EGF and neuroblastoma: Consistent with these data, no effect on sphingosine 1-phosphate-dependent ERK1/2 phosphorylation was detected in human umbilical vein endothelial cells upon downregulation of PI3KC2β using transient transfection of specific siRNA40 or in EGF-mediated ERK1/2 phosphorylation in SK-N-AS and IMR-5 neuroblastoma cell lines stably infected with shRNAs targeting PI3KC2β34.