MYCN and neuroblastoma: In addition, while MYCN-amplified NB tumors have increased expression of both system Xc-components compared to MYCN wild-type tumors (SLC7A11 and SLC3A2); however, both are relatively lowly expressed in NB compared to other tumors (ref. [23] and the DepMap portal, depmap.org), which suggested to us that there may be other contributions to cysteine biosynthesis.