Chromosomal translocations and karyotype complexity in chronic lymphocytic leukemia: a systematic reappraisal of classic cytogenetic data

An overview of prognostic markers in patients with CLL

Chronic lymphocytic leukemia (CLL) is a low-grade B-cell lymphoproliferative disorder. It is the most prevalent type of leukemia in the western countries, with a median age at diagnosis of 70 years. In 2023, it is estimated that there will be 18,740 new cases of CLL, and an estimated 4,490 people will die of this disease. It represents 1.0% of all new cancer cases in the U.S. The rate of new cases was 4.6 per 100,000 men and women per year based on 2016-2020 cases, age-adjusted. Death rates from CLL are higher among older adults, or those 75 and older. The death rate was 1.1 per 100,000 men and women per year based on 2016-2020 deaths, age-adjusted. A common question that patients with CLL ask during their first clinic visit is: "How long will it be before I would need treatment?" Although this might seem like a simple question, the answer is not straight forward. CLL is a heterogenous disease, with a variable clinical course. Some patients may present with an aggressive disease requiring early initiation of treatment, while others have an indolent course and some, having so called smoldering CLL, may never need treatment. The variability in disease course can make predicting disease prognosis a complicated process. This brings forth the importance of establishing prognostic models that can predict disease course, time to treatment, and survival outcomes in such a heterogenous disease. The Rai and Binet staging systems were developed in the late 1970s to early 1980s. They separated patients into different stages based on clinical characteristics and laboratory findings. These simple staging systems are still in use; however, several prognostic markers need to be added for an individualized assessment and, with the recent development of genomic techniques leading to better understanding of CLL at the molecular level, newer prognostic markers have emerged.

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.

Cytogenomics of B-cell non-Hodgkin lymphomas: The "old" meets the "new"

For the routine diagnosis of haematological neoplasms an integrative approach is used considering the morphology, and the immunophenotypic, and molecular features of the tumor sample, along with clinical information. The identification and characterization of recurrent chromosomal aberrations mainly detected by conventional and molecular cytogenetics in the tumor cells has a major impact on the classification of lymphoid neoplasms. Some of the B-cell non-Hodgkin lymphomas are characterized by particular chromosomal aberrations, highlighting the relevance of conventional and molecular cytogenetic studies in their diagnosis and prognosis. In the current genomics era, next generation sequencing provides relevant information as the mutational profiles of haematological malignancies, improving their classification and also the clinical management of the patients. In addition, other new technologies have emerged recently, such as the optical genome mapping, which can overcome some of the limitations of conventional and molecular cytogenetics and may become more widely used in the cytogenetic laboratories in the upcoming years. Moreover, epigenetic alterations may complement genetic changes for a deeper understanding of the pathogenesis underlying B-cell neoplasms and a more precise risk-based patient stratification. Overall, here we describe the current state of the genomic data integrating chromosomal rearrangements, copy number alterations, and somatic variants, as well as a succinct overview of epigenomic changes, which altogether constitute a comprehensive diagnostic approach in B-cell non-Hodgkin lymphomas.

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.

High karyotypic complexity is an independent prognostic factor in patients with CLL treated with venetoclax combinations

Complex karyotypes have been associated with inferior outcomes in chronic lymphocytic leukemia (CLL) treated with chemoimmunotherapy (CIT), whereas their prognostic impact in the context of venetoclax-based treatments is still debated. In this prospective analysis on karyotype complexity in CLL, we evaluated the impact of complex (≥3 chromosomal aberrations [CAs], CKTs) and highly complex karyotypes (≥5 CAs; hCKTs) as well as specific aberrations in previously untreated patients without TP53 aberrations undergoing either CIT or time-limited venetoclax-based therapies in the phase 3 GAIA/CLL13 trial. Karyotype analyses were available for 895 of 926 patients (96.7%), of whom 153 (17%) had a CKT and 43 (5%) hCKT. In the CIT arm, CKT was associated with shorter progression-free survival (PFS) (hazard ratio [HR] 2.58; 95% confidence interval [95% CI], 1.54-4.32; P < .001) and overall survival (HR, 3.25; 95% CI, 1.03-10.26; P = .044). In the pooled venetoclax arms, a multivariable analysis identified hCKTs (HR, 1.96; 95% CI, 1.03-3.72; P = .041), but not CKTs, as independent adverse prognosticators for PFS. The presence of translocations (unbalanced and/or balanced) was also independently associated with shorter PFSs in the venetoclax arms. CIT led to the acquisition of additional CAs (mean CAs, 2.0-3.4; from baseline to CLL progression), whereas karyotype complexity remained stable after venetoclax-based treatments (2.0, both time points). This analysis establishes highly complex karyotypes and translocations as adverse prognostic factors in the context of venetoclax-based combination treatments. The findings of this study support the incorporation of karyotyping into the standard diagnostic workup of CLL, because it identifies patients at high risk of poor treatment outcomes and thereby improves prognostication. This trial was registered at www.clinicaltrials.gov as #NCT02950051.

