KMT2A and acute lymphoblastic leukemia: To determine whether a telomere length effect may account for differences in UUAGGG repeats content per transcriptome seen between MLL-r and non-MLL-r ALL or between MLL-r ALL and MLL-r AML, we assessed the mean telomere length (MTL) of each cell line by HinfI/RsaI terminal restriction fragment (TRF) analysis (Figure 3A).