CCL2 and neoplasm: Notably, existing research has indicated that untreated neuroblastic tumors tissues are enriched with tumor-associated macrophages (TAM), tumor-associated fibroblasts (CAF), and their precursor mesenchymal stromal cells (MSC), which interact with neuroblastic tumors cells to induce the production of cytokines such as transforming growth factor-β1 (TGF-β1), monocyte chemoattractant protein-1 (MCP-1), interleukin-6 (IL-6), and interleukin-8 (IL-8) (25–27).