Previous data have shown that RSV decrease the expression of Mcl-1 in T-cell acute lymphoblasticleukemia cells [42], up-regulated Bax in Burkitt’s lymphoma cells [34], activated caspase-9 in acute lymphoblastic leukemia cells [36] and induced the cleavage of caspase-3 in human T-cell leukemia virus type 1 (HTLV-1) [43]. This evidence concerns the gene CASP9 and acute lymphoblastic leukemia.