TP53 aberrations in chronic lymphocytic leukemia: an overview of the clinical implications of improved diagnostics

Acute Erythroid Leukemia: From Molecular Biology to Clinical Outcomes

Acute Erythroid Leukemia (AEL) is a rare and aggressive subtype of Acute Myeloid Leukemia (AML). In 2022, the World Health Organization (WHO) defined AEL as a biopsy with ≥30% proerythroblasts and erythroid precursors that account for ≥80% of cellularity. The International Consensus Classification refers to this neoplasm as "AML with mutated TP53". Classification entails ≥20% blasts in blood or bone marrow biopsy and a somatic TP53 mutation (VAF > 10%). This type of leukemia is typically associated with biallelic TP53 mutations and a complex karyotype, specifically 5q and 7q deletions. Transgenic mouse models have implicated several molecules in the pathogenesis of AEL, including transcriptional master regulator GATA1 (involved in erythroid differentiation), master oncogenes, and CDX4. Recent studies have also characterized AEL by epigenetic regulator mutations and transcriptome subgroups. AEL patients have overall poor clinical outcomes, mostly related to their poor response to the standard therapies, which include hypomethylating agents and intensive chemotherapy. Allogeneic bone marrow transplantation (AlloBMT) is the only potentially curative approach but requires deep remission, which is very challenging for these patients. Age, AlloBMT, and a history of antecedent myeloid neoplasms further affect the outcomes of these patients. In this review, we will summarize the diagnostic criteria of AEL, review the current insights into the biology of AEL, and describe the treatment options and outcomes of patients with this disease.

Outcomes with ibrutinib in patients with chronic lymphocytic leukaemia: Results from the German multicentre REALITY study

OBJECTIVES

To assess treatment adherence, effectiveness and safety outcomes of patients with chronic lymphocytic leukaemia (CLL) receiving ibrutinib in a real-world setting.

METHODS

Patients enrolled in REALITY were ≥18 years with a confirmed diagnosis of CLL and were receiving ibrutinib as a first-line (1L), 2L or ≥3L therapy. Treatment retention, adherence, progression-free survival (PFS), overall survival (OS) and time to next therapy were assessed at 1 and 2 years overall, by typology and by cytogenetic subgroups. PFS and OS were analysed using Kaplan-Meier methods.

RESULTS

Exactly 302 patients were enrolled across 57 sites in Germany, from January 2017 to July 2021. One-year retention rates were 69.9% overall (primary endpoint), 77.9% for 1L patients, and 77.6%/78.8% for high-risk patients with del17p/TP53. At 2 years, PFS/OS rates were 77.8%/90.7% overall (1L, 82.7%/90.4%), and were consistent across cytogenetic subgroups. PFS rates were higher for 1L versus ≥3L patients. Patients with the low-acceptance/low-control typology at baseline were less likely to retain treatment at 1 year versus the high-acceptance/high-control typology. No new safety signals were observed.

CONCLUSIONS

The REALITY study provides further evidence of the effectiveness and safety of ibrutinib in patients with CLL in a real-world setting, particularly in earlier treatment lines.

Biologic and Clinical Characteristics of Isochromosome der(17)(q10)t(15;17) in Acute Promyelocytic Leukemia

INTRODUCTION

Acute promyelocytic leukemia (APL) is genetically characterized by the fusion of promyelocytic leukemia (PML) gene with retinoic acid receptor alpha (RARα) resulting from a t(15;17)(q24;q21) chromosomal translocation. An infrequent but recurrent finding in APL is the formation of an isochromosome of the derivative chromosome 17; ider(17)(q10)t(15;17) or ider(17q). This rearrangement in APL results in an additional copy of the PML-RARα fusion gene as well as loss of 17p/TP53. Due to the infrequent occurrence of the ider(17q), the prognostic impact of this genetic finding is not well known. Case Presentation(s): Here, we describe the clinical characteristics and outcomes of our case series of 5 patients with ider(17q) APL treated at the University of Maryland and Johns Hopkins University.

CONCLUSION

In our series, patients with APL with ider(17q) did not have a worse prognosis.

Genetic variability profiling of the p53 signaling pathway in chronic lymphocytic leukemia. Individual and combined analysis of TP53, MDM2 and NQO1 gene variants

TP53 gene disruption, including 17p13 deletion [del(17p)] and/or TP53 mutations, is a negative prognostic biomarker in chronic lymphocytic leukemia (CLL) associated with disease progression, treatment failure and shorter survival. Germline variants in p53 signaling pathway genes could also lead to p53 dysfunction, but their involvement in CLL has not been thoroughly evaluated. The aim of this study was to determine the association of TP53, MDM2 and NQO1 gene variability with clinical and genetic data of CLL patients. Individual genotype and haplotype data of CLL patients were compared with clinical prognostic factors, cytogenetic and molecular cytogenetic findings as well as IGHV and TP53 mutational status. The study included 116 CLL patients and 161 healthy blood donors. TP53 (rs1042522, rs59758982, rs1625895), NQO1 (rs1800566) and MDM2 (rs2279744, rs150550023) variants were genotyped using different PCR approaches. Analysis of genotype frequencies revealed no association with the risk of CLL. TP53 rs1042522, rs1625895 and MDM2 rs2279744 variants were significantly associated with abnormal karyotype and the presence of del(17p). Similarly, these two TP53 variants were associated with TP53 disruption. Moreover, TP53 C-A-nondel and G-A-del haplotypes (rs1042522-rs1625895-rs59758982) were associated with an increased likelihood of carrying del(17p) and TP53 disruptions. MDM2 T-nondel haplotype (rs2279744-rs150550023) was found to be a low risk factor for del(17p) (OR = 0.32; CI: 0.12-0.82; p = 0.02) and TP53 disruptions (OR = 0.41; CI: 0.18-0.95; p = 0.04). Our findings suggest that TP53 and MDM2 variants may modulate the risk to have chromosome alterations and TP53 disruptions, particularly del(17p). To our knowledge this is the first study of several germline variants in p53 pathway genes in Argentine patients with CLL.

Current Therapeutic Sequencing in Chronic Lymphocytic Leukemia

The treatment landscape of chronic lymphocytic leukemia (CLL), the most frequent leukemia in adults, is constantly changing. CLL patients can be divided into three risk categories, based on their IGHV mutational status and the occurrence of TP53 disruption and/or complex karyotype. For the first-line treatment of low- and intermediate-risk CLL, both the BCL2 inhibitor venetoclax plus obinutuzumab and the second generation BTK inhibitors (BTKi), namely acalabrutinib and zanubrutinib, are valuable and effective options. Conversely, venetoclax-based fixed duration therapies have not shown remarkable results in high-risk CLL patients, while continuous treatment with acalabrutinib and zanubrutinib displayed favorable outcomes, similar to those obtained in TP53 wild-type patients. The development of acquired resistance to pathway inhibitors is still a clinical challenge, and the optimal treatment sequencing of relapsed/refractory CLL is not completely established. Covalent BTKi-refractory patients should be treated with venetoclax plus rituximab, whereas venetoclax-refractory CLL may be treated with second generation BTKi in the case of early relapse, while venetoclax plus rituximab might be used if late relapse has occurred. On these grounds, here we provide an overview of the current state-of-the-art therapeutic algorithms for treatment-naïve patients, as well as for relapsed/refractory disease.

CD20+ T cells in monoclonal B cell lymphocytosis and chronic lymphocytic leukemia: frequency, phenotype and association with disease progression

Introduction

In monoclonal B cell lymphocytosis (MBL) and chronic lymphocytic leukemia (CLL), the expansion of malignant B cells disrupts the normal homeostasis and interactions between B cells and T cells, leading to immune dysregulation. CD20+ T cells are a subpopulation of T cells that appear to be involved in autoimmune diseases and cancer.

