KMT2A and leukemia: MLL-rearranged leukemias are characterized by a wide variety of fusion partner genes, with the eight most common being ALF Transcription Elongation Factor 1 AFF1 (AF4), MLLT3 Super Elongation Complex Subunit MLLT3 (AF9), MLLT1 Super Elongation Complex Subunit MLLT1 (ENL), Histone Lysine Methyltransferase DOT1L Cofactor MLLT10 (AF10), Elongation Factor For RNA Polymerase II ELL, Adherens Junction Formation Factor AFDN (AF6), Epidermal Growth Factor Receptor Pathway Substrate 15 EPS15, and partial tandem duplication PTD, which are present in over 90% of cases [10].