FLASH was originally identified as a pro-apoptotic protein involved in Fas-mediated caspase-8 activation.22 In acute lymphoblastic leukemia patients, loss of FLASH expression was correlated with poor treatment response and relapse.28, 29 However, an antiapoptotic role for FLASH has been described in studies showing that FLASH can suppress apoptosis in both Fas-dependent and -independent manners.20, 25 These studies performed in fibrosarcoma cells and colorectal carcinoma cells suggest that FLASH can promote or inhibit apoptosis depending on the context and cell type involved. This evidence concerns the gene CASP8AP2 and acute lymphoblastic leukemia.