Methods

Here, we quantified and phenotypically characterized CD20+ T cells from MBL subjects and CLL patients using flow cytometry and correlated our findings with the B-cell receptor mutational status and other features of the disease.

Results and discussion

CD20+ T cells were more represented within the CD8+ T cell compartment and they showed a predominant memory Tc1 phenotype. CD20+ T cells were less represented in MBL and CLL patients vs healthy controls, particularly among those with unmutated IGVH gene. The expansion of malignant B cells was accompanied by phenotypic and functional changes in CD20+ T cells, including an increase in follicular helper CD4+ CD20+ T cells and CD20+ Tc1 cells, in addition to the expansion of the TCR Vβ 5.1 in CD4+ CD20+ T cells in CLL.

An unappreciated cell survival-independent role for BAFF initiating chronic lymphocytic leukemia

Background

Chronic Lymphocytic Leukemia (CLL) is characterized by the expansion of CD19+ CD5+ B cells but its origin remains debated. Mutated CLL may originate from post-germinal center B cells and unmutated CLL from CD5+ mature B cell precursors. Irrespective of precursor types, events initiating CLL remain unknown. The cytokines BAFF and APRIL each play a significant role in CLL cell survival and accumulation, but their involvement in disease initiation remains unclear.

Methods

We generated novel CLL models lacking BAFF or APRIL. In vivo experiments were conducted to explore the impact of BAFF or APRIL loss on leukemia initiation, progression, and dissemination. Additionally, RNA-seq and quantitative real-time PCR were performed to unveil the transcriptomic signature influenced by BAFF in CLL. The direct role of BAFF in controlling the expression of tumor-promoting genes was further assessed in patient-derived primary CLL cells ex-vivo.

Results

Our findings demonstrate a crucial role for BAFF, but not APRIL, in the initiation and dissemination of CLL cells. In the absence of BAFF or its receptor BAFF-R, the TCL1 transgene only increases CLL cell numbers in the peritoneal cavity, without dissemination into the periphery. While BAFF binding to BAFF-R is dispensable for peritoneal CLL cell survival, it is necessary to activate a tumor-promoting gene program, potentially linked to CLL initiation and progression. This direct role of BAFF in controlling the expression of tumor-promoting genes was confirmed in patient-derived primary CLL cells ex-vivo.

Conclusions

Our study, involving both mouse and human CLL cells, suggests that BAFF might initiate CLL through mechanisms independent of cell survival. Combining current CLL therapies with BAFF inhibition could offer a dual benefit by reducing peripheral tumor burden and suppressing transformed CLL cell output.

MicroRNAs: Potential prognostic and theranostic biomarkers in chronic lymphocytic leukemia

Small noncoding ribonucleic acids called microRNAs coordinate numerous critical physiological and biological processes such as cell division, proliferation, and death. These regulatory molecules interfere with the function of many genes by binding the 3'-UTR region of target mRNAs to inhibit their translation or even degrade them. Given that a large proportion of miRNAs behave as either tumor suppressors or oncogenes, any genetic or epigenetic aberration changeing their structure and/or function could initiate tumor formation and development. An example of such cancers is chronic lymphocytic leukemia (CLL), the most prevalent adult leukemia in Western nations, which is caused by unregulated growth and buildup of defective cells in the peripheral blood and lymphoid organs. Genetic alterations at cellular and molecular levels play an important role in the occurrence and development of CLL. In this vein, it was noted that the development of this disease is noticeably affected by changes in the expression and function of miRNAs. Many studies on miRNAs have shown that these molecules are pivotal in the prognosis of different cancers, including CLL, and their epigenetic alterations (e.g., methylation) can predict disease progression and response to treatment. Furthermore, miRNAs are involved in the development of drug resistance in CLL, and targeting these molecules can be considered a new therapeutic approach for the treatment of this disease. MiRNA screening can offer important information on the etiology and development of CLL. Considering the importance of miRNAs in gene expression regulation, their application in the diagnosis, prognosis, and treatment of CLL is reviewed in this paper.

Chronic Lymphocytic Leukemia IGHV Somatic Hypermutation Detection by Targeted Capture Next-Generation Sequencing

BACKGROUND

Somatic hypermutation (SHM) status of the immunoglobulin heavy variable (IGHV) gene plays a crucial role in determining the prognosis and treatment of patients with chronic lymphocytic leukemia (CLL). A common approach for determining SHM status is multiplex polymerase chain reaction and Sanger sequencing of the immunoglobin heavy locus; however, this technique is low throughput, is vulnerable to failure, and does not allow multiplexing with other diagnostic assays.

METHODS

Here we designed and validated a DNA targeted capture approach to detect immunoglobulin heavy variable somatic hypermutation (IGHV SHM) status as a submodule of a larger next-generation sequencing (NGS) panel that also includes probes for ATM, BIRC3, CHD2, KLHL6, MYD88, NOTCH1, NOTCH2, POT1, SF3B1, TP53, and XPO1. The assay takes as input FASTQ files and outputs a report containing IGHV SHM status and V allele usage following European Research Initiative on CLL guidelines.

RESULTS

We validated the approach on 35 CLL patient samples, 34 of which were characterized using Sanger sequencing. The NGS panel identified the IGHV SHM status of 34 of 35 CLL patients. We showed 100% sensitivity and specificity among the 33 CLL samples with both NGS and Sanger sequencing calls. Furthermore, we demonstrated that this panel can be combined with additional targeted capture panels to detect prognostically important CLL single nucleotide variants, insertions/deletions, and copy number variants (TP53 copy number loss).

CONCLUSIONS

A targeted capture approach to IGHV SHM detection can be integrated into broader sequencing panels, allowing broad CLL prognostication in a single molecular assay.

Targeting TP53 disruption in chronic lymphocytic leukemia: Current strategies and future directions

In the modern era of Chronic Lymphocytic Leukemia (CLL) targeted therapy, the loss of p53 function due to genetic abnormalities remains a significant challenge. This is because even targeted agents, which are currently the mainstay of treatment for CLL, do not directly target p53 or restore its disrupted pathway. Consequently, resistance to therapy and unfavorable clinical outcomes often accompany these p53-related abnormalities. An essential goal of future clinical research should be to address the ostensibly "undruggable" p53 pathway. Currently, multiple therapeutic approaches are being explored to tackle TP53 dysfunction and improve outcomes in high-risk CLL. These approaches include the use of oncoprotein murine double minute 2 inhibitors, small-molecule p53 reactivators, exportin 1 (XPO1) inhibitors, and ataxia-telangiectasia mutated and Rad3-related (ATR) inhibitors. Combinations of these p53-targeting strategies, along with established novel therapies such as B-cell receptor or B-cell lymphoma-2 (BCL-2) inhibitors, may shape the future of therapeutic trials in this challenging-to-treat disease.

Cost Effectiveness of Molecular Diagnostic Testing Algorithms for the Treatment Selection of Frontline Ibrutinib for Patients with Chronic Lymphocytic Leukemia in Australia

BACKGROUND

Clinical indications for ibrutinib reimbursement in Australia should consider the inclusion of patients with chronic lymphocytic leukemia (CLL) harboring prognostically unfavorable TP53/IGHV genomic aberrations. This study assessed the cost effectiveness of five first-line treatment strategies in CLL for young (aged ≤ 65 years), fit patients without significant comorbidities: (1) no testing (fludarabine, cyclophosphamide and rituximab [FCR] for all), (2) test for del(17p) only, (3) test for TP53 gene mutation status, (4) test for TP53 and IGHV gene mutation status and (5) no testing (ibrutinib for all).

