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Summary Gain-of-function Notch mutations are recurrent in mature small B cell lymphomas such as mantle cell lymphoma (MCL) and chronic lymphocytic leukemia (CLL), but the Notch target genes that contribute to B cell oncogenesis are largely unknown. We performed integrative analysis of Notch-regulated transcripts, genomic binding of Notch transcription complexes, and genome conformation data to identify direct Notch target genes in MCL cell lines. This B cell Notch regulome is largely controlled through Notch-bound distal enhancers and includes genes involved in B cell receptor and cytokine signaling and the oncogene MYC , which sustains proliferation of Notch-dependent MCL cell lines via a Notch-regulated lineage-restricted enhancer complex. Expression of direct Notch target genes is associated with Notch activity in an MCL xenograft model and in CLL lymph node biopsies. Our findings provide key insights into the role of Notch in MCL and other B cell malignancies and have important implications for therapeutic targeting of Notch-dependent oncogenic pathways. [ABSTRACT FROM AUTHOR]

The sphingosine-1-phosphate/Endothelial Differentiation Gene (S1P/EDG) family of G-protein-coupled receptors (GPCR) currently includes five different isoforms, which differentially regulate fundamental cellular processes such as migration, proliferation, cytoskeletal organization, adherens junction assembly and morphogenesis. Additionally, specific S1P/EDG isoforms can regulate important physiological processes such as blood vessel maturation, cardiac development and angiogenesis in vivo. Herein, we review the current state of knowledge of the expression patterns, signaling pathways and functional characteristics of the different S1P receptors. Further investigation in this field will likely improve our understanding of cardiovascular development as well as vascular diseases and may lead to novel therapeutic approaches. [Copyright &y& Elsevier]

Characterization of gross chromosomal rearrangements, particularly translocations in neoplasms, has proven to be valuable in patient management by aiding in diagnosis, defining prognosis, and leading to new therapeutic interventions. In this report, we investigate two apparently balanced translocations, t(6;17)(q23.3;p13.3) and t(2;13)(p21;q14.11), in patients with myeloid neoplasms and uncover concomitant microdeletions associated with the breakpoints. Breakpoint mapping by fluorescence in situ hybridization (FISH) detected deletions at or adjacent to all breakpoints. Subsequently, array comparative genomic hybridization on the 244K Agilent platform refined the deletion boundaries, revealing a 1.7 Mb deletion directly adjacent to the 6q23.3 breakpoint, and a 562 kb deletion at 17p13.3 in the first case. The second case was found to harbor a 195 kb deletion at 2p21 and a 1.4 Mb deletion distal to the 13q breakpoint at 13q14.3. Additionally, a 133 kb deletion within the breakpoint region at 13q14.11 and a 265 kb deletion proximal to the breakpoint were discovered, neither of which was detected by FISH. Although a gene fusion resulting from either novel rearrangement cannot be determined from these data, formation of a fusion transcript cannot be excluded because the resolution of the techniques used does not allow definite delineation of the breakpoint locations. Although the incidence and clinical relevance of these focal imbalances remains to be evaluated, the cases presented here support high resolution evaluation of presumably balanced rearrangements in neoplasms. Such imbalances may portend important hitherto unrecognized prognostic and diagnostic categories. [ABSTRACT FROM AUTHOR]

The presence of JAK2 exon 12 mutation was included by the 2016 World Health Organization (WHO) Classification as one of the major criteria for diagnosing polycythemia vera (PV). Few studies have evaluated the clinical presentation and bone marrow morphology of these patients and it is unclear if these patients fulfill the newly published criteria of 5th edition WHO or The International Consensus Classification (ICC) criteria for PV. Forty-three patients with JAK2 exon 12 mutations were identified from the files of 7 large academic institutions. Twenty patients had complete CBC and BM data at disease onset. Fourteen patients met the diagnostic criteria for PV and the remaining six patients were diagnosed as MPN-U. At diagnosis, 9/14 patients had normal WBC and platelet counts (isolated erythrocytosis/IE subset); while 5/14 had elevated WBC and/or platelets (polycythemic /P subset). We found that hemoglobin and hematocrit tended to be lower in the polycythemia group. Regardless of presentation (P vs IE), JAK2 deletion commonly occurred in amino acids 541–544 (62 %). MPN-U patients carried JAK2 exon 12 mutation, but did not fulfill the criteria for PV. Half of the patients had hemoglobin/hematocrit below the diagnostic threshold for PV, but showed increased red blood cell count with low mean corpuscular volume (56–60 fL). Three cases lacked evidence of bone marrow hypercellularity. In summary, the future diagnostic criteria for PV may require a modification to account for the variant CBC and BM findings in some patients with JAK2 exon 12 mutation. • A significant proportion of studied patients with JAK2 exon 12 mutation did not fulfill the current WHO/ICC criteria for PV. • JAK2 exon 12 analysis is required in all patients with elevated RBC values when JAK2 V617F mutation is negative. • Awareness of the variable bone marrow morphology findings in PV remains key to correct diagnosis. [ABSTRACT FROM AUTHOR]

Cutaneous SCC (cSCC) is the most frequently occuring skin cancer with metastatic potential and can manifest rapidly as a common side effect in patients receiving systemic kinase inhibitors. Here, we use massively parallel exome and targeted level sequencing of 132 sporadic cSCCs and of 39 squamoproliferative lesions and cSCCs arising in patients receiving the BRAF inhibitor vemurafenib, as well as 10 normal skin samples, to identify NOTCH1 mutation as an early event in squamous cell carcinogenesis. Bisected vemurafenib-induced lesions revealed surprising heterogeneity with different activating HRAS and NOTCH1 mutations identified in two halves of the same cSCC, suggesting polyclonal origin. Immunohistochemical analysis using an antibody specific to nuclear NOTCH1 correlates with mutation status in sporadic cSCCs, and regions of NOTCH1 loss or downregulation are frequently observed in normal-looking skin. Our data indicate that NOTCH1 acts as a gatekeeper in human cSCC. [ABSTRACT FROM AUTHOR]