ABCB6 and neuroblastoma: Recent in vitro and in vivo studies have shown that most neural/neural crest-derived CSCs, including brain tumor stem cells (BTSCs), glioma stem cells (GSCs), medulloblastoma (MB) as well as neuroblastoma (NB) and melanoma stem cells, are resistant to standard antitumor treatments, i.e., chemotherapy and radiotherapy, mainly due to high expression of anti-apoptotic genes, ATP binding cassette transporter (ABC) family multidrug resistance transporters, and by rapid activation of DNA damage response pathways.