[Enzymes of anabolic and catabolic nucleic acid pathways in human hepatomas, in liver of healthy persons, and in liver of patients with cancer of gastrointestinal tract].

: The activities of enzymes catalyzing the formation of nucleic acid precursors, nucleoside kinases, as well as of those involved in the degradation of nucleic acids, were studied in nuclei of the liver of healthy persons, human hepatomas and the liver of patients with cancer of gastrointestinal tract. The activities of thymydine kinase and uridine kinase in the human hepatoma nuclear sap were found to increase 40- to 50-fold and 120- to 150-fold, respectively, as compared to those in normal human liver. The activities of DNase and RNase in the fraction of chromatin protein of human hepatomas, on the contrary, decreased almost to zero. As to the liver of patients with cancer of gastrointestinal tract, drastic alterations in the activities of nucleoside kinases and nucleases in the direction characteristic of tumors themselves were observed. This phenomenon is regarded as a manifestation of the systemic effects of the tumor on the host.