PAK2 and chronic myelogenous leukemia, BCR-ABL1 positive: 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).