The clinically most important ABC-transporters are the MDR1 (MultiDrug Resistance protein 1, P-glycoprotein-170) having prognostic role in acute myeloid leukemia [2], sarcomas [3,4] and gallbladder carcinoma [5]; and MRP1 (Multidrug resistant Associated/Related Protein 1), which has prognostic relevance in neuroblastoma [6], hepatocellular carcinoma [7] and in non small cell lung cancer [8]. Here, ABCB1 is linked to neuroblastoma.