The expression of many of the genes such as TNFα, IL-6, IL-10, and MCP-1 exhibited similar kinetics between contact and non-contact co-cultures (Figure 3), but the levels of induction were much lower in non-contact co-culture, suggesting that soluble factors are sufficient for the induction of these genes and direct interaction between macrophages and NPC cells augments their expression. Here, CCL2 is linked to nasopharyngeal carcinoma.