AFF1 and leukemia: MLL chromosomal translocations with AF4 (AFF1), AF9 (MLLT3), ENL (MLLT1), AF10 (MLLT10), ELL, and AF6 (MLLT4) partner genes are found in approximately 85% of MLL-r leukemia [43], where all but AF6 encode for nuclear proteins interacting in an elongation-assisting protein (EAP) complex [44], also known as super-elongation complex or AF4, and ENL family protein complex [45,46].