It has been shown that IL-4, which is secreted from tumour cells and T lymphocytes46, as well as colony stimulating factor 1 (CSF-1) and granulocyte-macrophage colony-stimulating factor (GM-CSF), which are secreted from tumour cells47,48, take part in pro-tumoural differentiation of macrophages. This evidence concerns the gene IL4 and neoplasm.