EZH2 mutations are associated with transcriptional regulation of FOXP1. (A) Venn diagram displaying the respective overlaps of downregulated genes according to EZH2 mutation status. Three genes (FOXP1, TCL1A, and RASGRP2) were found to be consistently downregulated in EZH2-mutant cases. (B) Assessment of FOXP1 messenger RNA transcript levels showed significant downregulation of FOXP1 expression in EZH2- and MEF2B-mutated cases compared with wild-type. (C) Depicted are hematoxylin and eosin (H&E; left) and FOXP1 IHC (right) of an EZH2-unmutated and EZH2-mutated case, respectively. Original magnification ×200 (H&E) and ×100 (FOXP1 IHC; insets ×400). (D) Stacked bar plot showing the distribution of percentages of positively stained tumor cells and the staining intensity. Numbers on the y-axis represent the number of cases with the respective pattern.