DNTT and Burkitt lymphoma: In addition, using this new model system for BL, we discovered that high level Myc expression in human cord blood B cells induces expression of cellular genes normally expressed at maximal levels in immature B cells, including IGLL1 (CD179B), IL7R, RAG1 and DNTT (TDT), and that in some cases this effect is mediated by Myc-induced expression of the Myb transcription factor.