These observations were further supported by lentiviral-mediated PAK6 knockdown in CD34+ CML cells, which led to a decrease in MDM2 as well as associated increases in p21, p27, and γH2Ax, which was reflective of what we observed in our cell line knockdown models (Figure 7B). This evidence concerns the gene MDM2 and chronic myelogenous leukemia, BCR-ABL1 positive.