CML in the very elderly: the impact of comorbidities and TKI selection in a real-life multicenter study.

Tyrosine kinase inhibitors (TKIs) have greatly improved chronic myeloid leukemia (CML) treatments, with survival rates close to the general population. Yet, for the very elderly, robust data remains limited. This study focused on assessing comorbidities, treatment approaches, responses, and survival for elderly CML patients. Our study was conducted on 123 elderly (≥ 75 years) CML patients across four centers in Israel and Moffitt Cancer Center, USA. The median age at diagnosis was 79.1 years, with 44.7% being octogenarians. Comorbidities were very common; cardiovascular risk factors (60%), cardiovascular diseases (42%), with a median age-adjusted Charlson Comorbidity Index (aaCCI) of 5. Imatinib was the leading first-line therapy (69%), while the use of second-generation TKIs increased post-2010. Most patients achieved a major molecular response (MMR, 66.7%), and half achieved a deep molecular response (DMR, 50.4%). Over half (52.8%) of patients moved to second-line, and nearly a quarter (23.5%) to third-line treatments, primarily due to intolerance. Overall survival (OS) was notably longer in patients with an aaCCI score below 5, and in patients who attained DMR. Contrary to expectations, the Israeli cohort showed a shorter actual life expectancy than projected, suggesting a larger impact of CML on elderly survival. In summary, imatinib remains the main initial treatment, but second-generation TKIs are on the rise among elderly CML patients. Outcomes in elderly CML patients depend on comorbidities, TKI type, response, and age, underscoring the need for personalized therapy and additional research on TKI effectiveness and safety.

STAT3 Activates the Pentraxin 3 Gene in Chronic Lymphocytic Leukemia Cells.

Pentraxin-related protein 3 (PTX3), commonly produced by myeloid and endothelial cells, is a humoral pattern recognition protein of the innate immune system. Because PTX3 plasma levels of patients with chronic lymphocytic leukemia (CLL) are high and most circulating cells in patients with CLL are CLL cells, we reasoned that CLL cells produce PTX3. Western immunoblotting revealed that low-density cells from seven of seven patients with CLL produce high levels of PTX3, flow cytometry analysis revealed that the PTX3-producing cells are B lymphocytes coexpressing CD19 and CD5, and confocal microscopy showed that PTX3 is present in the cytoplasm of CLL cells. Because STAT3 is constitutively activated in CLL cells, and because we identified putative STAT3 binding sites within the PTX3 gene promoter, we postulated that phosphorylated STAT3 triggers transcriptional activation of PTX3. Immunoprecipitation analysis of CLL cells' chromatin fragments showed that STAT3 Abs precipitated PTX3 DNA. STAT3 knockdown induced a marked reduction in PTX3 expression, indicating a STAT3-induced transcriptional activation of the PTX3 gene in CLL cells. Using an EMSA, we established and used a dual-reporter luciferase assay to confirm that STAT3 binds the PTX3 gene promoter. Downregulation of PTX3 enhanced apoptosis of CLL cells, suggesting that inhibition of PTX3 might benefit patients with CLL.

Using natural killer cell-derived exosomes as a cell-free therapy for leukemia.

Natural killer (NK) cells are components of the innate immune system which play a pivotal role in cancer cell surveillance. Despite promising results in clinical trials, the use of NK-based therapies is limited due to unsatisfactory efficiencies and safety issues. In recent years, exosomes have emerged as a powerful, natural therapeutic tool. Since exosomes are known to carry cargos that reflect the cellular makeup of their cell of origin, we were prompted to test whether NK-derived exosomes (NKexo) maintain the anti-leukemia capacity of NK-cells. We found NK92MI-cells to secrete large amounts of 100-200 nm cap-shaped particles expressing exosomal and NK biomarkers (CD63, CD81, CD56). We demonstrated that NKexo exert a potent, selective, anti-leukemia effect on all leukemia cell-lines tested. Furthermore, NKexo eliminated leukemia cells isolated from patients with acute and chronic leukemia and inhibited hematopoietic colony growth. While leukemia cells were targeted and severely affected by NKexo, healthy B-cells remained unaffected, indicating a selective effect. This selectivity was further confirmed by demonstrating that NKexo were specifically taken up by leukemic cells but not by healthy B-cells. Our in vivo data support our in vitro and ex vivo findings and demonstrate improved human-CD45+ leukemia blast counts and overall survival in NKexo treated humanized acute myeloid leukemia (HL-60) xenograft mice thus supporting the assumption that NKexo possess an anti-leukemia effect. Pending further analyses, our findings provide the pre-clinical evidence needed to test the NKexo approach in future pre-clinical and clinical studies to ultimately develop an acellular "off-the-shelf" product to treat leukemia.

