[Activity of creatine kinase and other enzymes of the carbohydrate and protein metabolism in benign and malignant tumors of man. Enzyme studies of human tumors. I]

Activities of proteinases and of a proteinase B inhibitor in tumors of the human uterus

The activities of an acid proteinase, of an alkaline proteinase, of a lysine aminopeptidase and of a proteinase B inhibitor were measured in benign and malignant tumors of the human uterus. In carcinomas of the corpus uteri the activity of the acid proteinase (cathepsin D) was increased compared to normal endometrium. This could probably be the result of cell destruction within the tumor. In leiomyomas of the uterus the activities of the alkaline proteinase, of the lysine aminopeptidase, and of the proteinase inhibitor were decreased compared to the normal myometrium. These results suggest that a decrease in the rate of degradation of myofibrillar proteins relative to the rate of protein synthesis may be responsible for the growth of myomas.

Elevation of brain-type creatine kinase in serum from patients with carcinoma

The brain isoenzyme of creatine kinase (CK BB) occurs in trace amounts in normal serum and is moderately increased in only a small number of non-oncological conditions. Although many tissues and tumors contain CK BB, we observed serum elevations only in certain carcinomas. Eleven patients with tissue-proven small cell anaplastic carcinoma (SCAC) of the lung had striking elevations of serum CK BB and no evidence of central nervous system (CNS) metastases. Significant increases were also observed in three cases of prostatic carcinoma with no apparent CNS involvement, and in one case each of adenocarcinoma and SCAC of the lung with proven CNS metastases. Three patients with SCAC of lung without distant metastases, three with SCAC of the esophagus with distant metastases but no known CNS involvement, and 17 patients with oncological conditions other than SCAC of the lung or adenocarcinoma of the prostate have failed to show elevation in serum CK BB activity. Serum CK BB may be useful as a diagnostic marker or indicator of metastases for some carcinomas.

Creatine phosphokinase in prostatic tissue

A histochemical study of creatine phosphokinase (CPK) in the rat ventral prostate revealed that the epithelial cells had a high cytoplasmic activity which was retained or even increased when the cells were atrophic as a consequence of castration. Both the fibromuscular stroma, which is prominent in the ventral prostate of castrated rats, and the secretion had a high level of activity. In human benign prostatic tissue where CPK was present in the epithelium, secretion and stroma, pronounced differences in activity could sometimes be observed between the epithelium of adjacent acini and also between cells in the same acinus. There was no obvious correlation between CPK activity and degree of epithelial hyperplasia. The activity in carcinomatous prostatic epithelial cells varied considerably between specimen from different patients but was uniform within a given specimen in contrast to the variation of epithelial CPK activity within non-carcinomatous tissue. Thus, a difference in the pattern of CPK activity was observed between malignant and non-malignant epithelial cells.