We describe a method to inhibit cell division of hyperproliferative cells, typically cancer cells, by introducing inhibitory RNA (RNAi) into said cells to ablate mRNAs that encode polypeptides involved in cellular processes and including RNAi molecules and vectors including transcription cassettes encoding said RNAi molecules. By application of said RNAi molecules to cancers in vivo it is possible to effect a treatment whereby the cancer cells are killed or otherwise eliminated.