CHI3L1 and neoplasm: Moreover, based on the staining location on primary tumor sections, CHI3L1 and CHI3L3 were almost exclusively present at cellular necrosis sites (Additional file 7: Fig. S5A,B), which were highly populated with Ly6G+ TANs, albeit with a much lower abundance in 66cl4 compared to 4T1 primary tumors (Additional file 7: Fig. S5C).