Neutrophils in cancer. Neutrophils show both anti-tumoral (green lines) and pro-tumoral (red lines) properties that affect tumor progression in opposite ways. Identified pro-tumoral and anti-tumoral neutrophil subsets are highlighted in the respective colored boxes. TRAIL, TNF-related apoptosis-inducing ligand; VEGF, vascular endothelial growth factor; NE, neutrophil elastase.