New applications of urinary nucleoside markers.

In order to extend the usefulness of the quantitation of urinary nucleoside markers, studies were undertaken to explore the adaptability of such determinations for early detection in cancer-prone populations such as asbestos workers. Another study was aimed at exploring the usefulness of therapy in individual patients. During these studies, two heretofore unknown phenomena serendipitously emerged which expand the versatility of the marker determinations: (a) radiation damage in animals and humans causes an excretion of urinary BAIB which from preliminary studies appears to be proportional to the irradiation burden, and (b) lead poisoning in the human also produces BAIB excretion. Some of the practical uses of these determinations are self-evident. Among 13 asbestos workers without clinical symptoms, eight were found to have significant elevations of the marker levels. Nine asbestos workers with diagnosed mesothelioma all excreted two or more markers at high levels. Some of the psi levels were the highest seen. Currently the diagnosis of mesothelioma is difficult and painful, requiring a rib resection; however, an asbestos worker with such elevations--provided small cell carcinoma of the lung is ruled out--can be seriously suspected of having mesothelioma. In a study of the usefulness of the markers in following therapy of trophoblastic disease, these markers were determined in women with incipient invasive hydatidiform mole. After curettage, the nucleoside markers indicated absence of residual disease but the usual marker, HCG, was still markedly elevated. The women were followed up for 2 years and were found to remain symptom-free. Therefore the source of the nucleoside markers is cleared more rapidly than that of HCG.