Search

The presence of a monoclonal protein detected by serum immunofixation electrophoresis (sIFE) has been reported as an adverse prognostic factor in chronic lymphocytic leukemia (CLL). However, the genetic underpinning of this finding has not been studied. We retrospectively studied 97 CLL patients with simultaneous information on sIFE and genetic alterations detected by next-generation sequencing. sIFE was positive in 49 patients. The most common isotypes were IgG κ (27%) and bi/triclonal (25%). A +sIFE was associated with a higher number of mutated genes [median 2 (range 0–3) vs. 0 (range 0–2), p = 0.006], and a higher frequency of unmutated IGHV status (60 vs. 29%, p = 0.004). An IgM monoclonal protein was associated with TP53 mutations (36% in IgM +sIFE vs. 12% in non-IgM +sIFE or –sIFE, p = 0.04), and bi/triclonal proteins with NOTCH1 mutations (33% in bi/triclonal vs. 9% in monoclonal +sIFE or –sIFE, p = 0.04). These data suggest an association between a +sIFE and a higher mutational burden, and some monoclonal isotypes with specific mutations. [ABSTRACT FROM AUTHOR]

Serum soluble CD23 (sCD23) levels have been acknowledged as a prognostic factor in patients with chronic lymphocytic leukemia (CLL), but their potential relevance has not been analyzed in recent times. We retrospectively studied 338 CLL, small lymphocytic lymphoma, or CLL‐type monoclonal B‐cell lymphocytosis patients from a single institution, with available sCD23 levels at diagnosis. Baseline features and outcomes were compared between patients with sCD23 ≤/>1000 UI/L. The 140 patients (41%) who had sCD23 > 1000 UI/L showed adverse‐risk clinical and biological characteristics. High sCD23 levels were predictive of a shorter time to first treatment (5‐year probability of requiring treatment: 60 vs. 20%, p < 0.0001; hazard ratio (HR) = 1.72, p = 0.003 in a multivariable model also including the CLL International Prognostic Index and the absolute lymphocyte count), and a poorer 5‐year overall survival (70 vs. 82%, p = 0.0009). These data suggest the potential of sCD23 to predict treatment‐free survival and to shed light on mechanisms of activity and resistance to CD23‐directed therapies. [ABSTRACT FROM AUTHOR]

CART19 cells are emerging as an alternative therapy for patients with chronic lymphocytic leukemia (CLL). Here we report the outcome of nine consecutive patients with CLL treated with ARI-0001 CART19 cells, six of them with Richter's transformation (RT). One patient with RT never received therapy. The cytokine release syndrome rate was 87.5% (12.5% grade ≥3). Neurotoxicity was not observed in any patient. All patients experienced absolute B-cell aplasia, and seven (87.5%) responded to therapy. With a median follow-up of 5.6 months, two patients with RT experienced a CD19-negative relapse. In conclusion, ARI-0001 cell therapy was feasible, safe, and effective in patients with high-risk CLL or RT. [ABSTRACT FROM AUTHOR]

The Bruton's tyrosine kinase (BTK) inhibitor ibrutinib has been shown to be highly effective in patients with chronic lymphocytic leukemia (CLL) and is approved for CLL treatment. Unfortunately, resistance and intolerance to ibrutinib has been observed in several studies, opening the door for more specific BTK inhibitors. CC‐292 (spebrutinib) is a BTK inhibitor with increased specificity for BTK and less inhibition of other kinases. Our in vitro studies showed that CC‐292 potently inhibited B‐cell receptor signaling, activation, proliferation and chemotaxis of CLL cells. In in vivo studies using the adoptive transfer TCL1 mouse model of CLL, CC‐292 reduced tumor load and normalized tumor‐associated expansion of T cells and monocytes, while not affecting T cell function. Importantly, the combination of CC‐292 and bendamustine impaired CLL cell proliferation in vivo and enhanced the control of CLL progression. Our results demonstrate that CC‐292 is a specific BTK inhibitor with promising performance in combination with bendamustine in CLL. Further clinical trials are warranted to investigate the therapeutic efficacy of this combination regimen. What's new? B‐cell receptor (BCR) signaling plays a pivotal role in chronic lymphocytic leukemia (CLL). BTK inhibitor ibrutinib has been shown to be highly effective in patients, but resistance and intolerance have also been observed. Here, the authors demonstrate that the more specific CC‐292 disrupts BCR signaling and inhibits tumor cell activation, proliferation, and chemotaxis in vitro. In mice, CC‐292 reduces tumor load and normalizes tumor‐associated expansion of T cells and monocytes while not affecting T cell function. Combination of CC‐292 and bendamustine impairs CLL cell proliferation and normalizes immune cell composition, which overcomes microenvironment‐mediated chemoresistance and enhances control of CLL progression. [ABSTRACT FROM AUTHOR]

