MX1 and leukemia: Principal component analysis (PCA) revealed that LK cells from control and Mx1-CreCbfb+/mDE mice, which do not develop leukemia, clustered together, and were distinctly separated from LK cells from Mx1-CreCbfb+/56M and Mx1-CreCbfb+/56M-ΔHABD mice, which do develop leukemia (Figure 4A).