Background Hairy cell leukemia (HCL) is a well defined clinico-pathological entity whose underlying genetic lesion is still obscure. Methods We searched for HCL-associated mutations by massively parallel sequencing of the whole exome of leukemic and matched normal mononuclear cells purified from the peripheral blood of one patient with HCL. Results Whole exome sequencing identified 5 missense somatic clonal mutations that were confirmed at Sanger sequencing, including a heterozygous V600E mutation involving the BRAF gene. Since the BRAF V600E mutation is oncogenic in other tumors, further analyses were focused on this genetic lesion. Sanger sequencing detected mutated BRAF in 46/46 additional HCL patients (47/47 including the index case; 100%). None of the 193 peripheral B-cell lymphomas/leukemias other than HCL that were investigated carried the BRAF V600E mutation, including 36 cases of splenic marginal zone lymphomas and unclassifiable splenic lymphomas/leukemias. Immunohistological and Western blot studies showed that HCL cells express phospho-MEK and phospho-ERK (the downstream targets of the BRAF kinase), indicating a constitutive activation of the RAF-MEK-ERK mitogen-activated protein kinase pathway in HCL. In vitro incubation of BRAF-mutated primary leukemic cells from 5 HCL patients with PLX-4720, a specific inhibitor of active BRAF, led to marked decrease of phosphorylated ERK and MEK. Conclusions The BRAF V600E mutation was present in all HCL patients investigated. This finding may have relevant implications for the pathogenesis, diagnosis and targeted therapy of HCL (Funded by the Associazione Italiana Ricerca Cancro and others).

PET-2 overshadows the prognostic value of IPS and emerges as the single most important tool for planning of risk-adapted treatment in advanced HL.

Chronic lymphocytic leukemia (CLL) is a disease of the elderly, characterized by immunodeficiency. Hence, patients with CLL might be considered more susceptible to severe complications from COVID-19. We undertook this retrospective international multicenter study to characterize the course of COVID-19 in patients with CLL and identify potential predictors of outcome. Of 190 patients with CLL and confirmed COVID-19 diagnosed between 28/03/2020 and 22/05/2020, 151 (79%) presented with severe COVID-19 (need of oxygen and/or intensive care admission). Severe COVID-19 was associated with more advanced age (≥65 years) (odds ratio 3.72 [95% CI 1.79-7.71]). Only 60 patients (39.7%) with severe COVID-19 were receiving or had recent (≤12 months) treatment for CLL at the time of COVID-19 versus 30/39 (76.9%) patients with mild disease. Hospitalization rate for severe COVID-19 was lower (p < 0.05) for patients on ibrutinib versus those on other regimens or off treatment. Of 151 patients with severe disease, 55 (36.4%) succumbed versus only 1/38 (2.6%) with mild disease; age and comorbidities did not impact on mortality. In CLL, (1) COVID-19 severity increases with age; (2) antileukemic treatment (particularly BTK inhibitors) appears to exert a protective effect; (3) age and comorbidities did not impact on mortality, alluding to a relevant role of CLL and immunodeficiency.

The potassium channel Kv1.3 is highly expressed in the mitochondria of various cancerous cells. Here we show that direct inhibition of Kv1.3 using two mitochondria-targeted inhibitors alters mitochondrial function and leads to reactive oxygen species (ROS)-mediated death of even chemoresistant cells independently of p53 status. These inhibitors killed 98% of ex vivo primary chronic B-lymphocytic leukemia tumor cells while sparing healthy B cells. In orthotopic mouse models of melanoma and pancreatic ductal adenocarcinoma, the compounds reduced tumor size by more than 90% and 60%, respectively, while sparing immune and cardiac functions. Our work provides direct evidence that specific pharmacological targeting of a mitochondrial potassium channel can lead to ROS-mediated selective apoptosis of cancer cells in vivo, without causing significant side effects.

B cell chronic lymphocytic leukemia (B-CLL) is a neoplastic disorder characterized by accumulation of B lymphocytes due to uncontrolled growth and resistance to apoptosis. Analysis of B cells freshly isolated from 40 patients with chronic lymphocytic leukemia demonstrated that the Src kinase Lyn, the switch molecule that couples the B cell receptor to downstream signaling, displays anomalous properties. Lyn is remarkably overexpressed at the protein level in leukemic cells as compared with normal B lymphocytes, with a substantial aliquot of the kinase anomalously present in the cytosol. Whereas in normal B lymphocytes Lyn activation is dependent on B cell-receptor stimulation, in resting malignant cells, the constitutive activity of the kinase accounts for high basal protein tyrosine phosphorylation and low responsiveness to IgM ligation. Addition of the Lyn inhibitors PP2 and SU6656 to leukemic cell cultures restores cell apoptosis, and treatment of malignant cells with drugs that induce cell apoptosis decreases both activity and amount of the tyrosine kinase. These findings suggest a direct correlation between high basal Lyn activity and defects in the induction of apoptosis in leukemic cells. They also support a critical role for Lyn in B-CLL pathogenesis and identify this tyrosine kinase as a potential therapeutic target.

