Human ferritins present in the sera of nude mice transplanted with human neuroblastoma or hepatocellular carcinoma.

Fifteen nude mice were inoculated with a human neuroblastoma cell line and 14 with a human primary hepatocellular carcinoma cell line. Human ferritins were detected in the sera of the mice which developed tumors. Of 14 mice bearing human neuroblastoma, 12 had human liver-type ferritin (8 to 52 ng/ml) in their sera, and three of these also had HeLa-type ferritin (acidic ferritin) (29 to 40 ng/ml). Of 10 nude mice bearing human primary hepatocellular carcinoma, eight had human liver-type ferritin (10 to 820 ng/ml), and one of these had HeLa-type ferritin at a level of 43 ng/ml. Since the ferritins in the sera of these mice were produced by the human tumor cells, these observations support the hypothesis that the elevated ferritins often found in the serum of patients with cancer are, in part, derived from their tumors.