Urinary and plasma Tryptophan (Trp) and cocancerogenic Trp-metabolites of the Nicotinic-acid pathway in Bladder Cancer patients

Plasma and urinary Tryptophan (Trp), as well as urinary excretion of its metabolites, performed along both the nicotinic-acid and the serotonin pathways, have been measured in 100 bladder cancer patients, in 44 patients with non urological tumors and in 30 healthy controls by means of High Performance Liquid Chromatography (HPLC). Plasma Trp levels were significantly increased in both groups of cancer patients, while only bladder cancer patients showed high urinary values of Trp and its cocancerogenic metabolites performed along the nicotinic-acid pathway (i.e., anthranilic, 3-hydroxyanthranilic acid). In bladder cancer patients this excretion pattern did not change significantly after the surgical removal of the tumor. Our results indicated that plasma Tryptophan is significantly increased and preferentially metabolized, in bladder cancer patients, via the nicotinic-acid pathway leading to an increased excretion of metabolites which could play a role in the carcinogenic induction of bladder tumor