The plasma copper level (PCL) and plasma zinc level (PZL) were determined in 126 patients: 54 had carcinomas of which 40 were carcinomas of the digestive organs, 37 had benign lesions, and 35 were without disease. The PCL increased and the PZL decreased significantly in the group with carcinoma of the digestive organs. The CdZn ratio was not only significantly higher than in the normal group, but also was high in cases with advanced carcinoma especially when liver metastasis was present. Therefore, the Cu/Zn ratio may be valuable in estimating the extent of the carcinoma as well as in determining the prognosis of the cancer patients.Cancer 42:626-631, 1978.HE LEVELS of copper and zinc in the T plasma or serum of patients with various diseases have been studied for some time and have been reported frequently. It has been pointed out that the plasma copper level (PCL) increased and the zinc level (PZL) decreased in a variety of diseases. But these changes varied depending on the stage of the disease. It was also thought that the ratio of PCL to PZL (Cu/Zn ratio) demonstrated more remarkable changes because PCL increased and PZL decreased in these diseases. This study concerns the levels of PCL and PZL in patients with malignant tumors, particularly carcinoma of the digestive organs, and the clinical evaluation of the Cu/Zn ratio. Table 1 identifies the 124 cases studied. There were 24 cases of primary carcinoma of the stomach, and 5 with recurrent disease. Eleven patients had carcinoma of other digestive organs, and 14 had cancers of other organs. There were 37 cases with benign disease (peptic ulcer, cholelithiasis, etc.), and 35 were normal subjects free of disease. Patients taking oral contraceptives were eliminated from the study. All but 5 of the carcinomas were primary in the digestive organs; the 5 exceptions were recurrent cancers of the stomach. Liver metastases were present in 8 cases, 5 found at the time of operation, 2 at autopsy, and one diagnosed clinically.The liver function was studied by routine laboratory tests such as total protein, serum bilirubin, SGOT, alkaline phosphatase, LDH, and 7-globulin. Out of the 35 cases with primary carcinoma of the digestive organs, 24 were found to have no disturbance of liver function or liver metastasis. Out of all the carcinomas, 36 had no liver disorders. There were 10 cases with disturbed liver function: 4 with cholelithiasis (elevated alkaline phosphatase in 4 cases, and elevated total bilirubin level of serum in 2 cases), 5 with liver cirrhosis (esophageal varices and elevated y-globulin in all cases), and one case with acute serum hepatitis (elevated serum transaminase) after partial gastrectomy for peptic ulcer. No malignant tumors were found in this group, and the a-fetoprotein was also negative.Blood was obtained when the patients were fasting. The glassware was rinsed with a dilution of H N 0 3 and doubly distilled water. New standards were prepared always on the day of each analysis. Plasma was isolated from the heparinized blood and stored frozen. A...