We investigated CD49d (also termed ITGA4) expression and its biological and clinical correlations in 415 patients with chronic lymphocytic leukaemia. CD49d expression was stable over the course of the disease. A high expression of CD49d (>30%) was found in 142/415 (34%) patients and was associated with progressive disease (advanced clinical stage, high serum lactate dehydrogenase or β2-microglobulin levels; all p < 0·05) and aggressive disease biology (increased ZAP70 or CD38, unmutated IGHV, trisomy 12, mutations of NOTCH1 and SF3B1; all P < 0·05). A higher CD49d expression was also associated with a lower blood lymphocyte count and a higher number of lymphoid areas involved by the disease. Patients with high CD49d expression were treated more frequently (55% vs. 27%; P < 0·001) and earlier (median time to treatment [TTT] 65·4 months vs. not reached; P < 0·001) than those with low CD49d expression. However, no significant differences in response rates were observed. In the subgroup of patients with mutated IGHV, high CD49d expression was predictive of a shorter TTT while other markers, such as ZAP70 and CD38, were not. In conclusion, in this study CD49d expression correlated with high-risk CLL biomarkers and proved to be useful for separating patients with mutated IGHV into two different prognostic groups. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukaemia (CLL) is a frequent disease in which the genetic alterations determining the clinicobiological behaviour are not fully understood. Here we describe a comprehensive evaluation of the genomic landscape of 452 CLL cases and 54 patients with monoclonal B-lymphocytosis, a precursor disorder. We extend the number of CLL driver alterations, including changes in ZNF292, ZMYM3, ARID1A and PTPN11. We also identify novel recurrent mutations in non-coding regions, including the 3′ region of NOTCH1, which cause aberrant splicing events, increase NOTCH1 activity and result in a more aggressive disease. In addition, mutations in an enhancer located on chromosome 9p13 result in reduced expression of the B-cell-specific transcription factor PAX5. The accumulative number of driver alterations (0 to ≥4) discriminated between patients with differences in clinical behaviour. This study provides an integrated portrait of the CLL genomic landscape, identifies new recurrent driver mutations of the disease, and suggests clinical interventions that may improve the management of this neoplasia. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukemia (CLL) is the most frequent leukemia in adults. We have analyzed exome sequencing data from 127 individuals with CLL and Sanger sequencing data from 214 additional affected individuals, identifying recurrent somatic mutations in POT1 (encoding protection of telomeres 1) in 3.5% of the cases, with the frequency reaching 9% when only individuals without IGHV@ mutations were considered. POT1 encodes a component of the shelterin complex and is the first member of this telomeric structure found to be mutated in human cancer. Somatic mutation of POT1 primarily occurs in gene regions encoding the two oligonucleotide-/oligosaccharide-binding (OB) folds and affects key residues required to bind telomeric DNA. POT1-mutated CLL cells have numerous telomeric and chromosomal abnormalities that suggest that POT1 mutations favor the acquisition of the malignant features of CLL cells. The identification of POT1 as a new frequently mutated gene in CLL may facilitate novel approaches for the clinical management of this disease. [ABSTRACT FROM AUTHOR]

Summary The analysis of chromosomal abnormalities provides significant prognostic information in patients with chronic lymphocytic leukaemia (CLL), a disease with a highly heterogeneous clinical course. Chromosomal abnormalities commonly found are trisomy 12, del(13)(q14), del(11)(q22-23), del(17)(p13) and del(6)(q21). Translocations are present in some patients and affect regions recurrently involved in CLL. This report describes the clinical and pathological characteristics of four CLL patients showing a new recurrent chromosomal abnormality dic(8;17)(p11;p11), that implied loss of the TP53 gene in all cases. In addition, TP53 gene was mutated in three out of four patients. Mechanically, Low Copy Repeats (LCR) in 17p12 and 8p11 may explain the origin of the translocation by non-allelic homologous recombination (NAHR). Isolated dic(8;17)(p11;p11) in patients with mutated IGHV genes status may not have the same prognostic impact as other mutations or deletions affecting the TP53 gene. Larger series are needed to better evaluate the clinical impact of this chromosomal aberration during the course of the disease. [ABSTRACT FROM AUTHOR]

