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Acute lymphoblastic leukemias (ALL) are characterized by a large number of cytogenetic abnormalities of clinical interest that require the use of several complementary techniques. Optical genome mapping (OGM) is based on analysis of ultra-high molecular weight DNA molecules that provides a high-resolution genome-wide analysis highlighting copy number and structural anomalies, including balanced translocations.We compared OGM to standard techniques (karyotyping, fluorescent in situ hybridization, single nucleotide polymorphism-array and reverse transcription multiplex ligation-dependent probe amplification) in 10 selected B or T-ALL. Eighty abnormalities were found using standard techniques of which 72 (90%) were correctly detected using OGM. Eight discrepancies were identified, while 12 additional anomalies were found by OGM. Among the discrepancies, four were detected in raw data but not retained because of filtering issues. However, four were truly missed, either because of a low variant allele frequency or because of a low coverage of some regions. Of the additional anomalies revealed by OGM, seven were confirmed by another technique, some of which are recurrent in ALL such as LMO2-TRA and MYC-TRB fusions. Despite false positive anomalies due to background noise and a case of inter-sample contamination secondarily identified, the OGM technology was relatively simple to use with little practice. Thus, OGM represents a promising alternative to cytogenetic techniques currently performed for ALL characterization. It enables a time and cost effective analysis allowing identification of complex cytogenetic events, including those currently inaccessible to standard techniques. K E Y W O R D S acute lymphoblastic leukemia, chromosome mapping, cytogenetics, optical genome mapping 1 | INTRODUCTION Acute lymphoblastic leukemias (ALLs) are neoplasms resulting from an early blockage of cells committed to B or T-lymphoid lineage.Although rare (1.7 cases/year/100000 inhabitants) in the general population, they are the most common cancer in children, with an incidence approximately three times higher than in adults. 1 ALLs are pathologies of great genetic diversity 2-4 which routinely require the

Hereditary xerocytosis is a rare red blood cell disease related to gain-of-function mutations in the FAM38A gene, encoding PIEZO1, in 90% of cases; PIEZO1 is a broadly expressed mechano-transducer that plays a major role in many cell systems and tissues that respond to mechanical stress. In erythrocytes, PIEZO1 adapts the intracellular ionic content and cell hydration status to the mechanical constraints induced by the environment. Until recently, the pathophysiology of hereditary xerocytosis was mainly believed to be based on the "PIEZO1-Gardos channel axis" in erythrocytes, according to which PIEZO1-activating mutations induce a calcium influx that secondarily activates the Gardos channel, leading to potassium and water efflux and subsequently to red blood cell dehydration. However, recent studies have demonstrated additional roles for PIEZO1 during early erythropoiesis and reticulocyte maturation, as well as roles in other tissues and cells such as lymphatic vessels, hepatocytes, macrophages and platelets that may affect the pathophysiology of the disease. These findings, presented and discussed in this review, broaden our understanding of hereditary xerocytosis beyond that of primarily being a red blood cell disease and identify potential therapeutic targets. | INTRODUCTIONThe PIEZO proteins are a family of mechano-transducers first described in a neuron derived cell line in 2010. 1 The two members are PIEZO1, encoded by FAM38A on chromosome 16, and PIEZO2, encoded by FAM38B on chromosome 18. They are expressed in many tissues. 1,2 The structure of PIEZO1 has been recently elucidated. A first description of the murine protein revealed its three-dimensional structure, consisting of a three-bladed homotrimeric transmembrane helix completed by an extracellular cap. An intra-cytoplasmic domain, split into three parts, called "beams," extends from the transmembrane domain. The C-terminal end of each monomer has an extracellular domain (ECD), which forms the cap, and an intracellular domain (CTD), which appears to be connected to the paddles by the beams and closes the inner ion pore (Figure 1). The assembly provides a hydrophilic central transmembrane duct bordered by six helices that allows the passage of ions. Thus PIEZO1 constitutes a mechanosensitive ion channel due to the flexibility of the three blades. 1 Deformation of the plasma membrane subsequent to mechanical stimulation induces rotation of the PIEZO1 blades, transmitting such deformation to the ECD and CTD domains, allowing the ion channel to open using a lever-like mechanism. 2 When a compressive force is applied parallel to the axis of the ion channel, it induces lateral membrane tension, resulting in flattening and widening of PIEZO1, which causes the pore to open and allows the passage of ions. Such deformations are reversible, and PIEZO1 returns rapidly to its original conformation. [3][4][5] After opening, PIEZO1 acts as a passive channel for mono/divalent cations depending on their extracellular-intracellular Nicolas Jankovsky and Alexis Caulier...

B-chronic lymphocytic leukemia (B-CLL), the most common human leukemia, is characterized by predominantly non-dividing malignant mature CD5+ B lymphocytes with an apoptosis defect. Various microenvironmental stimuli confer a growth advantage on these leukemic cells and extend their survival in vivo. Nevertheless, when cultured in vitro, CLL B-cells rapidly die from apoptosis. Certain cytokines may extend the survival capacity of CLL B-cells in vitro and individual anti-apoptotic effects of several cytokines have been reported. The potential cumulative effect of such cytokines has not been studied. We therefore investigated the effects on CLL B-cells survival in vitro of humoral factors, polyclonal lymphocyte activators and a combination of cytokines known for their anti-apoptotic effects. Purified CLL B-cells were cultured in the presence or absence of various soluble molecules and the leukemic cell response was assessed in terms of viability. Apoptotic cell death was detected by flow cytometry using annexinV and 7-amino-actinomycin. The survival of CLL B-cells in vitro was highly variable. When tested separately, cytokines (IL-2, -6, -10, -12, -15, -21, BAFF and APRIL) improved CLL B cell survival moderately; in combination, they significantly enhanced survival of these cells, even up to 7 days of culture. We also report that humoral factors from autologous serum are important for survival of these malignant cells. Our findings support the concept that the CLL microenvironment is critical and suggest that soluble factors may contribute directly to the prolonged survival of CLL B-cells. Therefore, the combination of cytokines we describe as providing strong resistance to apoptosis in vitro might be used to improve the treatment of CLL.

Although hepatocellular carcinoma (HCC) is one of the most common malignancies and constitutes the third leading cause of cancer-related deaths, the underlying molecular mechanisms are not fully understood. In the present study, we demonstrate for the first time that hepatocytes express signalling lymphocytic activation molecule family member 3 (SLAMF3/CD229) but not other SLAMF members. We provide evidence to show that SLAMF3 is involved in the control of hepatocyte proliferation and in hepatocellular carcinogenesis. SLAMF3 expression is significantly lower in primary human HCC samples and HCC cell lines than in human healthy primary hepatocytes. In HCC cell lines, the restoration of high levels of SLAMF3 expression inhibited cell proliferation and migration and enhanced apoptosis. Furthermore, SLAMF3 expression was associated with inhibition of HCC xenograft progression in the nude mouse model. The restoration of SLAMF3 expression levels also decreased the phosphorylation of MAPK ERK1/2, JNK and mTOR. In samples from resected HCC patients, SLAMF3 expression levels were significantly lower in tumorous tissues than in peritumoral tissues. Our results identify SLAMF3 as a specific marker of normal hepatocytes and provide evidence for its potential role in the control of proliferation of HCC cells.