Dimethylarginine Dimethylaminohydrolase 1 (DDAH1) is an essential enzyme capable of degrading asymmetric dimethylarginine, which is an endogenous inhibitor of nitric oxide synthase. Increased expression of DDAH1 and subsequent increased NO production are associated with carcinogenesis. In particular, DDAH1 is involved in the creation of a vascular network by tumor cells, vasculogenic mimicry, which is closely associated with tumor progression and poor patient prognosis. This is the reason why DDAH1 may be a potential therapeutic target for the treatment of cancer.