Most strikingly (and in clear contrast to neuroblastoma cell lines with acquired resistance to other anti-cancer agents that are ABCB1 substrates), ABCB1 expression is an exclusive resistance mechanism in UKF-NB-3rSNS-032300nM cells and a predominant resistance mechanism in SHEPrSNS-0322000nM cells. The gene discussed is ABCB1; the disease is cancer.