SIGLEC1 and neoplasm: Examples of non-M1/M2 cells are: CD169+ macrophages, detected in bone marrow, lymph node, liver, and spleen, and mainly involved in erythropoiesis and immune regulation; macrophages expressing TCRαβ or TCRγδ identified in inflammatory and infectious diseases; a novel subtype of tumor-associated macrophages characterized by an M2-like immunosuppressive gene profile and expressing a novel receptor “macrophage receptor with collagenous structure” (MARCO), detected in mouse tumor models of mammary carcinoma, colon cancer and B16 melanoma (128).