IMCs in our model also secrete M2 marker proteins including YM1, arginase-1, MRC1 (soluble CD206) and legumain (Luo, 2006; Biswas & Mantovani, 2010; Murray & Wynn, 2011) (Supplementary Table S1) and promote tumour cell growth in vitro and ex vivo (Fig3). Here, MRC1 is linked to neoplasm.