Consistent with this result, SIGLEC15 expression in 698 glioma tissues samples was positively correlated with the gene expression of M2-like macrophage markers, including C-type mannose receptor 1 (MRC1, also known as CD206) and Transforming growth factor 1 (TGFB1) (Figure 1C). Here, TGFB1 is linked to glioma.