P-TEFb then associates with the super elongation complex (SEC), a scaffold formed by AF4/FMR2 Family Members 1 & 4 (AFF1/4), eleven nineteen leukaemia (ENL)/ALL1-fused gene from chromosome 9 protein (AF9) and eleven nineteen lysine-rich leukaemia protein (ELL2) that facilitates HIV transcriptional elongation [63, 64]. This evidence concerns the gene AFF1 and leukemia.