ARG1 and cancer: Because the addition of human neutrophil sonicates could be considered somewhat artificial as some of the antitumor molecules present in the sonicate might not be released by neutrophils normally, we decided next to investigate the ability of different stimuli to induce secretion of arginase-1, and how this secreted arginase-1 present in conditioned medium of stimulated human neutrophils could affect cancer cell viability.