IL33 and neoplasm: More recently, we have demonstrated significant increased expression of IL-33 and ST2 from the colorectal precancerous (adenoma) lesion to cancerous lesion; IL-33-immunoreactivity (IR) and St2-IR are not only expressed in tumor cells, but also in surrounding stromal cells, indicating a mixt cellular source of IL-33 and ST2 in the tumor microenvironment [35].