KMT2A-r AML has significantly lower levels of H3K79me2. (A) Western blot analysis for H3K79me2 in a cohort of AML patient samples from the University of Pennsylvania (A), the University of Colorado (B), and the Cancer Genome Atlas (C). See supplemental Table 1 for additional details about all patient samples. (D) Quantification of H3K79me2 levels in all patients’ western blots compared with total H3 or total H4 (Figures 1A, 6G-H). *P < .01, **P < .001; Student t test. (E) H3K79me2 immunohistochemistry of representative patient samples with and without a KMT2A-r. (F) Quantification of H3K79me2 immunohistochemistry staining. Four to 6 individual areas were analyzed for each slide. Average intensity of H3K79me2 over all areas is shown for each patient. KMT2A-r samples (n = 2), non–KMT2A-r samples (n = 3). *P < .05; Student t test.