In contrast, M2 macrophages, which are stimulated by IL-4 and IL-13 (produced by T-helper 2 cells), play a critical role in tumor initiation, proliferation, metastasis, and immune evasion, and express anti-inflammatory elements, such as IL-10 and transforming growth factor (TGF)-β (3, 4). This evidence concerns the gene IL13 and neoplasm.