In order to understand the metabolic significance of changes in activities of enzymes involved in nucleic acid metabolism of tumor tissues in the field of orthopedic surgery, activities of ribonuclease (RNase), deoxyribonuclease (DNase), soluble 5 ´-nucleotidase and alkaline phosphatase were determined in bone tumor and soft tumor tissues of osteogenic sarcoma (OS), osteochondroma (OC), chondromatosis (CM), metastatic squamous cell carcinoma (MSCa), metastatic adenocarcinoma.(MACa) and giant cell tumor (GT) and were compared with those of normal tissues. Also measured were activities of those enzymes in serum of normal persons and patients with osteogenic tumors.
1) Activities of acid and neutral RNases in bone tumor and soft tumor tissues of osteogenic tumors studied in the present study were increased as compared with those of normal tissues, the degree of increment being greater in neutral RNase than in acid RNase. The results indicated that neutral RNase might play an important role in RNA metabolism of osteogenic
1 tumor tissues.
2) Substrate specificity for neutral RNase in bone tumor and surrounding soft tissues of OS (tibia) appeared to be different from that in normal control tissues. The results suggested that neutral RNase in the tumor tissues might be different from the normal enzymes and might be specific for the cancer.
3) While activities of acid RNase in serum of patients with osteogenic tumors studied were unchanged, activities of neutral RNase were increased. This may be due to the facts that neutral RNase activities were increased in the bone tumor and soft tumor tissues and the enzyme in-creased in the activities were leaked out of the tumor tissues into blood.
4) Activities of DNase were profoundly increased in bone tumor and soft tumor tissues of MSCa (foot and thigh), suggesting that the enzyme may play a role in carcinogenesis of MSCa through the increase in the enzyme activity.
5) Activities of soluble 5´-nucleotidase and alkaline phosphatase in some of bone tumor and soft tumor tissues and serum of patient with osteogenic sarcoma studied were changed. Activities of the serum enzyme, however, did not reflect changes in the enzyme activities of the tumor tissues.
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