UBQLN4 and esophageal squamous cell carcinoma: The Cancer Genome Atlas database analysis revealed that UBQLN4 was highly expressed (mRNA z‐score ≥ 1.5) in about 24% (23 of 95) and decreased in only 2% (mRNA z‐score ≤ 1.5) of ESCC patients (Fig. 4A).