The formation of an immunosuppressive milieu favors the initiation and progression of cancers, and studies have confirmed that the shift of macrophage polarization from Th1 to Th2 phenotypes is implicated in the establishment of immunosuppression in esophageal cancer.66 Mai et al.67 have found that increased IL-33 contributes to enhanced infiltration of M2-type macrophages into ESCC tissues by activating ornithine decarboxylase (a key enzyme that catalyzes the synthesis of polyamines). The gene discussed is IL33; the disease is esophageal cancer.