The role of additional chemotherapy prior to autologous HCT in patients with relapse/refractory DLBCL in partial remission-A retrospective multicenter study.

OBJECTIVES: To evaluate the role of additional chemotherapy before autologous hematopoietic cell transplantation (HCT) in patients with relapse/refractory diffuse large B-cell lymphoma (DLBCL) who achieve partial remission following first salvage therapy. METHODS: We conducted a multicenter retrospective study of all adult patients with DLBCL who underwent HCT between 2008 and 2020 and achieved partial response (PR) after the first salvage and were either referred directly to HCT (n = 47) or received additional salvage therapy before HCT (n = 22). RESULTS: Post-HCT CR rate and progression-free survival were comparable between the two groups (66% vs. 68%, p = .86 and median not reached vs. 10.2 months [95% confidence interval, CI 7.1-12.3], p = .27, respectively). Median overall survival (OS) and estimated 3-year OS favored patients who were directly referred to HCT (105.8 [95% CI 63-148] months vs. 14.5 [95% CI 0-44] months, p = .035, and 65% [95% CI 51%-75%] vs. 40% [95% CI 21%-53%], p = .035, respectively). In Cox regression model, while International Prognostic Index and primary refractory versus relapse disease did not impact OS, allocation to a second salvage regimen and older age were both associated with inferior survival (hazard ratio [HR] = 2.57 95% CI 1.1-5.8, p = .023 and HR = 1.04 95% CI 0.99-1.2, p = .064, respectively). CONCLUSIONS: Referring patients with chemotherapy-sensitive disease in PR directly to HCT is associated with better OS compared to those receiving additional lines of treatment.

Humoral serological response to the BNT162b2 vaccine is abrogated in lymphoma patients within the first 12 months following treatment with anti-CD2O antibodies.

Patients with lymphoma, especially those treated with anti-CD20 monoclonal antibodies, suffer high COVID-19-associated morbidity and mortality. The goal of this study was to assess the ability of lymphoma patients to generate a sufficient humoral response after two injections of BNT162b2 Pfizer vaccine and to identify factors influencing the response. Antibody titers were measured with the SARS-CoV-2 IgG II Quant (Abbott ) assay in blood samples drawn from lymphoma patients 4 2 weeks after the second dose of vaccine. The cutoff for a positive response was set at 50 AU/mL. Positive serological responses were observed in 51% of the 162 patients enrolled in this cross-sectional study. In a multivariate analysis, an interval of <12 months between the last anti-CD20 monoclonal antibody dose and the second vaccine dose (odds ratio=31.3 [95% confidence interval: 8.4-116.9], P<0.001) and presence of active lymphoma (odds ratio=4.2 (95% confidence interval: 2.1- 8.2), P=0.006) were identified as negative response predictors. The rate of seropositivity increased from 3% in patients vaccinated within 45 days after the last monoclonal antibody administration to 80% in patients vaccinated >1 year after this therapy. The latter percentage was equal to that of patients never exposed to monoclonal antibodies. In conclusion, lymphoma patients, especially those recently treated with anti- CD20 monoclonal antibodies, fail to develop sufficient humoral response to BNT162b2 vaccine. While a serological response is not the only predictor of immunity, its low level could make this population more vulnerable to COVID-19, which implies the need for a different vaccination schedule for such patients.

