The article reports on the consensus sequence for exons 1 and 2 of H-ras in prosimians, particularly captive lemurs and lorises, along with the evaluation of samples of nonneoplastic liver and hepatocellular carcinomas (HCC) for mutations in these exons. A background of the study is provided including the function of the ras family of proto-oncogenes. Procedures involved in the study are discussed such as complete postmortem examinations on animals, deoxyribonucleic acid (DNA) isolation, and polymerase chain reaction (PCR).