Embodiments are directed to: (i) neutrophil secreted factors that have the capacity to kill a broad range of cancer cells without affecting the viability of non-cancer cells. Two neutrophil killing factors have been identified by the inventors: (1) eosinophil cationic protein (ECP) and (2) neutrophil elastase (ELANE); or (ii) therapeutic compositions that include CD95 degrading polypeptide components and methods of treating cancer with the same.