Abstract Malignant rhabdoid tumors (MRTs) are rare, aggressive cancers occuring in young children primarily through inactivation of the SNF5 tumor suppressor gene. Espetially, rhabdoid tumor arised from brain is usually called AT/RT. We and others have demonstrated that mice heterozygous for a Snf5 null allele develop MRTs with partial penetrance. We have also shown that Snf5+/− mice that lacked expression of the pRb family, due to TgT121 transgene expression, developed MRTs with increased penetrance and decreased latency. In this current study, we observed that the genetic background altered MRT development in Snf5+/− and TgT121;Snf5+/− mice, resulting in increased latency and the appearance of significant frequency of brain tumors. We also report the establishment of the first mouse MRT cell lines that recapitulate many features of their human counterparts including lack of genomic instability and expression of smooth muscle and neuronal differentiation markers. The cell lines also form aggressive tumors upon inoculation into immunocompromised mice that resemble the tumors of origin. Our studies provide further insight into the genetic influences on MRT development as well as provide valuable new cell culture and genetically engineered mouse models for the study of AT/RT etiology. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 1359. doi:1538-7445.AM2012-1359