IGF2 and breast cancer: IGF-1 and IGF-2 are also expressed in the stroma surrounding cancer cells in human TNBC samples (Supplementary Fig. S2A), and gene expression analysis of Igf-1 and Igf-2 in human MDA-MB-231 TNBC cells and primary human macrophages revealed that human macrophages express high levels of Igf-1 and Igf-2, whereas there was very little expression of these ligands in the breast cancer cells (Supplementary Fig. S2B and C).