Endogenous NPY-driven cell death in Ewing sarcoma family tumors (ESFT) can be blocked by DPPs, including DPP8/9, which also indicates that NPY can serve as an in vivo substrate of DPP8/9 (Lu et al., 2011). The gene discussed is NPY; the disease is Ewing sarcoma/peripheral primitive neuroectodermal tumor.