To evaluate possible protective effects of MSC on CXCR4 function in neuroblastoma cells, CXCR4 immunoprecipitated from the SK-N-SH cell line, which were either serum-starved or pre-treated for 10 hrs with mRPMI, were subjected to western blot analysis for ubiquitin. The gene discussed is CXCR4; the disease is neuroblastoma.