These findings are consistent with previous reports showing elevated serum IL-12p40 in osteosarcoma42, IL-8 in mammary tumor and osteosarcoma42–44, and MCP-1 in lymphoma, histiocytic sarcoma, urothelial carcinoma, and malignant melanoma45–49 compared to healthy dogs. Here, CCL2 is linked to histiocytic sarcoma.