Pteridines in the assessment of neoplasia

Biological processes which might explain the association of pteridine excretion with proliferation are still unknown. Difficulties in the analysis and the determination of naturally occurring pteridines are described. The best quantitative estimations were achieved when measurement of non-reduced forms was attempted. The performance characteristics of such a method for neopterin by high performance liquid chromatography on reversed phase are given. Enhanced proliferation and dedifferentiation in cell cultures and organisms is paralleled by excretion of unconjugated pteridines into the medium or urine. Urinary neopterin in healthy subjects and in patients with benign diseases was only significantly raised in patients with viral diseases. However, an elevation of urinary neopterin occurred in a wide variety of malignant diseases. In haematologic neoplasias correlations of neopterin values to clinical features, to tumour staging, and to laboratory data were apparent. The clinical utility of neopterin measurement was also demonstrated in patients with gynaecologic tumors, particularly in patients with ovarian carcinoma. In both homogeneous patient groups the neopterin assay may provide an additional aid for prognosis and for monitoring therapy. Comparison of the neopterin assay with already established tumor marker substances at least revealed no inferiority in sensitivity. The present results justify extensive investigations in order to evaluate further the clinical applicability of the neopterin assay.