IL6 and central nervous system cancer: Whereas, the alternative phenotype M2 can be targeted by the signal transducer and activator of transcription 3 (STAT3), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-beta (TNF-β), and arginase production, matrix metalloproteinases (MMP)-9 and MMP-14, and promotes glioma progression [15,87,88,89].