CD33 and neoplasm: A similar result was obtained when a macrophage signature comprising a subset of eight widely used markers (CD14, CD105, CD11b, CD68, CD93, CD33, IL-4R and CD163) for the mononuclear phagocyte system [37] was used to identify tumours highly infiltrated by macrophages (Fig. 1e and f and Additional file 5: Table S3).