Abstract: The present invention relates to murine genomic regions, identified by retroviral insertional tagging of mice as being involved in tumor development, in particular leukemia development, as well as human homologues thereof, and to the use of these genomic regions for the identification and development of anti-cancer drugs, such as small molecule inhibitors, antibodies, ribozymes, antisense molecules and RNA interference (RNAi) molecules, that are effective in reducing or eliminating the tumorigenic effects of genetic transformations in these genomic regions and/or eliminating the tumorigenic effects of expression products thereof. The invention further relates to these anti-cancer drugs and to their use as pharmaceutical reagents for the treatment of cancer, as well as to pharmaceutical compositions comprising one or more of said pharmaceutical reagents and to methods for the treatment of cancer using said pharmaceutical compositions, in particular to methods of gene therapy.