Cholesterol accumulation in heterotransplanted renal cell cancer

To date there have been no in vivo studies of the known propensity of human renal cell cancer (RCC) to accumulate large amounts of cholesterol. Caki-1, a human RCC line, was grown in the cheek pouches of immunosuppressed golden Syrian hamsters. Analysis of cholesterol levels revealed 2 to 4 times as much cholesterol in the heterotransplants as in any of the host tissues. After intraperitoneal injection of tumor-bearing hamsters with 4-14C-cholesterol, the tumors accumulated less radioactivity than did hamster liver and no more radioactivity than did hamster kidney or cheek pouch. It appears that accumulation of cholesterol by human RCC is not dependent on extensive uptake of extracellular cholesterol. Instead, an intrinsic defect in the cellular regulation of cholesterol synthesis and efflux is more likely to be responsible.