A diagnostic test for detecting malignancies has been reported by Rao and associates. This test has been extended by Trehan and associates as an index of disease status in acute myeloblastic leukemic patients on antileukemic drugs. The authors were able to demonstrate that by using the described assay various pteridines are measured and not exclusively 6-hydroxymethylpterin as reported by the above-mentioned authors. Furthermore, the urinary component which correlates to the status of malignant disease has to be interpreted as being neopterin. This conclusion can be drawn from previous studies conducted by the authors' laboratory.
Cuncer 53:1634-1636, 1984.
ECENTLY, studies by Rao and associates' and Trehan R and associates' concerning 6-hydroxymethylpterin levels on patients suffering from cancer appeared in this journal. Since our investigations of similar problems lead to an interpretation that is in contrast to the interpretation of these authors, it seems necessary to clarify the discrepancies.
The method described by Rao and associates involves adsorption of urinary samples on charcoal, subsequent Some species are characterized. The clinical results of both studies'.' correlate with ours5 when subjected to an altered interpretation. The difference between healthy subjects and cancer patients reported by the authors'.' originates because neopterin levels are quantitated together with other pterin levels in their assay.