The mTOR inhibitor Rapamycin was evaluated in NSG xenograft models of specific subtypes of primary human B-ALL, demonstrating higher efficacy in Ph-like ALL than any other B-ALL subset, but particularly in B-ALL with altered CRLF2 and JAK/STAT signaling, in which it significantly prolonged patients’ survival [110]. Here, CRLF2 is linked to acute lymphoblastic leukemia.