HISTOCHEMICAL AND IMMUNOHISTOCHEMICAL SIMILARITIES BETWEEN HEPATIC-TUMORS IN 2 CHIMPANZEES AND MAN

A well-differentiated trabecular hepatocellular carcinoma (HCC) and a well-differentiated tumor resembling HCC from each of two chimpanzees were found to have histochemical and immunohistochemical staining char acteristics similar to those in human HCCs. Transforming growth factor alpha was overexpressed in both tumors. Oval cells, thought to be liv er stem cell progeny with a possible role in hepatocarcinogenesis, wer e observed among nontumorous hepatocytes, particularly near the tumors . Hepatic tumors are rare in chimpanzees but their similarities to hum an HCC provides a useful research model.