BTK and mantle cell lymphoma: Although the central role of BTK in B-cell receptor (BCR)-driven cell signaling is well established [3, 4, 18–21], our results demonstrate a novel and critical role of BTK in cell metabolism, given that BTK inhibition affects key metabolic pathways, including pyrimidine and purine synthesis, the TCA cycle, glycolysis, and pyruvate and alanine metabolism, in MCL cells (Fig. 2a).