Baseline proteomic differences between patients with BTK-WT CLL and those with BTK-mutated CLL. An RPPA assay was used for protein analyses as described in the “Patients and methods” section. Analysis of differential protein expression was performed using unpaired, 2-tailed t tests. No proteins were significantly differentially expressed after adjusting for multiple testing. (A) A PCA plot of the baseline RPPA data by BTK mutation status (BTK-WT, n = 7; BTK-mutated, n = 11). (B) Heat map of the top 20 differentially expressed proteins by log fold change. Numbers on the x-axis correspond to the patient numbers in supplemental Table 1. (C) Heat map of the top 20 differentially expressed proteins by P value. Numbers on the x-axis correspond to the patient numbers in supplemental Table 1. (D) Box plots comparing the expression of the top 10 overexpressed proteins (by P value) in the BTK-mutated and BTK-WT groups at baseline. (E) Box plots comparing the expression of the top 10 downregulated proteins (by P value) in the BTK-mutated and BTK-WT groups at baseline.