BDNF and glioma: BDNF stimulates the production of Interleukin-15 (IL-15) in the brain of glioma-mice, and IL-15, in turn, stimulates natural kill (NK) cells to produce Interferon-gamma (IFN-γ) that affects the phenotype of myeloid cells, promoting the transition to an anti-tumour state (Garofalo et al., 2017).