It has now been found that the introduction of single stranded oligonucleotides of DNA or RNA, particularly RNA transcribed from portions of wild type prohibitin 3'UTR, into tumors leads to arrested cell proliferation. Significant reduction in the size of primary tumors has been observed following direct administration of prohibitin 3'UTR RNA. Induction of systemic immunity, as evidenced by the disappearance of metastases as well as the lack of tumor growth in rechallenged animals following prohibitin RNA therapy, has been observed. Thus, wild type RNAs transcribed from portions of a prohibitin 3'UTR, or single stranded DNAs comprised of portions of a prohibitin 3'UTR, or synthetically-made oligonucleotides of the same sequences, can be directly administered as therapeutic agents against tumors.