Restoration of hydroxyindole -methyltransferase levels in human cancer cells induces a tryptophan-metabolic switch and attenuates cancer progression.

5-Methoxytryptophan (5-MTP) is a tryptophan metabolite with recently discovered anti-inflammatory and tumor-suppressing activities. Its synthesis is catalyzed by a hydroxyindole -methyltransferase (HIOMT)-like enzyme. However, the exact identity of this HIOMT in human cells remains unclear.