Immunohistochemical studies have revealed that both IL-33 and ST2 were widely expressed by ESCC cells,18 which leads researchers to hypothesize that elevated IL-33 expression in the tumor microenvironment might be particularly involved in the progression stage of ESCC by enhancing immunosuppression,19,67 tumor angiogenesis,20 and metastasis,19,32 but might not act as a driving force to promote the initiation of ESCC. This evidence concerns the gene IL33 and esophageal squamous cell carcinoma.