Arginine: Challenges and opportunities of this two-faced molecule in cancer therapy.

Numerous antitumor therapies have been developed based on the differences in cells' metabolisms. Regarding the important role of arginine (Arg) in the regulation of multiple metabolic and signaling pathways, its deprivation has been proposed as a good strategy for tumor regression in tumors with defected Arg metabolic enzymes like argininosuccinate synthase 1 (ASS1). However, modulatory effect of Arg on various cancers is also a controversial issue. Therefore, this review article intends to address some of the challenges faced by Arg deprivation method as well as Arg administration for cancer therapy.