IL4 and neoplasm: Apoptotic cell clearance via efferocytosis polarizes tumor-associated macrophages (TAM) to adopt pro-tumor ‘M2’ wound-healing phenotypes which, by secreting cytokines such as IL-4, IL-10, IL-13 and TGF-β1, further educate Th0 or Th1 CD4 T cells towards a Th2 phenotype [41].