Western blot analysis showed that folic acid could significantly decrease the protein expression level of RPS15 in KYSE150 and KYSE510 cells (high expression of RPS15) (Fig. 7i) or in the RPS15-overexpressing ESCC cells (Fig. 7j), but weak in KYSE30 and KYSE450 cells (low expression of RPS15) (Supplementary Fig. S6c, d). The gene discussed is RPS15; the disease is esophageal squamous cell carcinoma.