Furthermore, qRT-PCR results showed that RCC-derived exosomes increased the mRNA expression levels of markers of M2-like macrophages, including IL-1RA, CD163, CD206 and CCL18 (Figure 2B), while there was no significant effect on the mRNA expression levels of markers of M1-like macrophages, including TNF-α, IL-1β and MCP-1. Here, CCL18 is linked to renal cell carcinoma.