2016) Complex karyotypes and KRAS and POT1 mutations impact outcome in CLL after chlorambucilbased chemotherapy or chemoimmunotherapy. Blood, 128, 395-404.

© F e r r a t a S t o r t i F o u n d a t i o ncomparable, with different timing of the interim PET during the course of treatment and differing PET methodologies. Most studies used stand-alone PET, which has now been replaced by PET-CT. Reporting methods were not consistent making it difficult to judge how these results should be applied in clinical practice.In 2009 an international meeting attended by hematologists and nuclear medicine specialists was held in Deauville, France, with the intention of defining simple and reproducible criteria for interim-PET reporting in lymphoma.11 A five-point scale (5-PS) developed at Guy's and St. Thomas' Hospital in London was adopted 12 as the "Deauville criteria". An international study was launched to compare previous reports on the accuracy of interim PET in predicting treatment outcome in Hodgkin lymphoma with an international cohort of patients scanned using PET-CT after two cycles of ABVD and to evaluate the reproducibility of the 5-PS among reporters. The criteria for enrollment, the breakdown of patients according to stage (early unfavorable and advanced-stage) and the endpoints were the same as in the JID. Methods Retrieval of patients' dataConsecutive patients affected by Hodgkin lymphoma from participating centers worldwide diagnosed between January 2002 and December 2009 were retrospectively enrolled with the following inclusion criteria: (i) stage IIB to stage IVB or stage IIA Hodgkin lymphoma with adverse prognostic factors (at least three nodal sites involved, sub-diaphragmatic presentation, bulky disease, and erythrocyte sedimentation rate > 40 mm/h); (ii) treatment with four to eight cycles of ABVD with or without involved-field radiotherapy or consolidation radiotherapy; (iii) staging with PET/CT at baseline and after two courses of ABVD (PET-0 and PET-2, respectively); (iv) no change to treatment based on interim-PET results; and (v) a minimum follow-up of 1 year after completion of firstline treatment. Patients escalated to salvage treatment during ABVD chemotherapy were eligible only if the treatment change was based on clinical and/or radiological evidence of disease progression/resistance.The study was approved by the ethical committee of the coordinating center in Cuneo (Italy) and conducted according to the Helsinki declaration. Specific informed written consent was not required as all data were retrospectively collected in an anonymized format, in agreement with specific institutional and national requirements. AG, SC and ER analyzed the data and all co-authors had access to the primary data.Clinical data on 400 patients were collected; however only 335 paired scans (baseline and interim) were available for review. Of these, 75 were then excluded because there were no CT data (n=21), no baseline PET (n=25), no interim PET (n=1), missing CT slices (n=3), missing PET slices (n=10), poor quality PET images (n=6) or miscellaneous reasons (n=9). Complete data from 260 patients were available for analysis from 17 international academic institut...

The attraction of T lymphocytes into the pulmonary parenchyma represents an essential step in mechanisms ultimately leading to lung allograft rejection. In this study we evaluated whether IP-10 (CXCL10), a chemokine that is induced by interferon-gamma and stimulates the directional migration of activated T cells, plays a role in regulating the trafficking of effector T cells during lung allograft rejection episodes. Immunohistochemical examination showed that areas characterized by acute cellular rejection (grades 1 to 4) and active obliterative bronchiolitis (chronic rejection, Ca) were infiltrated by T cells expressing CXCR3, i.e., the specific receptor for CXCL10. In parallel, T cells accumulating in the bronchoalveolar lavage of lung transplant recipients with rejection episodes were CXCR3+ and exhibited a strong in vitro migratory capability in response to CXCL10. In lung biopsies, CXCL10 was abundantly expressed by graft-infiltrating macrophages and occasionally by epithelial cells. Alveolar macrophages expressed and secreted definite levels of CXCL10 capable of inducing chemotaxis of the CXCR3+ T-cell line 300-19; the secretory capability of alveolar macrophages was up-regulated by preincubation with interferon-gamma. Interestingly, striking levels of CXCR3 ligands could be demonstrated in the fluid component of the bronchoalveolar lavage in individuals with rejection episodes. These data indicate the role of the CXCR3/CXCL10 interactions in the recruitment of lymphocytes at sites of lung rejection and provide a rationale for the use of agents that block the CXCR3/CXCL10 axis in the treatment of lung allograft rejection.