RAG2 and acute lymphoblastic leukemia: Langenau et al. used a Cre-inducible model (Langenau et al., 2005a) and Gutierrez et al. established conditional tamoxifen-inducible rag2:Myc-ER fish, which allowed improved analyses and assessed direct causality between Myc oncogene expression and T-ALL (Gutierrez et al., 2011).