RT Journal Article SR Electronic T1 Cutting Edge: Codeletion of the Ras GTPase-Activating Proteins (RasGAPs) Neurofibromin 1 and p120 RasGAP in T Cells Results in the Development of T Cell Acute Lymphoblastic Leukemia JF The Journal of Immunology JO J. Immunol. FD American Association of Immunologists SP 31 OP 35 DO 10.4049/jimmunol.1402639 VO 195 IS 1 A1 Lubeck, Beth A. A1 Lapinski, Philip E. A1 Oliver, Jennifer A. A1 Ksionda, Olga A1 Parada, Luis F. A1 Zhu, Yuan A1 Maillard, Ivan A1 Chiang, Mark A1 Roose, Jeroen A1 King, Philip D. YR 2015 UL http://www.jimmunol.org/content/195/1/31.abstract AB Ras GTPase-activating proteins (RasGAPs) inhibit signal transduction initiated through the Ras small GTP-binding protein. However, which members of the RasGAP family act as negative regulators of T cell responses is not completely understood. In this study, we investigated potential roles for the RasGAPs RASA1 and neurofibromin 1 (NF1) in T cells through the generation and analysis of T cell–specific RASA1 and NF1 double-deficient mice. In contrast to mice lacking either RasGAP alone in T cells, double-deficient mice developed T cell acute lymphoblastic leukemia/lymphoma, which originated at an early point in T cell development and was dependent on activating mutations in the Notch1 gene. These findings highlight RASA1 and NF1 as cotumor suppressors in the T cell lineage.