HRAS and neoplasm: The few reported successes in the creation of human tumor cells depended on the use of chemical or physical agents to achieve immortalization, the selection of rare, spontaneously arising immortalized cells, the use of an entire viral genome, or the ectopic expression of the telomerase catalytic subunit (hTERT) in combination with two oncogenes (the simian virus 40 large-T oncoprotein and an oncogenic allele of H-ras) (24).