HIF1A and esophageal squamous cell carcinoma: In non‐neoplastic esophageal tissues, the expression of hypoxia markers such as HIF‐1α, CA9, and GLUT1 is rare,20, 21, 22 but in ESCC, this expression increases as it invades deeper, and the high expression of hypoxia markers is associated with a poor prognosis.10, 12, 13, 14, 15, 16, 17