Changes in blood magnesium and calcium concentrations in patients with stomach cancer.

Blood magnesium (Mg) and calcium (Ca) concentrations were determined in patients with stomach cancer and in normal subjects. The patients were classified into four stages of malignancy and three metastatic categories. High Mg levels were found in plasma and whole blood of patients in the early stages of stomach cancer, while low Ca levels were found in blood plasma in most stages and in all metastatic groups. By contrast, high Ca levels were observed in whole blood in the later malignancy stages and in two of the metastatic categories. The calcium level in blood plasma does not therefore seem to depend on the stage of malignancy and metastasis, while the calcium level in whole blood and the Mg level in blood plasma and whole blood do appear to depend on the stage of malignancy or metastasis.