The influence of choline on the transplantation of a lymphoid tumor (RPL-12) into chicks.

The phospholipid content of tumor tissue has been found to be relatively high (1, 6, 9). Haven (4) presented evidence that the choline-containing phospholipid, lecithin, had a higher rate of turn over than the noncholine-containing cephalin. This finding has led to a number of investigations on the effect of dietary choline on tumor develop ment. Thus, Copeland and Salmon (3) reported that a dietary deficiency of choline resulted in in creased tumor formation in rats. Later, these ob servations were extended to chickens (8). However, it has been shown by Jacobi and Baumann (5) that a deficiency of choline or the addi tion of 0.3 per cent choline to a stock diet was without effect on the development of established tumors in mice. In addition, Cook and Schoental (2) reported that adding choline to the drinking water at a level of 1 per cent had no influence on the development of tumors in rats injected with 1,2,5,6-dibenzanthracene. Chickens are naturally susceptible to many forms of tumor, one of the most common types be ing lymphoid in nature. A strain of transplantable lymphoid tumor, RPL-12, has been maintained for many years in various laboratories. The purpose of the work presented in this report was to investi gate the influence of high dietary levels of choline and other lipotropic agents on the transplantation of the RPL-12 tumor into chicks.