Increased mutational burden in STAT3-mutated patients. (A) Boxplot of nonsilent mutational burden comparing STAT3 WT against mutant patients. P value from Wilcoxon t test. (B) Plot of the mutational burden against age for WT and mutant STAT3 patients with linear regression and colored annotation representing STAT3 mutation status. (C) Plot of mutation burden against CD3⁺ CD57⁺ fraction for T-LGL patients with linear regression and colored annotation representing STAT3 mutation status. (D) Top recurrent somatic mutations observed in STAT-mutated and WT groups. The left oncoplot shows patients with STAT3 or STAT5B mutations (n = 56), and the right oncoplot shows STAT WT (n = 49) patients. The top annotation indicates the LGL subtype. Patients with mutations in the chromatin-modifying enzyme gene list (supplemental Table 9) are annotated in the second row in gray. Three chromatin-modifying genes are highlighted in green font. The 10 genes that are most frequently mutated in WT patients are shown in the top half, followed by the 10 genes most frequently mutated in STAT3- and STAT5B-mutated patients in the bottom half. Annotation of “Alterations” indicates the type of mutation affecting the gene. SBS1 signature explains the degree of intensity of the COSMIC SBS1 signature present for each patient.