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Genome wide association studies in cancer are used to understand the heritable genetic contribution to disease risk. Here, the authors perform a genome wide association study in European patients with acute myeloid leukemia and identify loci associated with risk of developing the disease.

Abstract TP53 aberrations predict chemoresistance and represent a contraindication for the use of standard chemoimmunotherapy in chronic lymphocytic leukaemia (CLL). Recent next‐generation sequencing (NGS)‐based studies have identified frequent low‐burden TP53 mutations with variant allele frequencies below 10%, but the clinical impact of these low‐burden TP53 mutations is still a matter of debate. In this study, we aimed to scrutinise the subclonal architecture and clinical impact of TP53 mutations using a sensitive, NGS‐based mutation analysis in a ‘real‐world’ cohort of 901 patients with CLL. In total, 225 TP53 mutations were identified in 17.5% (158/901) of the patients; 48% of these alterations represented high‐burden mutations, while 52% were low‐burden TP53 mutations. Low‐burden mutations as sole alterations were identified in 39% (62/158) of all mutated cases with 82% (51/62) of these being represented by a single low‐burden TP53 mutation. Patients harbouring low‐burden TP53 mutations had significantly lower time to first treatment compared to patients with wild‐type TP53. Our study has expanded the knowledge on the frequency, clonal architecture, and clinical impact of low‐burden TP53 mutations. By demonstrating that patients with sole low‐burden TP53 variants represent more than one‐third of patients with TP53 mutations and have an increased risk for treatment initiation, our findings strengthen the need to redefine the threshold of TP53 variant reporting to below 10% in the routine diagnostic setting.

Background: Ibrutinib is widely known as an effective and well-tolerated therapeutical choice of the chronic lymphocytic leukaemia (CLL). However, acquired resistance may occur during the treatment, causing relapse. Early detection of ibrutinib resistance is an important issue, therefore we aimed to find phenotypic markers on CLL cells the expression of which may correlate with the appearance of ibrutinib resistance.Methods: We examined 28 patients’ peripheral blood (PB) samples (treatment naïve, ibrutinib sensitive, clinically ibrutinib resistant). The surface markers’ expression (CD27, CD69, CD86, CD184, CD185) were measured by flow cytometry. Furthermore, the BTKC481S resistance mutation was assessed by digital droplet PCR. Moreover, the CLL cells’ phenotype of a patient with acquired ibrutinib resistance was observed during the ibrutinib treatment.Results: The expression of CD27 (p = 0.030) and CD86 (p = 0.031) became higher in the clinically resistant cohort than in the ibrutinib sensitive cohort. Besides, we found that high CD86 and CD27 expressions were accompanied by BTKC481S mutation. Our prospective study showed that the increase of the expression of CD27, CD69 and CD86 was noticed ahead of the clinical resistance with 3 months.Conclusion: Our study suggests that the changes of the expression of these markers could indicate ibrutinib resistance and the examination of these phenotypic changes may become a part of the patients’ follow-up in the future.

Pathologically increased vascular permeability is an important dysfunction in the pathomechanism of life-threatening conditions, such as sepsis, ischemia/reperfusion, or hereditary angioedema (HAE), diseases accompanied by uncontrolled activation of the complement system. HAE for example is caused by the deficiency of C1-inhibitor (the main regulator of early complement activation), which leads to edematous attacks threatening with circulatory collapse. We have previously reported that endothelial cells become activated during HAE attacks. A natural target of C1-inhibitor is mannan-binding lectin-associated serine protease-1 (MASP-1), a multifunctional serine protease, which plays a key role in the activation of complement lectin pathway. We have previously shown that MASP-1 induces the pro-inflammatory activation of endothelial cells and in this study we investigated whether MASP-1 can directly affect endothelial permeability. All experiments were performed on human umbilical vein endothelial cells (HUVECs). Real-time micro electric sensing revealed that MASP-1 decreases the impedance of HUVEC monolayers and in a recently developed permeability test (XperT), MASP-1 dose-dependently increased endothelial paracellular transport. We show that protease activated receptor-1 mediated intracellular Ca2+-mobilization, Rho-kinase activation dependent myosin light chain (MLC) phosphorylation, cytoskeletal actin rearrangement, and disruption of interendothelial junctions are underlying this phenomenon. Furthermore, in a whole-transcriptome microarray analysis MASP-1 significantly changed the expression of 25 permeability-related genes in HUVECs—for example it up-regulated bradykinin B2 receptor expression. According to our results, MASP-1 has potent permeability increasing effects. During infections or injuries MASP-1 may help eliminate the microbes and/or tissue debris by enhancing the extravasation of soluble and cellular components of the immune system, however, it may also play a role in the pathomechanism of diseases, where edema formation and complement lectin pathway activation are simultaneously present. Our findings also raise the possibility that MASP-1 may be a promising target of anti-edema drug development.

Background. Transforming growth factor-β (TGFβ)-induced epithelial–myofibroblast transdifferentiation is a central mechanism contributing to the pathogenesis of progressive tubulo-interstitial fibrosis. We wanted to dissect the role of extracellular signal-regulated protein kinase (ERK1,2), p38 mitogen-activated protein kinase (p38 MAPK) and the receptor-regulated Smad proteins in the regulation of α-smooth muscle cell actin (αSMA) expression, a hallmark of myofibroblast formation, induced by TGFβ in renal proximal tubular cells. Methods. Activation of signalling molecules was assessed by western blotting using phospho-specific antibodies. To specifically interfere with signalling cascades, porcine proximal tubular cells (LLC-PK/AT1) were infected with recombinant replication-deficient adenoviruses. In other experiments, specific kinase inhibitors were used. The αSMA synthesis was assessed by western blotting or immunofluorescent staining of cellular αSMA. To assess the regulation of the αSMA promoter, tubular cells were transiently transfected with a 785 bp αSMA promoter–luciferase reporter construct and vectors interfering with the Smad pathway. Results. Blocking ERK1,2 activation with PD98059 or p38 MAPK with SB 203580 potently inhibited the TGFβ-induced αSMA synthesis in renal tubular cells. Adenoviral expression of dominant negative (DN) p38β but not of p38α potently inhibited αSMA expression. Furthermore, adenoviral expression of DN MKK6b but not of DN MKK3b caused a substantial inhibition of the TGFβ effect, confirming the role of p38β in the regulation of TGFβ-induced αSMA expression. Finally, inhibiting the Smad pathway with adenovirally delivered Smad7 and DN Smad3 also blocked TGFβ-induced αSMA synthesis. Conclusion. TGFβ-induced αSMA expression is regulated by the coordinated activation of a complex system of parallel MAPK and Smad signalling pathways in renal proximal tubular cells during epithelial–mesenchymal transdifferentiation. [ABSTRACT FROM AUTHOR]