Neopterin as a potential modulator of tumor cell growth and proliferation

The present article proposes tumor-promoting biochemical effects of the immunologically active pteridine-compound neopterin. Based on previous findings of interactions between neopterin and the cellular redox state, two major pathways of tumor progression are presented: (1) the inhibition of nitric oxide-induced apoptotic death of tumor cells via suppression of nitric oxide synthesis in the presence of neopterin; (2) the stimulatory effects of neopterin on the production and release of angiogenic growth factors. High serum neopterin concentrations are a common finding in tumor patients and correlate well with the fatal outcome of the disease. Affection of tumor tissue growth as well as formation of metastases by neopterin may provide an explanation for these clinical observations.