DPP4 and neuroblastoma: DPP4 (dipeptidyl-peptidase 4, also called CD26) was up-regulated in artery smooth muscle cells exposed to 1,25(OH)2D3[46] and its overexpression in distinct cell types (melanocytes, non-small cell lung, prostate and neuroblastoma cells) triggered anti-tumorigenic effects including cell growth arrest, inhibition of cell migration and increased apoptosis [47].