Treatment with propargylglycine (PAG) [16], a pharmacological inhibitor of the key enzyme in the transsulfuration pathway that catalyzes the hydrolysis of cystathionine into cysteine, cystathionine γ-lyase (CSE), was sufficient to sensitize two MYCN-amplified NB cell lines to system Xc-inhibition (Fig. 2D). Here, MYCN is linked to neuroblastoma.