ABCG2 and neuroblastoma: These clinical data obtained in three independent cohorts of EWS patients are in conformity with a recent report on pancreatic ductal adenocarcinoma [37] and a previous observation in neuroblastoma [38], but in sharp contrast with the general idea that overexpression of ABC transporters is associated with more pronounced malignancy and drug resistance due to their capabilities to export drugs or toxins (through their canonical function of detoxification) [39].