KLF4 and myeloid leukemia: Furthermore, we observed the downregulation of Mxd family genes, i.e., Mxd1, Mxd2/Mxi1, and Mxd4. Interestingly, Krüppel-like factor 4 (KLF4) has been identified as an upstream transcriptional regulator of Mxd1 and Myc in myeloid leukemias [41].