Here we perform whole-exome sequencing of samples from 105 individuals with chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults in Western countries. We found 1,246 somatic mutations potentially affecting gene function and identified 78 genes with predicted functional alterations in more than one tumor sample. Among these genes, SF3B1, encoding a subunit of the spliceosomal U2 small nuclear ribonucleoprotein (snRNP), is somatically mutated in 9.7% of affected individuals. Further analysis in 279 individuals with CLL showed that SF3B1 mutations were associated with faster disease progression and poor overall survival. This work provides the first comprehensive catalog of somatic mutations in CLL with relevant clinical correlates and defines a large set of new genes that may drive the development of this common form of leukemia. The results reinforce the idea that targeting several well-known genetic pathways, including mRNA splicing, could be useful in the treatment of CLL and other malignancies. [ABSTRACT FROM AUTHOR]

Chronic lymphocytic leukaemia (CLL), the most frequent leukaemia in adults in Western countries, is a heterogeneous disease with variable clinical presentation and evolution. Two major molecular subtypes can be distinguished, characterized respectively by a high or low number of somatic hypermutations in the variable region of immunoglobulin genes. The molecular changes leading to the pathogenesis of the disease are still poorly understood. Here we performed whole-genome sequencing of four cases of CLL and identified 46 somatic mutations that potentially affect gene function. Further analysis of these mutations in 363 patients with CLL identified four genes that are recurrently mutated: notch 1 (NOTCH1), exportin 1 (XPO1), myeloid differentiation primary response gene 88 (MYD88) and kelch-like 6 (KLHL6). Mutations in MYD88 and KLHL6 are predominant in cases of CLL with mutated immunoglobulin genes, whereas NOTCH1 and XPO1 mutations are mainly detected in patients with unmutated immunoglobulins. The patterns of somatic mutation, supported by functional and clinical analyses, strongly indicate that the recurrent NOTCH1, MYD88 and XPO1 mutations are oncogenic changes that contribute to the clinical evolution of the disease. To our knowledge, this is the first comprehensive analysis of CLL combining whole-genome sequencing with clinical characteristics and clinical outcomes. It highlights the usefulness of this approach for the identification of clinically relevant mutations in cancer. [ABSTRACT FROM AUTHOR]

Summary. We evaluated the efficacy and toxicity of fludarabine combined with cyclophosphamide and mitoxantrone (FCM) in patients with relapsed or resistant chronic lymphocytic leukaemia (CLL). In total, 37 patients with recurrent or resistant CLL received FCM: fludarabine 25 mg/m2 intravenously (IV), d 1–3; cyclophosphamide 200 mg/m2 IV, d 1–3; and mitoxantrone 6 mg/m2 IV, d 1, at 4-week intervals for up to six courses. Moreover, 23 patients received FCM with cyclophosphamide 600 mg/m2 i.v. and mitoxantrone 8 mg/m2 i.v. on d 1. In addition to clinical methods, response was assessed using cytofluorometric and molecular techniques. ‘In vitro ’ sensitivity to the FCM regimen was also analysed in 20 samples. The median number of courses given was 3 (range: 1–6). Overall, 30 patients (50%) achieved complete response (CR), including 10 cases of negative minimal residual disease (MRD(–)) (17%), and 17 (28%) partial response (PR). The median duration of response was 19 months. ‘In vitro ’ sensitivity also correlated with CR achievement (P = 0·04). Main toxicity consisted of neutropenia, infections (8% of courses), and nausea and vomiting. The treatment-related mortality was 5%. FCM did not hamper stem cell harvesting in patients who were candidates for autologous stem cell transplantation. FCM induced a high CR rate, including an important number of MRD(–), in patients with previously treated CLL. [ABSTRACT FROM AUTHOR]

Genomic studies have recently identified RPS 15 as a new driver gene in aggressive and chemorefractory cases of chronic lymphocytic leukemia (CLL). RPS15 encodes a ribosomal protein whose conserved C-terminaf domain extends into the decoding center of the ribosome. We demonstrate that mutations in highly conserved residues of this domain affect protein stability, by increasing its ubiquitin-mediated degradation, and cell-proliferation rates. On the other hand, we show that mutated RPS15 can be loaded into the ribosomes, directly impacting on global protein synthesis and/or translational fidelity in a mutation-specific manner. Quantitative mass spectrometry analyses suggest that RPS15 variants may induce additional alterations in the translational machinery, as well as a metabolic shift at the proteome level in HEK293T and MEC-1 cells. These results indicate that CLL-related RPS15 mutations might act following patterns known for other ribosomal diseases, likely switching from a hypo- to a hyperproliferative phenotype driven by mutated ribosomes. In this scenario, loss of translational fidelity causing altered cell proteostasis can be proposed as a new molecular mechanism involved in CLL pathobiology. [ABSTRACT FROM AUTHOR]

