MicroRNAs (miRNAs) are regulatory RNA molecules that are deregulated in many disease types, including cancer. Recently, miRNAs have shown promise as markers for cancer diagnosis. The aim of this study was to investigate whether serum miRNAs can be used as biomarkers for the detection of diffuse large B cell lymphoma (DLBCL). We measured the levels of miRNAs (miR-15a, miR-16-1, miR-21, miR-29c, miR-34a, miR-155, and miR-223) in serum samples from patients with DLBCL and healthy controls using real-time quantitative reverse-transcription polymerase chain reaction (qRT-PCR). We show here that miRNAs are present in human serum in a remarkably stable form. Four of miRNAs (miR-15a, miR-16-1, miR-29c, and miR-155) were significantly elevated in DLBCL serum when compared with normal controls (P < 0.05), while miR-34a was downregulated in DLBCL serum when compared with controls (P < 0.05). Receiver operating characteristic analyses reflects strong discriminating DLBCL from controls, with area under the curves of 0.7722, 0.7002, 0.6672, 0.8538, and 0.7157 for miR-15a, miR-16-1, miR-29c, miR-34a, and miR-155, respectively. At the cut-off value of 0.0006 for miR-15a, the sensitivity was 80% and the specificity was 76%; at the cut-off value of 0.0886 for miR-16-1, the sensitivity was 94% and the specificity was 51%; at the cut-off value of 1.395 for miR-34a, the sensitivity was 100% and the specificity was 70%; at the cut-off value of 0.0022 for miR-155, the sensitivity was 83% and the specificity was 65%. In conclusion, these data suggest that serum miRNAs are potentially useful tools as novel noninvasive biomarker for the diagnosis of DLBCL.

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Impaired cell death program has been noted as one of the hallmarks of chronic lymphocytic leukemia (CLL) and contributes to its accumulation of malignant monoclonal B cells as well as to chemotherapy resistance. A cell can die through the apoptosis or necrosis pathway. Recent investigations suggest that in apoptotic-deficient conditions, such as most types of cancer, a process of programmed necrosis, called necroptosis, prevails. However, the detailed molecular mechanisms underlying this alternative cell death pathway are still not fully understood. Here we demonstrate that CLL cells failed to undergo necroptosis upon stimulation of TNFa combined with pan-caspase inhibitor benzyloxycarbonyl-Val-Ala-Asp-fluoromethylketone (zVAD). Two core components of necroptotic machine, RIP3 and deubiquitinase cylindromatosis (CYLD), are markedly downregulated in CLL. Moreover, we identified lymphoid enhancer-binding factor 1 (LEF1), a downstream effector of the Wnt/b-catenin pathway, as a transcription repressor of CYLD in CLL. Knocking down LEF1 sensitizes CLL cells to TNFa/zVAD-induced necroptosis. The present investigation provides the first evidence that CLL cells have defects not only in apoptotic program but also in necroptotic signaling. Targeting the key regulators of necroptotic machine, such as LEF1, to restore this pathway may represent a novel approach for CLL treatment.