We focused on the cell cycle inhibitor CDKN1A mRNA, and in a quantitative PCR validation experiment, we demonstrated that CDKN1A expression was significantly lower in ALL samples with low JQ1 EC50 values, whereas it's upstream negative regulator MYC was significantly higher in the same category of leukaemias (Figure 3a). This evidence concerns the gene CDKN1A and acute lymphoblastic leukemia.