STUDIES IN CANCER. VII. ENZYME DEFICIENCY IN HUMAN AND EXPERIMENTAL CANCER 1

Abstract

A series of human and animal neoplasms was investigated for their biochemical activity in relation to their pathological status. The chemical studies included cytochrome-oxidase system or succinoxidase activities and aerobic glycolysis. In general most neoplasms are deficient in the first 2 of these, but only frank cancers exhibit characteristic changes involving all 3 criteria. In animals developing neoplasia under the influence of a chemical carcinogenic agent or of a virus, loss of cytochrome system activity definitely precedes the histological appearance of frank malignancy and the appearance of aerobic glycolysis. Neoplastic tissue which is obviously not malignant may show striking diminution in this capacity for oxidative activity. These findings are discussed (1) as chemical criteria of neoplasia and (2) as evidence that the process of carcinogenesis involves a preliminary loss of oxidase activity.