Furthermore, immunohistochemistry revealed that AE1 was overexpressed in ESCC tissue, and that diffuse AE1 expression was a valid poor prognostic factor for advanced esophageal cancer, suggesting that the role of AE1 in the regulation of tumor behavior is opposite to that of AE2 [11]. The gene discussed is SLC4A1; the disease is esophageal squamous cell carcinoma.