METHOD

A decision analytic model (decision tree and partitioned survival model) was developed from the Australian healthcare system perspective with a lifetime horizon. Comparative treatment effects were estimated from indirect treatment comparisons and survival analysis using several studies. Costs, utility and adverse events were derived from public literature sources. Deterministic and probabilistic sensitivity analyses explored the impact of modeling uncertainties on outcomes.

RESULTS

Strategy 1 was associated with 5.69 quality-adjusted life-years (QALYs) and cost 458,836 Australian dollars (AUD). All other strategies had greater effectiveness but were more expensive than Strategy 1. At the willingness-to-pay (WTP) threshold of 100,000 AUD per QALY gained, Strategy 1 was most cost effective with an estimated probability of 68.8%. Strategy 4 was cost effective between thresholds 155,000-432,300 AUD per QALY gained, and Strategy 5 >432,300 AUD per QALY gained.

CONCLUSION

Population targeting using mutation testing for TP53 and IGHV when performed with del(17p) testing specifically in the context of frontline ibrutinib choice does not make a cost-ineffective treatment into a cost-effective treatment.

Negative feedback regulation of MAPK signaling is an important driver of chronic lymphocytic leukemia progression

Despite available targeted treatments for the disease, drug-resistant chronic lymphocytic leukemia (CLL) poses a clinical challenge. The objective of this study is to examine whether the dual-specific phosphatases DUSP1 and DUSP6 are required to negatively regulate mitogen-activated protein kinases (MAPKs) and thus counterbalance excessive MAPK activity. We show that high expression of DUSP6 in CLL correlates with poor clinical prognosis. Importantly, genetic deletion of the inhibitory phosphatase DUSP1 or DUSP6 and blocking DUSP1/6 function using a small-molecule inhibitor reduces CLL cell survival in vitro and in vivo. Using global phospho-proteome approaches, we observe acute activation of MAPK signaling by DUSP1/6 inhibition. This promotes accumulation of mitochondrial reactive oxygen species and, thereby, DNA damage and apoptotic cell death in CLL cells. Finally, we observe that DUSP1/6 inhibition is particularly effective against treatment-resistant CLL and therefore suggest transient DUSP1/6 inhibition as a promising treatment concept to eliminate drug-resistant CLL cells.

TP53 Gene 72 Arg/Pro (rs1042522) single nucleotide polymorphism increases the risk and the severity of chronic lymphocytic leukemia

Background

Genetic variations in TP53 gene are known to be important in chronic lymphocytic leukemia (CLL) and may cause its inactivation which is associated with an aggressive form of the disease. Single nucleotide polymorphism (rs1042522:G>C) in TP53 gene at codon 72 encodes for arginine (Arg) or proline (Pro) variant which results in amino acid substitution affecting the apoptotic potential of TP53 protein. The aim of this study was to assess the correlation between TP53 codon 72 polymorphism and risk susceptibility as well as severity of CLL among Tunisian patients.

Materials and methods

A case-control study was conducted in Tunisia from February 2019 to November 2021, 160 de novo CLL patients and 160 healthy volunteers matched in age and gender were involved. DNA was extracted from peripheral blood mononuclear cells and the rs1042522 was analyzed using PCR-RFLP.

Results

Pro variant was associated with higher susceptibility to CLL than Arg variant (p= 0.023). A significant association was found between Pro variant and prognostic classification of Binet stage C (p= 0.001), low hemoglobin level (p= 0.003) and low platelet count (p= 0.016).

Conclusion

We suggest that Pro variant may increase the risk of developing CLL in our population and could be associated with the severity of the disease.

Cytogenetics in the management of chronic lymphocytic leukemia: Guidelines from the Groupe Francophone de Cytogénétique Hématologique (GFCH)

Chromosomal abnormalities are frequent in chronic lymphocytic leukemia (CLL), and most have prognostic value. In addition to the four well-known abnormalities (13q, 11q and 17p deletions, and trisomy 12), other recurrent aberrations have been linked to the disease outcome and/or drug resistance. Moreover, the complex karyotype has recently emerged as a prognostic marker for patients undergoing immunochemotherapy or targeted therapies. Here, we describe the main chromosomal abnormalities identified in CLL and related disorders (small lymphocytic lymphoma and monoclonal B-cell lymphocytosis) by reviewing the most recent literature and discussing their detection and clinical impact. Lastly, we provide technical guidelines and a strategy for the cytogenetic assessment of CLL.

Novel precision medicine approaches and treatment strategies in hematological malignancies

Genetic testing has been applied for decades in clinical routine diagnostics of hematological malignancies to improve disease (sub)classification, prognostication, patient management, and survival. In recent classifications of hematological malignancies, disease subtypes are defined by key recurrent genetic alterations detected by conventional methods (i.e., cytogenetics, fluorescence in situ hybridization, and targeted sequencing). Hematological malignancies were also one of the first disease areas in which targeted therapies were introduced, the prime example being BCR::ABL1 inhibitors, followed by an increasing number of targeted inhibitors hitting the Achilles' heel of each disease, resulting in a clear patient benefit. Owing to the technical advances in high-throughput sequencing, we can now apply broad genomic tests, including comprehensive gene panels or whole-genome and whole-transcriptome sequencing, to identify clinically important diagnostic, prognostic, and predictive markers. In this review, we give examples of how precision diagnostics has been implemented to guide treatment selection and improve survival in myeloid (myelodysplastic syndromes and acute myeloid leukemia) and lymphoid malignancies (acute lymphoblastic leukemia, diffuse large B-cell lymphoma, and chronic lymphocytic leukemia). We discuss the relevance and potential of monitoring measurable residual disease using ultra-sensitive techniques to assess therapy response and detect early relapses. Finally, we bring up the promising avenue of functional precision medicine, combining ex vivo drug screening with various omics technologies, to provide novel treatment options for patients with advanced disease. Although we are only in the beginning of the field of precision hematology, we foresee rapid development with new types of diagnostics and treatment strategies becoming available to the benefit of our patients.

Subgroup-specific gene expression profiles and mixed epistasis in chronic lymphocytic leukemia

Understanding the molecular and phenotypic heterogeneity of cancer is a prerequisite for effective treatment. For chronic lymphocytic leukemia (CLL), recurrent genetic driver events have been extensively cataloged, but this does not suffice to explain the disease's diverse course. Here, we performed RNA sequencing on 184 CLL patient samples. Unsupervised analysis revealed two major, orthogonal axes of gene expression variation: the first one represented the mutational status of the immunoglobulin heavy variable (IGHV) genes, and concomitantly, the three-group stratification of CLL by global DNA methylation. The second axis aligned with trisomy 12 status and affected chemokine, MAPK and mTOR signaling. We discovered non-additive effects (epistasis) of IGHV mutation status and trisomy 12 on multiple phenotypes, including the expression of 893 genes. Multiple types of epistasis were observed, including synergy, buffering, suppression and inversion, suggesting that molecular understanding of disease heterogeneity requires studying such genetic events not only individually but in combination. We detected strong differentially expressed gene signatures associated with major gene mutations and copy number aberrations including SF3B1, BRAF and TP53, as well as del(17)(p13), del(13)(q14) and del(11)(q22.3) beyond dosage effect. Our study reveals previously underappreciated gene expression signatures for the major molecular subtypes in CLL and the presence of epistasis between them.

Evidence-Based Management of Chronic Lymphocytic Leukemia: Consensus Statements from the Gulf Region

INTRODUCTION

Despite recent advances in diagnosis, prognostication, and treatment options, chronic lymphocytic leukemia (CLL) is still a largely incurable disease. New concepts on diagnosis, staging, treatment, and follow-up on CLL have been incorporated throughout recent years. The lack of regional consensus guidelines has led to varying practices in the management of patients with CLL in the region. This manuscript aims to reach a consensus among expert hematologists regarding the definitions, classifications, and related practices of CLL. The experts developed a set of statements utilizing their personal experience together with the current literature on CLL management. This consensus aims to provide guidance for healthcare professionals involved in the management of CLL and serves as a step in developing regional guidelines.

