Furthermore, higher levels of IL-33 in ESCC tissues have also been correlated with the concomitant increased numbers of M2 macrophages: the cytokine proves to be able to promote M2 polarization via the ornithine decarboxylase (ODC) enzyme, favoring a pro-tumorigenic environment [92]. This evidence concerns the gene ODC1 and esophageal squamous cell carcinoma.