IR DLBCL cells show enhanced PI3K/AKT/mTOR signaling. (A) Western blot analyses of BTK expression in IR/PT DLBCL cells. (B) Heat maps derived from reverse-phase protein array analyses of IR/PT DLBCL pairs represent the differential expression of proteins identified by Wilcoxon rank-sum test (red indicates above median; green indicates below median). (C) Western blot analyses for AKT and mTOR and its substrates show activity in IR/PT DLBCL cell pairs. (D) Western blot analysis for AKT, mTOR, and mTOR substrates in OCI-LY10-IbR cells 48 hours after electroporation with WT-BTK or empty vector. The upregulation of BTK in resistant clones reverses AKT and mTOR activation.