MYCN and neuroblastoma: Glutamine deprivation or downregulation of SLC1A5 induced apoptosis in MYCN-amplified NB cells and prevented tumor formation in a xenograft model.90,91 Notably, the rate-limiting enzyme of glutaminolysis, glutaminase (GLS), converting glutamine into glutamate, is directly regulated by MYCN92 and, unexpectedly, we found that MYCN-amplified NB cells synthesized glutamine de novo thus contributing to aggressiveness of these cells.80 Glutamate can further be included in the TCA cycle to obtain energy.