METHODS

Eight experts responded to 50 statements regarding the diagnosis, staging, treatment, and prognosis of CLL with three potential answering alternatives ranging between agree, disagree, and abstain. This consensus adopted a modified Delphi consensus methodology. A consensus was reached when at least 75% of the agreement to the answer was reached. This manuscript presents the scientific insights of the participating attendees, panel discussions, and the supporting literature review.

RESULTS

Of the 50 statements, a consensus was reached on almost all statements. Statements covered CLL-related topics, including diagnostic evaluation, staging, risk assessment, different patient profiles, prognostic evaluation, treatment decisions, therapy sequences, response evaluation, complications, and CLL during the COVID-19 pandemic.

CONCLUSION

In recent years, CLL management has progressed significantly, with many diagnostic tests and several novel treatments becoming available. This consensus gathers decades of consolidated principles, novel research, and promising prospects for the management of this disease.

Chronic lymphocytic leukaemia Australasian consensus practice statement

Chronic lymphocytic leukaemia (CLL) is the most common haematological malignancy in Australia and New Zealand (ANZ). Considerable changes to diagnostic and management algorithms have occurred within the last decade. The availability of next-generation sequencing and measurable residual disease assessment by flow cytometry allow for advanced prognostication and response assessments. Novel therapies, including inhibitors of Bruton's tyrosine kinase (BTKi) and B-cell lymphoma 2 (BCL2) inhibitors, have transformed the treatment landscape for both treatment-naïve and relapsed/refractory disease, particularly for patients with high-risk genetic aberrations. Recommendations regarding appropriate supportive management continue to evolve, and special considerations are required for patients with CLL with respect to the global SARS-CoV-2 pandemic. The unique funding and treatment environments in Australasia highlight the need for specific local guidance with respect to the investigation and management of CLL. This consensus practice statement was developed by a broadly representative group of ANZ experts in CLL with endorsement by peak haematology bodies, with a view to providing this standardised guidance.

Treatment pattern of chronic lymphocytic leukemia/small lymphocytic lymphoma in Korea: a multicenter retrospective study (KCSG LY20-06)

BACKGROUND/AIMS

Little attention is paid to chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) in Korea due to the rarity of the disease. With its rising incidence, we aimed to evaluate recent changes in treatment patterns and survival outcomes of patients with CLL/SLL.

METHODS

A total of 141 patients diagnosed with CLL/SLL between January 2010 and March 2020 who received systemic therapy were analyzed in this multicenter retrospective study.

RESULTS

The median patient age was 66 years at diagnosis, and 68.1% were male. The median interval from diagnosis to initial treatment was 0.9 months (range: 0-77.6 months), and the most common treatment indication was progressive marrow failure (50.4%). Regarding first-line therapy, 46.8% received fludarabine, cyclophosphamide, plus rituximab (FCR), followed by chlorambucil (19.9%), and obinutuzumab plus chlorambucil (GC) (12.1%). The median progression-free survival (PFS) was 49.3 months (95% confidence interval [CI], 32.7-61.4), and median overall survival was not reached (95% CI, 98.4 mo- not reached). Multivariable analysis revealed younger age (≤ 65 yr) (hazard ratio [HR], 0.46; p < 0.001) and first-line therapy with FCR (HR, 0.64; p = 0.019) were independently associated with improved PFS. TP53 aberrations were observed in 7.0% (4/57) of evaluable patients. Following reimbursement, GC became the most common therapy among patients over 65 years and second in the overall population after 2017.

CONCLUSION

Age and reimbursement mainly influenced treatment strategies. Greater effort to apply risk stratifications into practice and clinical trials for novel agents could help improve treatment outcomes in Korean patients.

Copy Number Variations and Gene Mutations Identified by Multiplex Ligation-Dependent Probe Amplification in Romanian Chronic Lymphocytic Leukemia Patients

Chronic lymphocytic leukemia (CLL) is known for its wide-ranging clinical and genetic diversity. The study aimed to assess the associations between copy number variations (CNVs) and various biological and clinical features, as well as the survival rates of CLL patients and to evaluate the effectiveness of the multiplex ligation-dependent probe amplification (MLPA) technique in CLL patients.DNA was extracted from 110 patients, and MLPA was performed. Mutations in NOTCH1, SF3B1, and MYD88 were also analyzed. A total of 52 patients showed at least one CNV, 26 had at least one somatic mutation, and 10 presented both, CNVs, and somatic mutations. The most commonly identified CNVs were del(114.3), del(11q22.3), and dup(12q23.2). Other CNVs identified included del(17p13.1), del(14q32.33), dup(10q23.31), and del(19p13.2). One patient was identified with concomitant trisomy 12, 13, and 19. NOTCH1 and SF3B1 mutations were found in 13 patients each, either alone or in combination with other mutations or CNVs, while MYD88 mutation was identified in one patient. Forty-two patients had normal results. Associations between the investigated CNVs and gene mutations and patients' overall survival were found. The presence of NOTCH1 and SF3B1 mutations or the combination of NOTCH1 mutation and CNVs significantly influenced the survival of patients with CLL. Both mutations are frequently associated with different CNVs. Del(13q) is associated with the longest survival rate, while the shortest survival is found in patients with del(17p). Even if MLPA has constraints, it may be used as the primary routine analysis in patients with CLL.

Role of microRNAs in Chronic Lymphocytic Leukemia

Chronic Lymphocytic Leukemia (CLL) is the most common form of leukemia in adults, with a highly variable clinical course. Improvement in the knowledge of the molecular pathways behind this disease has led to the development of increasingly specific therapies, such as BCR signaling inhibitors and BCL-2 inhibitors. In this context, the emerging role of microRNAs (miRNAs) in CLL pathophysiology and their possible application in therapy is worth noting. MiRNAs are one of the most important regulatory molecules of gene expression. In CLL, they can act both as oncogenes and tumor suppressor genes, and the deregulation of specific miRNAs has been associated with prognosis, progression, and drug resistance. In this review, we describe the role of the miRNAs that primarily impact the disease, and how these miRNAs could be used as therapeutic tools. Certainly, the use of miRNAs in clinical practice is still limited in CLL. Many issues still need to be solved, particularly regarding their biological and safety profile, even if several studies have suggested their efficacy on the disease, alone or in combination with other drugs.

Outcomes in Patients with High-Risk Features after Fixed-Duration Ibrutinib plus Venetoclax: Phase II CAPTIVATE Study in First-Line Chronic Lymphocytic Leukemia

PURPOSE

The CAPTIVATE study investigated first-line ibrutinib plus venetoclax for chronic lymphocytic leukemia in 2 cohorts: minimal residual disease (MRD)-guided randomized discontinuation (MRD cohort) and Fixed Duration (FD cohort). We report outcomes of fixed-duration ibrutinib plus venetoclax in patients with high-risk genomic features [del(17p), TP53 mutation, and/or unmutated immunoglobulin heavy chain (IGHV)] in CAPTIVATE.

PATIENTS AND METHODS

Patients received three cycles of ibrutinib 420 mg/day then 12 cycles of ibrutinib plus venetoclax (5-week ramp-up to 400 mg/day). FD cohort patients (n = 159) received no further treatment. Forty-three MRD cohort patients with confirmed undetectable MRD (uMRD) after 12 cycles of ibrutinib plus venetoclax received randomized placebo treatment.

