Furthermore, transplantation of the CCR7 expressing human pediatric T-ALL cell line, CCRF-CEM, into immunocompromised Rag2−/− Il-2Rγ−/− mice increased the leukemia load and CNS involvement when compared to a human pediatric T-ALL cell line, DND41, that lacked CCR7 expression, in which no CNS infiltration was observed. This evidence concerns the gene RAG2 and acute lymphoblastic leukemia.