Genomic studies have revealed the complex clonal heterogeneity of chronic lymphocytic leukemia (CLL). The acquisition and selection of genomic aberrations may be critical to understanding the progression of this disease. In this study, we have extensively characterized the mutational status of TP53, SF3B1, BIRC3, NOTCH1, and ATM in 406 untreated CLL cases by ultra-deep next-generation sequencing, which detected subclonal mutations down to 0.3% allele frequency. Clonal dynamics were examined in longitudinal samples of 48 CLL patients. We identified a high proportion of subclonal mutations, isolated or associated with clonal aberrations. TP53 mutations were present in 10.6% of patients (6.4% clonal, 4.2% subclonal), ATM mutations in 11.1% (7.8% clonal, 1.3% subclonal, 2% germ line mutations considered pathogenic), SF3B1 mutations in 12.6% (7.4% clonal, 5.2% subclonal), NOTCH1 mutations in 21.8% (14.2% clonal, 7.6% subclonal), and BIRC3 mutations in 4.2% (2% clonal, 2.2% subclonal). ATM mutations, clonal SF3B1, and both clonal and subclonal NOTCH1 mutations predicted for shorter time to first treatment irrespective of the immunoglobulin heavy-chain variable-region gene (IGHV) mutational status. Clonal and subclonal TP53 and clonal NOTCH1 mutations predicted for shorter overall survival together with the IGHV mutational status. Clonal evolution in longitudinal samples mainly occurred in cases with mutations in the initial samples and was observed not only after chemotherapy but also in untreated patients. These findings suggest that the characterization of the subclonal architecture and its dynamics in the evolution of the disease may be relevant for the management of CLL patients. [ABSTRACT FROM AUTHOR]

Abstract: We evaluated the efficacy and toxicity of retreatment with purine analogs (PA) in 62 patients with relapsed chronic lymphocytic leukemia. Median OS and PFS after retreatment were 60 and 26 months, respectively. By multivariate analysis, minimal residual disease status, ZAP-70 expression and age had independent predictive power in terms of OS. Toxicity was mainly neutropenia (21%) and infections (39%). Second malignancies were observed in 10 (16%) patients. Our results outline that retreatment with PA is remarkably effective in patients with relapsed CLL, but with a significant toxicity. [Copyright &y& Elsevier]

Background: The mutational status of immunoglobulin heavy-chain variable-region (IgV) genes in the leukemic cells of chronic lymphocytic leukemia (CLL) is an important prognostic factor in the disease. We investigated whether the expression of ZAP-70 by CLL cells correlated with the IgV mutational status, disease progression, and survival. Methods: The expression of ZAP-70 was analyzed in T-cell and B-cell lines and in peripheral-blood samples from 56 patients with CLL with the use of flow cytometry, Western blotting, and immunohistochemistry. The results were correlated with the IgV mutational status and clinical outcome. Results: ZAP-70 was detected by flow-cytometric analysis in cells of T-cell lineage and in leukemic cells from 32 of 56 patients with CLL. In all patients in whom at least 20 percent of the leukemic cells were positive for ZAP-70, IgV was unmutated, whereas IgV mutations were found in 21 of 24 patients in whom less than 20 percent of the leukemic cells were positive for ZAP-70 (P<0.001). Concordant results were obtained when ZAP-70 expression was assessed by immunohistochemistry or Western blotting. The level of ZAP-70 expression did not change over time (median, 37 months) in sequential samples from 30 patients with CLL. Patients with Binet stage A CLL who had at least 20 percent ZAP-70–positive leukemic cells had more rapid progression and poorer survival than those with less than 20 percent ZAP-70–positive cells. Conclusions: Among patients with CLL, expression of ZAP-70, as detected by flow-cytometric analysis, correlated with IgV mutational status, disease progression, and survival. N Engl J Med 2003;348:1764-75. [ABSTRACT FROM AUTHOR]

A letter to the editor is presented in response to the article "Prognostic relevance of MYD88 mutations in CLL: the jury is still out" by P. Baliakas and colleagues in the previous issue.