RESULTS

Of 195 patients with known status of genomic risk features at baseline, 129 (66%) had ≥1 high-risk feature. Overall response rates were >95% regardless of high-risk features. In patients with and without high-risk features, respectively, complete response (CR) rates were 61% and 53%; best uMRD rates: 88% and 70% (peripheral blood) and 72% and 61% (bone marrow); 36-month progression-free survival (PFS) rates: 88% and 92%. In subsets with del(17p)/TP53 mutation (n = 29) and unmutated IGHV without del(17p)/TP53 mutation (n = 100), respectively, CR rates were 52% and 64%; uMRD rates: 83% and 90% (peripheral blood) and 45% and 80% (bone marrow); 36-month PFS rates: 81% and 90%. Thirty-six-month overall survival (OS) rates were >95% regardless of high-risk features.

CONCLUSIONS

Deep, durable responses and sustained PFS seen with fixed-duration ibrutinib plus venetoclax are maintained in patients with high-risk genomic features, with similar PFS and OS to those without high-risk features. See related commentary by Rogers, p. 2561.

Treatment Refractoriness in Chronic Lymphocytic Leukemia: Old and New Molecular Biomarkers

Chronic lymphocytic leukemia (CLL) is the most common leukemia in adults. Despite its indolent clinical course, therapy refractoriness and disease progression still represent an unmet clinical need. Before the advent of pathway inhibitors, chemoimmunotherapy (CIT) was the commonest option for CLL treatment and is still widely used in areas with limited access to pathway inhibitors. Several biomarkers of refractoriness to CIT have been highlighted, including the unmutated status of immunoglobulin heavy chain variable genes and genetic lesions of TP53, BIRC3 and NOTCH1. In order to overcome resistance to CIT, targeted pathway inhibitors have become the standard of care for the treatment of CLL, with practice-changing results obtained through the inhibitors of Bruton tyrosine kinase (BTK) and BCL2. However, several acquired genetic lesions causing resistance to covalent and noncovalent BTK inhibitors have been reported, including point mutations of both BTK (e.g., C481S and L528W) and PLCG2 (e.g., R665W). Multiple mechanisms are involved in resistance to the BCL2 inhibitor venetoclax, including point mutations that impair drug binding, the upregulation of BCL2-related anti-apoptotic family members, and microenvironmental alterations. Recently, immune checkpoint inhibitors and CAR-T cells have been tested for CLL treatment, obtaining conflicting results. Potential refractoriness biomarkers to immunotherapy were identified, including abnormal levels of circulating IL-10 and IL-6 and the reduced presence of CD27⁺CD45RO^- CD8⁺ T cells.

Therapeutic Targeting of P53: A Comparative Analysis of APR-246 and COTI-2 in Human Tumor Primary Culture 3-D Explants

Background: TP53 is the most commonly mutated gene in human cancer with loss of function mutations largely concentrated in “hotspots” affecting DNA binding. APR-246 and COTI-2 are small molecules under investigation in P53 mutated cancers. APR binds to P53 cysteine residues, altering conformation, while COTI-2 showed activity in P53 mutant tumors by a computational platform. We compared APR-246 and COTI-2 activity in human tumor explants from 247 surgical specimens. Methods: Ex vivo analyses of programmed cell death measured drug-induced cell death by delayed-loss-of-membrane integrity and ATP content. The LC50s were compared by Z-Score. Synergy was conducted by the method of Chou and Talalay, and correlations were performed by Pearson moment. Results: APR-246 and COTI-2 activity favored hematologic neoplasms, but solid tumor activity varied by diagnosis. COTI-2 and APR-246 activity did not correlate (R = 0.1028) (NS). COTI-2 activity correlated with nitrogen mustard, cisplatin and gemcitabine, doxorubicin and selumetinib, with a trend for APR-246 with doxorubicin. For ovarian cancer, COTI-2 showed synergy with cisplatin at 25%. Conclusions: COTI-2 and APR-246 activity differ by diagnosis. A lack of correlation supports distinct modes of action. Cisplatin synergy is consistent with P53’s role in DNA damage. Different mechanisms of action may underlie disease specificity and offer better disease targeting.

Prognostication of DNA Damage Response Protein Expression Patterns in Chronic Lymphocytic Leukemia

Proteomic DNA Damage Repair (DDR) expression patterns in Chronic Lymphocytic Leukemia were characterized by quantifying and clustering 24 total and phosphorylated DDR proteins. Overall, three protein expression patterns (C1-C3) were identified and were associated as an independent predictor of distinct patient overall survival outcomes. Patients within clusters C1 and C2 had poorer survival outcomes and responses to fludarabine, cyclophosphamide, and rituxan chemotherapy compared to patients within cluster C3. However, DDR protein expression patterns were not prognostic in more modern therapies with BCL2 inhibitors or a BTK/PI3K inhibitor. Individually, nine of the DDR proteins were prognostic for predicting overall survival and/or time to first treatment. When looking for other proteins that may be associated with or influenced by DDR expression patterns, our differential expression analysis found that cell cycle and adhesion proteins were lower in clusters compared to normal CD19 controls. In addition, cluster C3 had a lower expression of MAPK proteins compared to the poor prognostic patient clusters thus implying a potential regulatory connection between adhesion, cell cycle, MAPK, and DDR signaling in CLL. Thus, assessing the proteomic expression of DNA damage proteins in CLL provided novel insights for deciphering influences on patient outcomes and expanded our understanding of the potential complexities and effects of DDR cell signaling.

In-depth circulating tumor DNA sequencing for prognostication and monitoring in natural killer/T-cell lymphomas

Background

Epstein-Barr virus (EBV) quantitation and current imaging modalities are used for diagnosis and disease monitoring in Extranodal NK/T cell lymphoma (ENKTL) but have limitations. Thus, we explored the utility of circulating tumor DNA (ctDNA) as a diagnostic biomarker.

Methods

Through in-depth sequencing of 118 blood samples collected longitudinally at different time points from 45 patients, we examined the mutational profile of each sample, estimated its impact on the clinical outcome, and assessed its role as a biomarker in comparison with EBV DNA quantitation.

Results

The ctDNA concentration was correlated with treatment response, stage, and EBV DNA quantitation. The detection rate of ctDNA mutation was 54.5%, with BCOR (21%) being the most commonly mutated gene in newly diagnosed patients; TP53 mutation (33%) was the most prevalent in patients that experienced a relapse. Additionally, patients in complete remission exhibited a rapid clearance of ENKTL-related somatic mutations, while relapsed patients frequently presented with persisting or emerging mutations. We detected ctDNA mutations in EBV-negative patients (50%) and mutation clearance in EBV-positive patients in remission, suggesting ctDNA genotyping as an efficient complementary monitoring method for ENKTL. Additionally, mutated DDX3X (PFS HR, 8.26) in initial samples predicted poor outcome.

Conclusion

Our results suggest that ctDNA analysis can be used to genotype at diagnosis and estimate the tumor burden in patients with ENKTL. Furthermore, ctDNA dynamics indicate the potential use of testing it to monitor therapeutic responses and develop new biomarkers for precision ENKTL therapy.

Different prognostic impact of recurrent gene mutations in chronic lymphocytic leukemia depending on IGHV gene somatic hypermutation status: a study by ERIC in HARMONY

Recent evidence suggests that the prognostic impact of gene mutations in patients with chronic lymphocytic leukemia (CLL) may differ depending on the immunoglobulin heavy variable (IGHV) gene somatic hypermutation (SHM) status. In this study, we assessed the impact of nine recurrently mutated genes (BIRC3, EGR2, MYD88, NFKBIE, NOTCH1, POT1, SF3B1, TP53, and XPO1) in pre-treatment samples from 4580 patients with CLL, using time-to-first-treatment (TTFT) as the primary end-point in relation to IGHV gene SHM status. Mutations were detected in 1588 (34.7%) patients at frequencies ranging from 2.3-9.8% with mutations in NOTCH1 being the most frequent. In both univariate and multivariate analyses, mutations in all genes except MYD88 were associated with a significantly shorter TTFT. In multivariate analysis of Binet stage A patients, performed separately for IGHV-mutated (M-CLL) and unmutated CLL (U-CLL), a different spectrum of gene alterations independently predicted short TTFT within the two subgroups. While SF3B1 and XPO1 mutations were independent prognostic variables in both U-CLL and M-CLL, TP53, BIRC3 and EGR2 aberrations were significant predictors only in U-CLL, and NOTCH1 and NFKBIE only in M-CLL. Our findings underscore the need for a compartmentalized approach to identify high-risk patients, particularly among M-CLL patients, with potential implications for stratified management.

