IL6 and central nervous system cancer: These results suggested that in macrophages, exposure to either a hypoxic environment (+ normoxia-treated glioma supernatants) or hypoxia-treated glioma supernatants (+ normoxia) resulted lower levels of expression of M1 markers (e.g., IL-6 and TNF-α) and higher levels of M2 marker expression (e.g., IL-10 and CCL-22) than were observed in the control group (normoxia + normoxia-treated glioma supernatants) (Figure 5A-5D).