IL33 and cancer: Animal studies show that knockdown of IL-33 can remarkably decrease the development of human ESCC xenografts in BALB/c nude mice.32 Moreover, evidence obtained from various types of cancers suggests that the promoting effect of IL-33 on cancers is through the activation of tumor stromal cells.62, , –65 In our studies, we can demonstrate that both IL-33 and ST2 are widely expressed in ESCC stromal cells and microvascular ECs,18,20 suggesting a participating effect of IL-33 in the modulation of tumor stroma and angiogenesis in the ESCC microenvironment.