STAT3-Induced Wnt5a Provides Chronic Lymphocytic Leukemia Cells with Survival Advantage.

The wingless and integration site growth factor-5a (Wnt5a) is a ligand of the receptor tyrosine kinase-like orphan receptor-1 (ROR1). Because both Wnt5a and ROR1 are expressed in circulating chronic lymphocytic leukemia (CLL) cells, and because in other cell types, STAT3, which is constitutively activated in CLL, induces Wnt5a signaling, we wondered whether STAT3 induces the expression of Wnt5a in CLL cells. Sequence analysis detected four putative STAT3 binding sites in close proximity to the Wnt5a gene promoter's start codon. Chromatin immunoprecipitation and EMSA revealed that STAT3 binds to the Wnt5a gene promoter, and a luciferase assay showed that STAT3 activates the Wnt5a gene. Additionally, transfection of peripheral blood CLL cells with STAT3 short hairpin RNA downregulated Wnt5a mRNA and protein levels, suggesting that STAT3 binds to the Wnt5a gene promoter and induces the expression of Wnt5a in CLL cells. Flow cytometry and confocal microscopy determined that both Wnt5a and its receptor ROR1 are coexpressed on the surface of CLL cells, and Western immunoblotting showed an inverse correlation between Wnt5a and ROR1 protein levels, implying that, regardless of CLL cells' ROR1 levels, blocking the interaction between Wnt5a and ROR1 might be beneficial to patients with CLL. Indeed, transfection of CLL cells with Wnt5a small interfering RNA reduced Wnt5a mRNA and protein levels and significantly increased the spontaneous apoptotic rate of CLL cells. Taken together, our data unravel an autonomous STAT3-driven prosurvival circuit that provides circulating CLL cells with a microenvironment-independent survival advantage.

Thrombin Generation in Patients with Atrial Fibrillation Undergoing Percutaneous Coronary Intervention.

BACKGROUND: The optimal antithrombotic treatment for patients with atrial fibrillation (AF) that undergo percutaneous coronary intervention (PCI) is controversial. Dual therapy (clopidogrel and a direct oral anticoagulant [DOAC]) is safer than triple therapy (warfarin, aspirin, and clopidogrel), while efficacy is unclear. We aimed to evaluate thrombin generation (TG) under dual and triple therapy. METHODS: A noninterventional prospective trial in patients with AF undergoing PCI. Patients received 4 weeks of triple therapy with aspirin, clopidogrel, and a DOAC followed by aspirin withdrawal. TG was measured in platelet-rich plasma (PRP) and platelet-poor plasma (PPP) at 3 five to 21 points, day 1 after PCI (TIME 0), 4 weeks after PCI (TIME 1), and 2 weeks after aspirin withdrawal (TIME 2). RESULTS: Twenty-three patients (18 men, median age 78 years, 83% with acute coronary syndrome) were included. Endogenous thrombin potential (ETP) in PPP was high at TIME 0 compared with TIME 1 (ETP 3,178 ± 248 nM vs. 2,378 ± 222 nM, p = 0.005). These results remained consistent when measured in PRP. No significant difference in ETP was found before (TIME 1) and after aspirin withdrawal (TIME 2) although few patients had high ETP levels after stopping aspirin. CONCLUSIONS: TG potential is high immediately after PCI and decreases 4 weeks after PCI in patients receiving triple therapy. TG remains constant after aspirin withdrawal in most patients, suggesting that after 1 month the antithrombotic effect of dual therapy may be similar to triple therapy.

Anticoagulation in patients with atrial fibrillation, thrombocytopenia and hematological malignancy.

