CXCL8 and central nervous system cancer: In addition, qRT-PCR confirmed that co-cultured neutrophils produced more cytokines, including vascular endothelial growth factor A (VEGFa), platelet-derived growth factor β (PDGFβ), IL-1β, interleukin-6(IL-6) and interleukin-8 (IL-8), which have been reported to enhance glioma growth and progression (Fig. 4e)29–32.