Canadian evidence-based guideline for frontline treatment of chronic lymphocytic leukemia: 2022 update

Chronic lymphocytic leukemia (cll) is the most common adult leukemia in North America. In 2018, the first unified national guideline in Canada was developed for the front-line treatment of cll that helped guide treatment across the country. As an update in 2022, a group of clinical experts from across Canada came together to provide input and guidance that included new and innovative treatments and approaches that will continue to provide health care professionals with clear guidance on the first-line management of cll. Recommendations were provided in consensus based on available evidence for the first-line treatment of cll.

Precision diagnostics in chronic lymphocytic leukemia: Past, present and future

Genetic diagnostics of hematological malignancies has evolved dramatically over the years, from chromosomal banding analysis to next-generation sequencing, with a corresponding increased capacity to detect clinically relevant prognostic and predictive biomarkers. In diagnostics of patients with chronic lymphocytic leukemia (CLL), we currently apply fluorescence in situ hybridization (FISH)-based analysis to detect recurrent chromosomal aberrations (del(11q), del(13q), del(17p) and trisomy 12) as well as targeted sequencing (IGHV and TP53 mutational status) for risk-stratifying purposes. These analyses are performed before start of any line of treatment and assist in clinical decision-making including selection of targeted therapy (BTK and BCL2 inhibitors). Here, we present the current view on the genomic landscape of CLL, including an update on recent advances with potential for clinical translation. We discuss different state-of-the-art technologies that are applied to enable precision diagnostics in CLL and highlight important genomic markers with current prognostic and/or predictive impact as well as those of prospective clinical relevance. In the coming years, it will be important to develop more comprehensive genomic analyses that can capture all types of relevant genetic aberrations, but also to develop highly sensitive assays to detect minor mutations that affect therapy response or confer resistance to targeted therapies. Finally, we will bring up the potential of new technologies and multi-omics analysis to further subclassify the disease and facilitate implementation of precision medicine approaches in this still incurable disease.

Resistance to Bruton tyrosine kinase inhibition in chronic lymphocytic leukaemia and non-Hodgkin lymphoma

Bruton tyrosine kinase inhibitors (BTKi) have transformed the therapeutic landscape of chronic lymphocytic leukaemia (CLL) and non-Hodgkin lymphoma. However, primary and acquired resistance to BTKi can be seen due to a variety of mechanisms including tumour intrinsic and extrinsic mechanisms such as gene mutations, activation of bypass signalling pathways and tumour microenvironment. Herein, we provide an updated review of the key clinical data of BTKi treatment in CLL, mantle cell lymphoma, and diffuse large B-cell lymphoma (DLBCL). We incorporate the most recent findings regarding mechanisms of resistance to covalent and non-covalent inhibitors, including ibrutinib, acalabrutinib, zanubrutinib and pirtobrutinib. We also cover the clinical sensitivity of certain molecular subtypes of DLBCL to an ibrutinib-containing regimen. Lastly, we summarise ongoing clinical investigations aimed at overcoming resistance via use of BTKi-containing combined therapies or the novel non-covalent BTKi. The review article targets an audience of clinical practitioners, clinical investigators and translational researchers.

The spectrum of subclonal TP53 mutations in chronic lymphocytic leukemia: A next generation sequencing retrospective study

Chronic lymphocytic leukemia (CLL) is a hematological disorder with complex clinical and biological behavior. TP53 mutational status and cytogenetic assessment of the deletion of the corresponding locus (17p13.1) are considered the most relevant biomarkers associated with pharmaco-predictive response, chemo-refractoriness, and worse prognosis in CLL patients. The implementation of Next Generation Sequencing (NGS) methodologies in the clinical laboratory allows for comprehensively analyzing the TP53 gene and detecting mutations with allele frequencies ≤10%, that is, "subclonal mutations". We retrospectively studied TP53 gene mutational status by NGS in 220 samples from 171 CLL patients. TP53 mutations were found in 60/220 (27.3%) samples and 47/171 (27.5%) patients. Interestingly, subclonal mutations could be detected in 31/60 samples (51.7%) corresponding to 25 patients (25/47, 53.2%). We identified 44 distinct subclonal TP53 mutations clustered in the central DNA-binding domain of p53 protein (exons 5-8, codons 133-286). Missense mutations were predominant (>80%), whereas indels, nonsense, and splice site variants were less represented. All subclonal TP53 variants but one [p.(Pro191fs)] were already described in NCI and/or Seshat databases as "damaging" and/or "probably damaging" mutations (38/44, 86% and 6/44, 14%, respectively). Longitudinal samples were available for 37 patients. Almost half of them displayed at least one TP53 mutant subclone, which could be alone (4/16, 25%) or concomitant with other TP53 mutant clonal ones (12/16, 75%); different patterns of mutational dynamics overtimes were documented. In conclusion, utilization of NGS in our "real-life" cohort of CLL patients demonstrated an elevated frequency of subclonal TP53 mutations. This finding indicates the need for precisely identifying these mutations during disease since the clones carrying them may become predominant and be responsible for therapy failures.

IgD multiple myeloma: biology, diagnosis, and treatment

IgD multiple myeloma is uncommon. Patients generally present at a younger age and have shorter progression free and overall survivals (OSs). Its rarity has inhibited development of a specific risk stratification system or informed best treatment protocols. We present interphase fluorescence in situ hybridization results from a group of 29 cases. These showed evidence of a decreased male to female ratio, decreased OS in patients aged 70 and over, better outcomes in those with kappa light chain restriction, and CD56 positive patients had longer survivals than those lacking CD56. We discuss the biology of IgD multiple myeloma, the need for prospective studies, and challenges for improvements in diagnosis and treatment. We suggest an International Register to accelerate development of best practice guidelines for diagnosis, risk stratification, and treatment.

Patterns of use of biological and genetic markers for chronic lymphocytic leukemia and acute myeloid leukemia in Puerto Rico

BACKGROUND

The use of markers has stimulated the development of more appropriate targeted therapies for chronic lymphocytic leukemia (CLL) and acute myeloid leukemia (AML). We assessed the use and prevalence of biological and genetic markers of CLL and AML in the homogeneous Hispanic population of Puerto Rico.

METHODS

We used the Puerto Rico CLL/AML Population-Based Registry, which combines information from linked databases. Logistic regression models were used to examine factors associated with biological and genetic testing.

RESULTS

A total of 926 patients 18 years or older diagnosed with CLL (n = 518) and AML (n = 408) during 2011-2015 were included in this analysis. Cytogenetic testing (FISH) was reported for 441 (85.1%) of the CLL patients; of those, 24.0% had the presence of trisomy 12, 9.5% carried deletion 11q, 50.3% carried deletion 13q, and 6.3% carried deletion 17p. Regarding AML, patients with cytogenetics and molecular tests were considered to determine the risk category (254 patients), of which 39.8% showed poor or adverse risk. Older age and having more comorbidities among patients with CLL were associated with a lower likelihood of receiving a FISH test.