Managing anticoagulation in hematological malignancy patients with atrial fibrillation and thrombocytopenia is a clinical challenge with limited data. We aimed to identify anticoagulation management strategies and evaluate bleeding and thrombosis rates associated with each approach. A retrospective cohort study in Israel and the Netherlands was conducted. Patients with hematological malignancy and atrial fibrillation were indexed when platelets were < 50 × 109/L and followed for 30 days. The cohort included 61 patients of whom 42 (69%) had anticoagulation held at index. On multivariate analysis, holding anticoagulation was associated with age < 65 years and atrial fibrillation diagnosed within 30 days prior index. Clinically relevant bleeding was diagnosed in 7 (16.7%) and 1 (5.3%) of patients who had anticoagulation held and continued respectively, while arterial thromboembolism occurred in 1 patient in each group (2.4% and 5.3%, respectively). All-cause mortality rate was high at 45%. Accordingly, the 30-day bleeding risk may outweigh the risk of arterial thromboembolism in hematological malignancy, platelets < 50 × 109/L and atrial fibrillation.

Risk factors for high-dose methotrexate associated acute kidney injury in patients with hematological malignancies.

High dose methotrexate (HDMTX)-induced acute kidney injury (AKI) is a well-known adverse event in hemato-oncology patients. Our purpose was to define factors and setup cut-offs that may help better identify patients at-risk for developing AKI following HDMTX. All consecutive patients who received MTX dose ≥1 g were retrospectively reviewed. We compared patients with or without renal toxicity. We used a logistic regression model to define baseline variables associated with AKI. Overall survival (OS) was estimated by the Kaplan-Meier method employing log-rank test. Between 2012 and 2017, 160 patients were included with a total of 265 courses. Indications included: primary central nervous system (CNS) lymphoma, CNS prophylaxis in other lymphoma types, acute lymphatic leukemia and others. Median age at diagnosis was 58 years (range, 18-84), 54% were males, median MTX dose was 1941 mg/m2 (range, 743-5442) and AKI developed in 9% of drug administrations (n = 24). In univariate analysis: age > 40, LDH > 380 units/L, eGFR < 112 mL/min, albumin <3.6 mg/dL at baseline and Charlson comorbidity index (CCI) were associated with AKI. In multivariable analysis, only LDH > 380 units/L (OR = 4.1, 95% confidence interval [CI] 1.04-20.9, P = .04) and albumin levels <3.6 g/dL (OR = 4.17, 95% CI 1.04-6.5, P = .04) remained significant. In patients with AKI, median drug elimination was longer (8 days vs 5 days). In 80% of cases, the creatinine levels returned to normal within 1 month. Yet, the median survival of patients who developed AKI was 37 months, compared to 145 months in patients without AKI (Log rank = 0.015). In conclusion, LDH > 380 units/L and albumin <3.6 g/dL were the strongest factors associated with AKI in patients receiving HDMTX. Although the rise in creatinine levels was almost uniformly reversible, AKI was associated with increased mortality rates.

Sequential treatment with FLAG-IDA/treosulfan conditioning regimen for patients with active acute myeloid leukemia.

Sequential protocols combining salvage chemotherapy with reduced intensity conditioning (RIC) and allogeneic hematopoietic cell transplantation (alloHCT) for high-risk acute myeloid leukemia (AML) have been studied more than a decade. Purpose of this retrospective analysis was to evaluate the anti-leukemic efficacy and toxicity of FLAG-IDA protocol (fludarabine, cytarabine, and idarubicin) followed by treosulfan-based conditioning for patients with active AML. From January 2014 to November 2019, a total of 29 active AML patients [median age, 64 years (range, 23-73)] were treated. All patients completed protocol regimen and were transplanted. Five patients (17%) had grade 3-4 toxicities; therefore, treosulfan was substituted with total body irradiation (TBI) non-myeloablative conditioning. Six (20%) patients died within 30 post-transplant days, all from infectious complications. Out of 23 evaluable patients on day 30, 22 (96%) achieved complete hematologic remission with full donor chimerism. Non-relapse mortality (NRM) rates at 1 and 3 years were 22% and 49%, respectively. Median overall survival (OS) was 12 (95% CI, 4-20) months. OS and disease-free survival were 50% and 46% at 1 year and 28% and 17% at 2 years, respectively. Age, gender, disease burden, number of previous lines, and comorbidity score did not predict survival. Sequential strategy combining FLAG-IDA and treosulfan may offer a salvage option for few selected patients with active AML; however, high NRM presents a major obstacle to treatment success. Future efforts should focus on reducing NRM by moderating regimen intensity and by better selection of patients.

