Tumor-associated macrophages were also shown to express Siglec-15, and the interaction between Siglec-15 on M2 macrophages and tumor-associated sialyl-Tn (sTn) antigen elevated macrophage-produced TGF-β, a known pleiotropic mediator of pro-tumor responses (31). Here, TGFB1 is linked to neoplasm.