CONCLUSIONS

Although prognostic genetic testing is required for treatment decisions, the amount of testing in this Hispanic cohort is far from ideal. Furthermore, some tests were not homogeneously distributed in the population, which requires further exploration and monitoring. This study contributes to the field by informing the medical community about the use and prevalence of biological and genetic markers of CLL and AML. Similarly, it has the potential to improve the management of CLL and AML through benchmarking.

Low CD49d expression in newly diagnosed chronic lymphocytic leukaemia may be associated with high-risk features and reduced treatment-free-intervals

This study was carried out to assess the prognostic power of low CD49d expression (≥10%) in newly diagnosed CLL patients using a previously described cohort. Eighty-five patients were included. Median age at diagnosis; 70 years (43-88); CD49d was expressed in 33/85 (38.8%); 23/33 (69.7%) at ≥30% referred to as 'HiCD49d' and 10/33 (30.3%) between 10 and 30% with a bimodal pattern on scatterplot analysis referred to as 'LoCD49d'. Eleven patients (12.9%) presented as Binet stage B, of whom 8 (72.7%) were CD49d+ (HiCD49d 7/8; LoCD49d 1/8). Seven of 81 patients (8.6%) were NOTCH1 mutated and all were CD49d+ (p ≤ .01). IgVH analysis was performed on 29 (87.8%) of the CD49d+ cases, of whom 21 (72.4%) were unmutated and 8 (27.6%) were mutated. CD38+/CD49d+ accounted for 11/20 (55%) (CD38+/HiCD49D: 9/11; CD38+/LoCD49D: 2/11). At 42 months, treatment had been initiated in 18/85 (21%) patients, of these 10/33 (30.3%) were CD49d+ versus 8/52 (15.4%) of the CD49d- group. The median treatment free interval for the CD49d+ group was 11 months (HiCD49d; 14.5 months, LoCD49d; 11 months) compared to 21.5 months for the CD49d- group. These findings suggest that the predictive value of CD49d expression is retained at expression levels down to 10%.

Current insights into the regulation of programmed cell death by TP53 mutation in cancer

Gene mutation is a complicated process that influences the onset and progression of cancer, and the most prevalent mutation involves the TP53 gene. One of the ways in which the body maintains homeostasis is programmed cell death, which includes apoptosis, autophagic cell death, pyroptosis, ferroptosis, NETosis, and the more recently identified process of cuprotosis. Evasion of these cell deaths is a hallmark of cancer cells, and our elucidation of the way these cells die helps us better understands the mechanisms by which cancer arises and provides us with more ways to treat it.Studies have shown that programmed cell death requires wild-type p53 protein and that mutations of TP53 can affect these modes of programmed cell death. For example, mutant p53 promotes iron-dependent cell death in ferroptosis and inhibits apoptotic and autophagic cell death. It is clear that TP53 mutations act on more than one pathway to death, and these pathways to death do not operate in isolation. They interact with each other and together determine cell death. This review focuses on the mechanisms via which TP53 mutation affects programmed cell death. Clinical investigations of TP53 mutation and the potential for targeted pharmacological agents that can be used to treat cancer are discussed.

Towards precision medicine in lymphoid malignancies

Careful histopathologic examination remains the cornerstone in the diagnosis of the clinically and biologically heterogeneous group of lymphoid malignancies. However, recent advances in genomic and epigenomic characterization using high-throughput technologies have significantly improved our understanding of these tumors. Although no single genomic alteration is completely specific for a lymphoma entity, some alterations are highly recurrent in certain entities and thus can provide complementary diagnostic information when integrated in the hematopathological diagnostic workup. Moreover, other alterations may provide important information regarding the clinical course, that is, prognostic or risk-stratifying markers, or response to treatment, that is, predictive markers, which may allow tailoring of the patient's treatment based on (epi)genetic characteristics. In this review, we will focus on clinically relevant diagnostic, prognostic, and predictive biomarkers identified in more common types of B-cell malignancies, and discuss how diagnostic assays designed for comprehensive molecular profiling may pave the way for the implementation of precision diagnostics/medicine approaches. We will also discuss future directions in this rapidly evolving field, including the application of single-cell sequencing and other omics technologies, to decipher clonal dynamics and evolution in lymphoid malignancies.

Application of precision medicine in clinical routine in haematology-Challenges and opportunities

Precision medicine is revolutionising patient care in cancer. As more knowledge is gained about the impact of specific genetic lesions on diagnosis, prognosis and treatment response, diagnostic precision and the possibility for optimal individual treatment choice have improved. Identification of hallmark genetic aberrations such as the BCR::ABL1 gene fusion in chronic myeloid leukaemia (CML) led to the rapid development of efficient targeted therapy and molecular follow-up, vastly improving survival for patients with CML during recent decades. The assessment of translocations, copy number changes and point mutations are crucial for the diagnosis and risk stratification of acute myeloid leukaemia and myelodysplastic syndromes. Still, the often heterogeneous and complex genetic landscape of haematological malignancies presents several challenges for the implementation of precision medicine to guide diagnosis, prognosis and treatment choice. This review provides an introduction and overview of the important molecular characteristics and methods currently applied in clinical practice to guide clinical decision making in haematological malignancies of myeloid and lymphoid origin. Further, experimental ways to guide the choice of targeted therapy for refractory patients are reviewed, such as functional precision medicine using drug profiling. An example of the use of pipeline studies where the treatment is chosen according to the molecular characteristics in rare solid malignancies is also provided. Finally, the future opportunities and remaining challenges of precision medicine in the real world are discussed.

Genetic Testing at Diagnosis Has Prognostic Value in Patients with Chronic Lymphocytic Leukemia including at Early Stages

Chronic lymphocytic leukemia (CLL) has a variable clinical evolution, with some patients living treatment-free for decades while others require therapy shortly after diagnosis. In a consecutive series of 217 CLL patients, molecular biomarkers with prognostic value (IGHV status, TP53 mutations, and cytogenetics), whose analysis is recommended prior to treatment start, were studied at diagnosis. Multivariate analyses identified prognostic variables for overall survival (OS) and time to first treatment (TTFT) and validated the CLL-IPI and IPS-E variables for all or early-stage patients (Rai 0–2/Binet A), respectively. Unmutated IGHV was associated with shorter OS and TTFT, even for early-stage patients. Lymphocyte count was not statistically significant for TTFT of early-stage patients in multivariate analysis. Our results validate the prognostic value of IGHV mutational status at diagnosis for OS and TTFT, including for early stages. Our findings suggest a role for molecular and mutational analysis at diagnosis in future prospective studies.

TRAF3 alterations are frequent in del-3'IGH chronic lymphocytic leukemia patients and define a specific subgroup with adverse clinical features

Interstitial 14q32 deletions involving IGH gene are infrequent events in chronic lymphocytic leukemia (CLL), affecting less than 5% of patients. To date, little is known about their clinical impact and molecular underpinnings, and its mutational landscape is currently unknown. In this work, a total of 871 CLLs were tested for the IGH break-apart probe, and 54 (6.2%) had a 300 kb deletion of 3'IGH (del-3'IGH CLLs), which contributed to a shorter time to first treatment (TFT). The mutational analysis by next-generation sequencing of 317 untreated CLLs (54 del-3'IGH and 263 as the control group) showed high mutational frequencies of NOTCH1 (30%), ATM (20%), genes involved in the RAS signaling pathway (BRAF, KRAS, NRAS, and MAP2K1) (15%), and TRAF3 (13%) within del-3'IGH CLLs. Notably, the incidence of TRAF3 mutations was significantly higher in del-3'IGH CLLs than in the control group (p < .001). Copy number analysis also revealed that TRAF3 loss was highly enriched in CLLs with 14q deletion (p < .001), indicating a complete biallelic inactivation of this gene through deletion and mutation. Interestingly, the presence of mutations in the aforementioned genes negatively refined the prognosis of del-3'IGH CLLs in terms of overall survival (NOTCH1, ATM, and RAS signaling pathway genes) and TFT (TRAF3). Furthermore, TRAF3 biallelic inactivation constituted an independent risk factor for TFT in the entire CLL cohort. Altogether, our work demonstrates the distinct genetic landscape of del-3'IGH CLL with multiple molecular pathways affected, characterized by a TRAF3 biallelic inactivation that contributes to a marked poor outcome in this subgroup of patients.