Epidural/spinal anesthesia during delivery in women with factor XI deficiency, a single center experience.

INTRODUCTION: The safety of neuro-axial anaesthesia (epidural/spinal) at labour of women with partial factor XI (FXI) deficiency is uncertain. Although FXI deficiency is frequent in Ashkenazi Jews, it is not routinely measured before labour. Our institute serves a large Ashkenazi population. We assumed that 10% of them have undiagnosed FXI deficiency. AIM: Assess the incidence, bleeding tendency and coagulation status among Jewish Ashkenazi women with FXI deficiency that underwent neuro-axial anaesthesia at delivery. METHODS: Jewish Ashkenazi women who underwent neuro-axial anaesthesia at labour completed the SSC ISTH bleeding assessment tool (BAT) and had blood drawn for coagulation tests, FXI and thrombin generation after labour. Estimation for 10 years was calculated from the 1-year sample. RESULTS: We recruited 261 women during 12 months. Among them, 39 (15%) had FXI deficiency (<70%) with median FXI levels of 63% (range: 33%-70%). Around 50% of them underwent amniocentesis in the current pregnancy and prior neuro-axial anaesthesia with no bleeding complications. BAT score and thrombin generation did not differ between women regardless of FXI status. aPTT was longer in women with partial FXI deficiency (median - 28.6 sec vs 26.3 sec, P < .001, Table 2), although within the normal range in all women. No bleeding complications after neuro-axial anaesthesia at delivery were reported in our centre in the last decade though, and according to our estimation, at least 2150 women had partial FXI deficiency. CONCLUSIONS: A significant number of Jewish Ashkenazi women with undiagnosed partial FXI deficiency undergo neuro-axial anaesthesia at labour without bleeding complications.

Romidepsin treatment for relapsed or refractory peripheral and cutaneous T-cell lymphoma: Real-life data from a national multicenter observational study.

Romidepsin is a class I selective histone deacetylase (HDAC) inhibitor approved by the Food and Drug Administration (FDA) for relapsed/refractory (R/R) cutaneous T-cell lymphoma (CTCL) and peripheral T-cell lymphoma (PTCL), treated with at least one prior systemic therapy. Currently, there is paucity of real-life data on the efficacy and safety of romidepsin in R/R T-cell lymphoma. This national, multicenter study presents real-life data on the efficacy and safety of romidepsin in R/R T-cell lymphoma. Patients diagnosed and treated with romidepsin for R/R CTCL or PTCL between 2013 and 2018 were retrospectively reviewed. Outcomes included overall survival (OS), event-free survival (EFS), overall response rate (ORR), complete response (CR), and adverse events. Fifty-three patients with R/R PTCL (n = 42) or CTCL (n = 11) were included. Among CTCL patients, median OS was not reached, ORR was 25%, and none achieved CR. Among PTCL patients, median OS was 7.1 months, EFS was 1.9 months, ORR rate was 33%, and 12.5% achieved CR. In a univariate analysis, predictors for longer EFS include any response to therapy, number of previous lines, and PTCL subclass (with better results for angioimmunobalstic T-cell lymphoma). In a univariate and multivariate analysis for OS, treatment response was the only factor predicting OS (OR 4.48; CI 95%, 1.57-12.79; P = .005). Most grade 3 and 4 adverse events were hematological (35%). Infections were reported in 34% of patients. This real-life experience with romidepsin confirms the results of the pivotal phase II trials. PTCL subtype and the number of previous lines of therapy have an impact on EFS. In addition, patients who had good response to romidepsin benefited most in terms of both EFS and OS. Efforts should be done to identify those patients.

