The human QSOX2 gene, located on chromosome 9q34.3, shares high homology with QSOX1, consists of 12 exons, and encodes a 698‐amino acid protein.[29] However, gene expression analyses using TCGA and GEO datasets revealed an inverse expression pattern between QSOX1 and QSOX2 in ESCC. The gene discussed is QSOX1; the disease is esophageal squamous cell carcinoma.