PECAM1 and neuroblastoma: Consistently, stable transfection of ecircCUX1 or sh-ecircCUX1 #2 into NB cells resulted in a significant increase or decrease of growth, tumor weight, long-chain fatty acid levels, complex I activity, NAD+/NADH ratio, ATP production, Ki-67 proliferation index, and CD31-positive microvessels of subcutaneous xenografts in athymic nude mice (Additional file 1: Fig. S4e, S5a, S5b).