Protein-arginine deiminase type-4 (PAD4) protein contributes to the formation of neutrophil extranuclear traps (NETs), which in turn lead to tumor growth and cancer immune escape that favors metastatic disease. The expression of PAD4 in certain types of cells, such as hematopoietic stem cells, makes the strategy of PAD4 inhibition risky due to adverse side effects.