TCF3 and acute lymphoblastic leukemia: Importantly, this finding of a highly indicative value of functional BCL-2 dependence for in vivo VEN sensitivity was confirmed in an independent set of preclinically treated primograft samples and extended to T-ALL and TCF3/HLF rearranged ALL, a rare subgroup associated with early relapse and dismal outcome35, for which in vitro and preclinical in vivo response to VEN had recently been reported32.