Midostaurin in combination with intensive chemotherapy is safe and associated with improved remission rates and higher transplantation rates in first remission-a multi-center historical control study.

The addition of midostaurin, a FLT3-inhibitor, to intensive chemotherapy (IC) was previously shown to improve outcome of younger patients with FLT3-mutated AML. The toxicity and efficacy of adding midostaurin to IC in patients not originally included in the RATIFY study or with intensified daunorubicin dosing are unknown. We conducted a retrospective, multi-center, historical-control study to characterize the safety and efficacy of adding midostaurin to IC in a "real-world" setting. Sixty-nine adult patients were included in the analysis (midostaurin n = 34, historical controls n = 35) with a mean follow-up of 18.4 (± 15) months. Median age of patients was 60 (range 26-82) years; 32% and 20% of patients were > 65 and 70 years, respectively. No differences in baseline characteristics were noted between the groups. Midostaurin was administered with 90 mg/m2 daunorubicin in 29% of patients; One-third of patients experienced dose reductions/interruptions during midostaurin therapy. Overall toxicity was comparable between the midostaurin and control groups.CR/CRi rates were higher in patients treated with midostaurin compared with controls (80% vs. 57%, p = 0.047) and significantly more patients in the midostaurin group were transplanted in first remission (95% vs. 68%, p = 0.04).Median OS and DFS were higher in the midostaurin vs. control group (not reached vs. 11 months (p = 0.085) and 13 vs. 6 months (p = 0.09), respectively). In our analysis, midostaurin was not associated with increased toxicity including in older patients, in those with secondary AML or when administered with intensified daunorubicin dosage. Higher remission rates in the midostaurin group and increased transplantation rates in first CR were associated with a trend towards better outcomes.

Characteristics and outcomes of young adults with Philadelphia-negative myeloproliferative neoplasms.

OBJECTIVE: Approximately 10% of Philadelphia (Ph)-negative myeloproliferative neoplasms (NPM) are diagnosed at young adulthood. We aim to define the features of this group. METHODS: A multicenter retrospective study, including patients 18-45 years of age, diagnosed with Ph-negative MPN between 1985 and 2017. RESULTS: One hundred nine patients were included, 37 with polycythemia vera (34%), 54 with essential thrombocytosis (50%), 15 with primary myelofibrosis (PMF) (14%), and 3 with MPN unclassifiable (3%). Median age was 33 years and 62 (57%) were females. During a median follow-up of 8 years, 39 patients (37%) had at least one thrombotic event. 30/39 of events were venous (77%), 23/30 of which were splanchnic (77%). In 14/39 (36%), thrombosis preceded MPN diagnosis. In a multivariable analysis, only splenomegaly predicted for thrombosis (HR 5.6, CI: 1.4-22). The 10-year risk for secondary myelofibrosis was similar for ET and PV (0.13 vs 0.19, P = 0.51). The 10-year risk for leukemic transformation or mortality was significantly higher for PMF (0.3, P = 0.04). CONCLUSIONS: The risks of mortality and of progression to MF/leukemia in young adults are similar to older population. Thrombotic events are frequently a presenting sign with a high incidence of venous, in particular splanchnic, events.

Immune Mediated Cerebellar Ataxia: An Unknown Manifestation of Graft-versus-Host Disease.

Neurologic complications of allogeneic hematopoietic cell transplantation (allo-HCT) include infections, cerebrovascular events, therapy-induced neurotoxicity, recurrent malignancies, and neurologic manifestations of graft-versus-host disease (GVHD). Anti-glutamic acid decarboxylase (GAD) antibody-associated cerebellar ataxia is a well-established disorder of autoimmune origin, but there are no reports in the literature of its occurrence following allo-HCT. We describe a middle-aged woman with chronic GVHD after allo-HCT who presented with a rapidly progressive cerebellar syndrome. Thorough investigation revealed only cerebellar atrophy on brain imaging and positive anti-GAD65 antibodies in serum and cerebrospinal fluid suggesting the diagnosis of anti-GAD antibody-associated cerebellar ataxia. Despite prompt treatment with high-dose corticosteroids, intravenous immunoglobulins, and rituximab, the patient's condition rapidly deteriorated, and she died 4 months later. This case suggests that anti-GAD antibody-associated cerebellar ataxia may be a rare manifestation of chronic GVHD.

