HRS cells secrete cytokines, chemokines, and other immunomodulatory factors, such as IL-10, CCL17, galectin-1, and indoleamine 2,3-dioxygenase (IDO) that both recruit Th2 and regulatory FOXP3+ CD4+ T cells (Treg), favoring the differentiation of tumor-infiltrating T cells into regulatory and Th2 cells. The gene discussed is CD4; the disease is neoplasm.