(Cancer Cell 35, 782–797.e1–e8; May 13, 2019) In the originally published version of this article, the legend of Figures 3B–3E, “(B–E) Mass spectrometry analysis in DIPG-XIII for total (B), H3K27ac (C), K27M (D), and H3K27me3 (E) peptides among total H3,” misstated the labels of (C) and (D), which were inverted. The legend should read “(B–E) Mass spectrometry analysis in DIPG-XIII for total H3.3 (B), K27M (C), H3K27ac (D), and H3K27me3 (E) peptides among total H3, plot of mean of n = 3 or 4 technical replicates. Solid horizontal lines indicate the mean.” In the Supplemental Information, the labels of the pie chart in Figure S2H were incorrectly duplicated. In the originally published version, both gray and orange sections were labeled as “sites gained upon KO.” The gray section of Figure S2H has been correctly labeled to “sites retained upon KO”. The text and conclusions of the paper are not affected by these corrections. The authors apologize for any inconvenience the errors may have caused.