Complement antagonists such as the anti-C5 monoclonal antibody eculizumab which is FDA-approved for paroxysmal nocturnal haemoglobinuria and other antagonists including pexelizumab, TP-10, MLN-2222 which are in advanced clinical development for coronary artery bypass grafting, represent opportunities for cancer therapy repurposing64. The gene discussed is C5; the disease is paroxysmal nocturnal hemoglobinuria.