The Chemistry of Cysticercus Fasciolaris

The sarcomas arising in rat livers at the surface of the cysts surrounding the tapeworm larvae, Cysticercus fasciolaris (Taeniu taeniaformis), have been extensively studied by Curtis, Dunning, and Bullock, (1). Recently in this laboratory, as part of a cooperative investigation sponsored by The International Cancer Research Foundation, a chemical investigation of the extractable components of the larvae was undertaken by Anderson and coworkers (2, 3). The opportunity has arisen in continuation of this project to examine the tumors caused by the parasite. As in the case of the larvae a large amount of carefully prepared tumor tissue was supplied by Dr. Dunning and Dr. Curtis. Although the lipids of malignant mammalian. neoplasia have been the subject of numerous investigations, they have not yet’ been subjected to a detailed chemical analysis. From the available evidence they appear in superficial character to resemble the lipids of normal tissues, although elevated levels of cholesterol esters (4) and of higher unsaturated acids determined as the polybromides (5) have been reported. Interest in tumor lipids resides in the possibilities for structural apd metabolic peculiarities, and in the numerous reports of tumor-inducing properties in the lipid extracts of tissues from various sources. Samples of the fractions obtained in the present work have been reserved for biological study. The fraction of the Gysticercus rat tumors designated acetone-soluble fat was completely soluble in cold ether and acetone and constituted 3.93 per cent of the dry weight of the tissue. Its composition and properties are summarized in Table I. Expressed as per cent of the dry weight of the tumor tissue, the amounts of fat and unsaponifiable material fall within the rather wide limits observed in normal organ tissues. In accordance with previous reports the iodine number of the fatty acids was high but the cholesterol distribution was not unusual. About 30 per cent of the fatty acids was free. The remaining acids were combined as simple glycerides. There was also present a small amount of phosphatide which was not removed during the purification.