Indications for genetic testing leading to termination of pregnancy.

PURPOSE: In this study, we aimed to assess the distribution of genetic abnormalities leading to termination of pregnancy and its fluctuation during the past 8 years in light of those technical advances. METHODS: Our cohort consisted of all pregnant women who underwent termination of pregnancy because of genetic aberrations in their fetuses from January 2010 through April 2018 in our medical center. The information that was gathered included: maternal age, results of the nuchal scan, results of the first- and second-trimester biochemical screening, ultrasonographic findings, reasons for conducting a genetic evaluation, gestational age at which termination of pregnancy was carried out, and the type of genetic aberration. RESULTS: 816 women underwent termination of pregnancy at our institution due to genetic aberrations, most of them because of positive biochemical screening (n = 297, 36%) or because of maternal anxiety (n = 283, 35%). Findings in chromosomal microarray led to termination of pregnancy in 100 women (100/816, 12%). Chromosomal microarray had been performed due to maternal choice and not because of accepted medical indications among most of the women who underwent termination of pregnancy due to findings on chromosomal microarray (69/100, 69%). CONCLUSION: Performing chromosomal microarray on a structurally normal fetus and identifying abnormal copy number variants may give the parents enough information for deciding on the further course of the pregnancy.

The Effects of Proteasome Inhibitors on Telomerase Activity and Regulation in Multiple Myeloma Cells.

The importance of telomerase, the enzyme that maintains telomere length, has been reported in many malignancies in general and in multiple myeloma (MM) in particular. Proteasome inhibitors are clinically used to combat effectively MM. Since the mechanism of action of proteasome inhibitors has not been fully described we sought to clarify its potential effect on telomerase activity (TA) in MM cells. Previously we showed that the first generation proteasome inhibitor bortezomib (Brt) inhibits TA in MM cells by both transcriptional and post-translational mechanisms and has a potential clinical significance. In the current study we focused around the anti- telomerase activity of the new generation of proteasome inhibitors, epoxomicin (EP) and MG-132 in order to clarify whether telomerase inhibition represents a class effect. We have exposed MM cell lines, ARP-1, CAG, RPMI 8226 and U266 to EP or MG and the following parameters were assessed: viability; TA, hTERT expression, the binding of hTERT (human telomerase reverse transcriptase) transcription factors and post-translational modifications. Epoxomicin and MG-132 differentially downregulated the proliferation and TA in all MM cell lines. The downregulation of TA and the expression of hTERT were faster in CAG than in ARP-1 cells. Epoxomicin was more potent than MG-132 and therefore further mechanistic studies were performed using this compound. The inhibition of TA was mainly transcriptionally regulated. The binding of three positive regulator transcription factors: SP1, c-Myc and NF-κB to the hTERT promoter was decreased by EP in CAG cells as well as their total cellular expression. In ARP-1 cells the SP1 and c-MYC binding and protein levels were similarly affected by EP while NF-κB was not affected. Interestingly, the transcription factor WT-1 (Wilms' tumor-1) exhibited an increased binding to the hTERT promoter while its total cellular amount remained unchanged. Our results combined with our previous study of bortezomib define telomerase as a general target for proteasome inhibitors. The inhibitory effect of TA is exerted by several regulatory levels, transcriptional and post translational. SP1, C-Myc and NF-κB were involved in mediating these effects. A novel finding of this study is the role of WT-1 in the regulation of telomerase which appears as a negative regulator of hTERT expression. The results of this study may contribute to future development of telomerase inhibition as a therapeutic modality in MM.

The absolute percent deviation of IGHV mutation rather than a 98% cut-off predicts survival of chronic lymphocytic leukaemia patients treated with fludarabine, cyclophosphamide and rituximab.

