Pterin-6-aldehyde, a cancer cell catabolite: Identification and application in diagnosis and treatment of human cancer (urinary metabolite/folate degradation/tissue culture)

Active folic acid degradation with the forma- tion of pterin-6-aldehyde is a previously undescribed charac- teristic of cancer cells in tissue culture. Neither normal adult epithelial and fibroblastic cells nor human amniotic cells nor mouse embryonic fibroblasts degrade folic acid to a measurable degree. Twenty-nine patients whose diagnoses were not revealed until after the test of their first morning urine for pterin-6-aldehyde was completed were studied for the presence or absence of pterin-6-aldehyde by thin-layer chromatography. Pterin-6-al- dehyde was found in the urine at about 300 nmol/ml or greater only in those 13 patients with a tissue diagnosis of cancer. When the cancer was totally resected, the pterin-6-aldehyde was no longer found in the urine postoperatively. Pterin-6-aldehyde is not found in the urine of healthy patients at this level of detec- tion unless their diets are supplemented with folic acid.