in the demographic and baseline variables except that the percentage of heavy drinkers was significantly higher in patients with high FGFR1 expression than those with low FGFR1 expression (79.0% vs 43.2%, P<0.001) (Supplementary Table 1, Supplementary Figure 2). This evidence concerns the gene FGFR1 and esophageal squamous cell carcinoma.