The degree of somatic hypermutation, determined as percent deviation of immunoglobulin heavy chain gene variable region sequence from the germline (IGHV%), is an important prognostic factor in chronic lymphocytic leukaemia (CLL). Currently, a cut-off of 2% deviation or 98% sequence identity to germline in IGHV sequence is routinely used to dichotomize CLL patients into mutated and unmutated groups. Because dissimilar IGHV% cut-offs of 1-5% were identified in different studies, we wondered whether no cut-off should be applied and IGHV% treated as a continuous variable. We analysed the significance of IGHV% in 203 CLL patients enrolled on the original frontline fludarabine, cyclophosphamide and rituximab (FCR) trial with a median of 10 years follow-up. Using the Cox Proportional Hazard model, IGHV% was identified as a continuous variable that is significantly associated with progression-free (PFS) and overall survival (OS) (P < 0·001). Furthermore, we validated this finding in 323 patients treated with FCR off-protocol and in the total cohort (n = 535). Multivariate analysis revealed a continuous trend. Higher IGHV% levels were incrementally associated with favorable PFS and OS in both FCR-treated cohorts (P < 0·001, both cohorts). Taken together, our data suggest that IGHV% is a continuous variable in CLL patients treated with FCR.

At High Levels, Constitutively Activated STAT3 Induces Apoptosis of Chronic Lymphocytic Leukemia Cells.

In chronic lymphocytic leukemia (CLL), the increment in PBLs is slower than the expected increment calculated from the cells' proliferation rate, suggesting that cellular proliferation and apoptosis are concurrent. Exploring this phenomenon, we found overexpression of caspase-3, higher cleaved poly (ADP-ribose) polymerase levels (p < 0.007), and a higher apoptosis rate in cells from patients with high counts compared with cells from patients with low counts. Although we previously found that STAT3 protects CLL cells from apoptosis, STAT3 levels were significantly higher in cells from patients with high counts than in cells from patients with low counts. Furthermore, overexpression of STAT3 did not protect the cells. Rather, it upregulated caspase-3 and induced apoptosis. Remarkably, putative STAT3 binding sites were identified in the caspase-3 promoter, and a luciferase assay, chromatin immunoprecipitation, and an EMSA revealed that STAT3 activated caspase-3 However, caspase-3 levels increased only when STAT3 levels were sufficiently high. Using chromatin immunoprecipitation and EMSA, we found that STAT3 binds with low affinity to the caspase-3 promoter, suggesting that at high levels, STAT3 activates proapoptotic mechanisms and induces apoptosis in CLL cells.

Why Is the Immunoglobulin Heavy Chain Gene Mutation Status a Prognostic Indicator in Chronic Lymphocytic Leukemia?

The immunoglobulin heavy chain gene (IgHV) mutation status correlates with the clinical outcome of patients with chronic lymphocytic leukemia (CLL) treated with chemoimmunotherapy. Why the survival rate of patients with unmutated IgHV is worse than that of patients with mutated IgHV is unknown. CLL cells with unmutated IgHV were thought to originate from naïve B lymphocytes, whereas CLL cells with mutated IgHV were thought to arise from B cells that have undergone somatic hypermutation (SHM). Cell surface protein expression profile and gene expression studies showing that all CLL cells, regardless of their IgHV mutation status, are of postgerminal center origin, negated this hypothesis. We hereby propose that all CLL cells undergo SHM and their proliferation rate determines their IgHV mutation status. DNA breaks, accumulated during SHM, are restored by various DNA repair mechanisms. In rapidly dividing cells DNA breaks are repaired by the efficient high-fidelity homology-directed DNA repair apparatus, whereas in slowly dividing cells they are repaired by the inefficient low-fidelity nonhomology end-joining repair mechanism. Accordingly, a low IgHV mutation rate is found in rapidly dividing cells whereas a high mutation rate is typically found in slowly dividing cells. Thus, the proliferation rate of CLL cells determines the IgHV mutation status and patients' clinical outcome.