IL13 and neoplasm: Macrophages exist in multiple states of activation with so-called M1 and M2 describing their extremes; M1 macrophages (generated through LPS/IFN-γ stimulation) are pro-inflammatory and are thought to possess anti-tumor functions; M2 macrophages (produced following Interleukin (IL)-4/IL-13 treatment) are considered anti-inflammatory and pro-tumor [14, 15].