TP53 Mutations Identified Using NGS Comprise the Overwhelming Majority of TP53 Disruptions in CLL: Results From a Multicentre Study

Limited data exists to show the correlation of (tumour protein 53) TP53 mutation detected by Next generation sequencing (NGS) and the presence/absence of deletions of 17p13 detected by FISH. The study which is the largest series to date includes 2332 CLL patients referred for analysis of del(17p) by FISH and TP53 mutations by NGS before treatment. Using a 10% variant allele frequency (VAF) threshold, cases were segregated into high burden mutations (≥10%) and low burden mutations (<10%). TP53 aberrations (17p [del(17p)] and/or TP53 mutation) were detected in 320/2332 patients (13.7%). Using NGS analysis, 429 TP53 mutations were identified in 303 patients (13%). Of these 238 (79%) and 65 (21%) were cases with high burden and low burden mutations respectively. In our cohort, 2012 cases did not demonstrate a TP53 aberration (86.3%). A total of 159 cases showed TP53 mutations in the absence of del(17p) (49/159 with low burden TP53 mutations) and 144 cases had both TP53 mutation and del(17p) (16/144 with low burden mutations). Only 17/2332 (0.7%) cases demonstrated del(17p) with no TP53 mutation. Validated NGS protocols should be used in clinical decision making to avoid missing low-burden TP53 mutations and can detect the vast majority of TP53 aberrations.

Extracellular vesicles and PDL1 suppress macrophages inducing therapy resistance in TP53-deficient B-cell malignancies

Genetic alterations in the DNA Damage Response (DDR) pathway are a frequent mechanism of resistance to CIT in B-cell malignancies. We have previously shown that the synergy of CIT relies on secretory crosstalk elicited by chemotherapy between the tumour cells and macrophages. Here, we show that loss of multiple different members of the DDR pathway inhibits macrophage phagocytic capacity in vitro and in vivo. Particularly loss of TP53 led to decreased phagocytic capacity ex vivo across multiple B-cell malignancies. We demonstrate via in vivo cyclophosphamide treatment using the Eµ-TCL1 mouse model that loss of macrophage phagocytic capacity in Tp53-deleted leukemia is driven by a significant downregulation of a phagocytic transcriptomic signature using scRNA-Seq. By analysing the tumour B-cell proteome, we identified a TP53 specific upregulation of proteins associated with extracellular vesicles (EV). We abrogated EV biogenesis in tumour B-cells via CRISPR-knockout (KO) of RAB27A and confirmed that the EVs from TP53-deleted lymphoma cells were responsible for the reduced phagocytic capacity and the in vivo CIT resistance. Furthermore, we observed that TP53 loss led to an upregulation of both PD-L1 cell surface expression and secretion of EVs by lymphoma cells. Disruption of EV bound PD-L1 by anti-PD-L1 antibodies or PD-L1 CRISPR-KO improved macrophage phagocytic capacity and in vivo therapy response. Thus, we demonstrate enhanced EV-release and increased PD-L1 expression in TP53-deficient B-cell lymphomas as novel mechanisms of macrophage function alteration in CIT resistance. This study indicates the use of checkpoint inhibition in the combination treatment of B-cell malignancies with TP53 loss.

Impact of Low-Burden TP53 Mutations in the Management of CLL

In chronic lymphocytic leukemia (CLL), TP53 abnormalities are associated with reduced survival and resistance to chemoimmunotherapy (CIT). The recommended threshold to clinically report TP53 mutations is a matter of debate given that next-generation sequencing technologies can detect mutations with a limit of detection of approximately 1% with high confidence. However, the clinical impact of low-burden TP53 mutations with a variant allele frequency (VAF) of less than 10% remains unclear. Longitudinal analysis before and after fludarabine based on NGS sequencing demonstrated that low-burden TP53 mutations were present before the onset of treatment and expanded at relapse to become the predominant clone. Most studies evaluating the prognostic or predictive impact of low-burden TP53 mutations in untreated patients show that low-burden TP53 mutations have the same unfavorable prognostic impact as clonal defects. Moreover, studies designed to assess the predictive impact of low-burden TP53 mutations showed that TP53 mutations, irrespective of mutation burden, have an inferior impact on overall survival for CIT-treated patients. As low-burden and high-burden TP53 mutations have comparable clinical impacts, redefining the VAF threshold may have important implications for the clinical management of CLL.

Long-term efficacy of first-line ibrutinib treatment for chronic lymphocytic leukaemia in patients with TP53 aberrations: a pooled analysis from four clinical trials

TP53 aberrations [del(17p) or TP53 mutation] predict poor survival with chemoimmunotherapy in patients with chronic lymphocytic leukaemia (CLL). We evaluated long-term efficacy and safety of first-line ibrutinib-based therapy in patients with CLL bearing TP53 aberrations in a pooled analysis across four studies: PCYC-1122e, RESONATE-2 (PCYC-1115/16), iLLUMINATE (PCYC-1130) and ECOG-ACRIN E1912. The pooled analysis included 89 patients with TP53 aberrations receiving first-line treatment with single-agent ibrutinib (n = 45) or ibrutinib in combination with an anti-CD20 antibody (n = 44). All 89 patients had del(17p) (53% of 89 patients) and/or TP53 mutation (91% of 58 patients with TP53 sequencing results available). With a median follow-up of 49·8 months (range, 0·1-95·9), median progression-free survival was not reached. Progression-free survival rate and overall survival rate estimates at four years were 79% and 88%, respectively. Overall response rate was 93%, including complete response in 39% of patients. No new safety signals were identified in this analysis. Forty-six percent of patients remained on ibrutinib treatment at last follow-up. With median follow-up of four years (up to eight years), results from this large, pooled, multi-study data set suggest promising long-term outcomes of first-line ibrutinib-based therapy in patients with TP53 aberrations. Registered at ClinicalTrials.gov (NCT01500733, NCT01722487, NCT02264574 and NCT02048813).

Atypical "accelerated" chronic lymphocytic leukemia with abnormal lymphocyte chromatin clumping, bone involvement, and exceptional response to Imbruvica

BACKGROUND

The "accelerated" chronic lymphocytic leukemia (aCLL) is a relatively rare form of CLL progression. The expanded proliferation centers in aCLL have been associated with adverse prognostic features and propensity to more aggressive behavior with shorter survival.

CASE

An atypical case of aCLL with distinct features is described. A 66-year-old female presented with a marrow replacing process associated with multiple osseous metastases and trivial lymphadenopathy. Bone biopsy revealed an unspecified low-grade B cell lymphoproliferative disorder that demonstrated a suboptimal response to standard chemotherapy. Subsequent lymph node biopsy demonstrated findings consisted with aCLL. The distinguishing features of the case were, in addition to bone involvement, the lagging peripheral lymphocytosis and a striking pattern of the chromatin clumping with a prominent "shattered" appearance reminiscent of Pelger-Huet-like dysplastic anomaly. A targeted next-generation sequencing (NGS) assay detected pathogenic mutations in TP53 and SF3B1. In contrast to chemotherapy, the case demonstrated an excellent response to imbruvica.

CONCLUSION

The noted peculiarities could potentially distinguish this case as a novel, rare variant of aCLL.