The metabolic profiling indicated that ESCC cells expressing CLK4‐M307Q exhibited higher GSH, oxidative PPP flux, NADPH/NADP+ ratio, ribulose‐5‐phosphate (Ru‐5‐P), the biosynthesis of RNA and DNA, and longer mitochondria, but less lipid peroxidation than the cells expressing CLK4‐M307T (Figure 11Ei‐v,F,G). The gene discussed is CLK4; the disease is esophageal squamous cell carcinoma.