We searched the Basso Lymphoma dataset for 1944-12-3 patterns of 4EBP1 expression. One primary DLBCL specimen, out of 32 tested, had greatly reduced 4EBP1 mRNA expression relative to resting B lymphocytes and centroblasts. Therefore, 4EBP1 loss might occur in a fraction of primary human DLBCL tumors as observed in the VAL cell line. eIF4E expression in sample GSM44245 was higher than in normal B cells and similar to centroblasts. Nine other subtypes of B cell leukemia or lymphoma were analyzed in this dataset and none showed evidence for loss of 4EBP1 expression. Considering that there are three members of the 4EBP family, their tumor suppressor functions might be redundant. Of note, a very recent study showed that a large fraction of human pancreatic cancers lose expression of 4EBP1. However, 4EBP2 expression was not detected in pancreatic cancers or cell lines, a phenomenon that might facilitate tumor progression following 4EBP1 loss. In all B cell malignancies tested in the Basso Lymphoma microarray, 4EBP2 expression was similar to normal B cells. Increasing the 4EBP:eIF4E ratio rendered VAL cells more sensitive to asTORi-induced apoptosis, yet the magnitude of the cell death was still limited. Similarly, the pro-apoptotic 129-56-6 chemical information effects of MLN0128 and AZD8055 were modest in the DLBCL lines that expressed 4EBP1. These observations suggest that in isolation, mTOR kinase inhibition and disruption of eIF4F is generally insufficient to kill DLBCLs. In addition, there are likely to be other mechanisms of resistance to asTORi that are unrelated to the 4EBP:eIF4E ratio. Further investigations should focus on combination approaches that maximize the pro-apoptotic potential of mTOR inhibitors. Full length rat wild type 4EBP1 was obtained from Dr. John Lawrence. This construct was cloned into the pLVX-puro Dox inducible system using Not1 and EcoR1 restriction sites. High titer lentivirus was produced using the lentiviral packing and envelope constructs mentioned above. VAL a