Perspectives on the Application of Cytogenomic Approaches in Chronic Lymphocytic Leukaemia

Chronic lymphocytic leukaemia (CLL) is a haematological malignancy characterised by the accumulation of monoclonal mature B lymphocytes (positive for CD5+ and CD23+) in peripheral blood, bone marrow, and lymph nodes. Although CLL is reported to be rare in Asian countries compared to Western countries, the disease course is more aggressive in Asian countries than in their Western counterparts. It has been postulated that this is due to genetic variants between populations. Various cytogenomic methods, either of the traditional type (conventional cytogenetics or fluorescence in situ hybridisation (FISH)) or using more advanced technology such as DNA microarrays, next generation sequencing (NGS), or genome wide association studies (GWAS), were used to detect chromosomal aberrations in CLL. Up until now, conventional cytogenetic analysis remained the gold standard in diagnosing chromosomal abnormality in haematological malignancy including CLL, even though it is tedious and time-consuming. In concordance with technological advancement, DNA microarrays are gaining popularity among clinicians as they are faster and better able to accurately diagnose the presence of chromosomal abnormalities. However, every technology has challenges to overcome. In this review, CLL and its genetic abnormalities will be discussed, as well as the application of microarray technology as a diagnostic platform.

Clinical and economic burden of first-line chemoimmunotherapy by risk status in chronic lymphocytic leukemia

OBJECTIVES

To evaluate the trend in cytogenetic/molecular testing rate in chronic lymphocytic leukemia (CLL) and assess the clinical and economic burden of first-line (1 L) treatment with chemoimmunotherapy (CIT) by risk status.

METHODS

This retrospective cohort study identified patients with CLL from a U.S. managed care population. Medical records were obtained for eligible patients who initiated 1 L CIT between 1/1/2007 and 7/31/2019 and underwent prognostic testing to classify them as high risk (del(17p), TP53 mutation, del(11q), unmutated IGHV or complex karyotype) or as non-high risk by FISH only (non-del(17p) and non-del(11q)). Study outcomes included testing rate, time to next treatment (TTNT) or death, time to treatment failure (defined as time to change of therapy, non-chemotherapy intervention, hospice care or death), and total plan paid costs (medical + pharmacy) per patient per month (PPPM) in the 1 L period. Cox proportional hazard models and generalized linear models were used to calculate adjusted hazard ratio or rate ratio.

RESULTS

Among the 1,808 patients with CLL, 612 were FISH or IGHV tested and the rate of testing increased from 30% to 44% from 2007-2019. High-risk patients (n = 119) had 65% higher risk of next treatment or death (median time: 2.4 vs 3.7 years), 65% higher risk of treatment failure (median time: 3.0 vs 4.9 years), and 33% higher costs ($12,194 vs $9,055, p = 0.027) during 1 L treatment than non-high risk patients (n = 134).

CONCLUSIONS

High-risk CLL patients treated with 1 L chemoimmunotherapy have poorer clinical and economic outcomes compared to non-high risk patients. Assessment of genetic risk remains suboptimal.

Reinforced erythroid differentiation inhibits leukemogenic potential of t(8;21) leukemia

Oncoprotein AML1-ETO (AE) derived from t(8;21)(q22;q22) translocation is typically present in a portion of French-American-British-M2 subtype of acute myeloid leukemia (AML). Although these patients have relatively favorable prognoses, substantial numbers of them would relapse after conventional therapy. Here, we explored whether reinforcing the endogenous differentiation potential of t(8;21) AML cells would diminish the associated malignancy. In doing so, we noticed an expansion of immature erythroid blasts featured in both AML1-ETO9a (AE9a) and AE plus c-KIT (N822K) (AK) murine leukemic models. Interestingly, in the AE9a murine model, a spontaneous step-wise erythroid differentiation path, as characterized by the differential expression of CD43/c-Kit and the upregulation of several key erythroid transcription factors (TFs), accompanied the decline or loss of leukemia-initiating potential. Notably, overexpression of one of the key erythroid TFs, Ldb1, potently disrupted the repopulation of AE9a leukemic cells in vivo, suggesting a new promising intervention strategy of t(8;21) AML through enforcing their erythroid differentiation.

Five Percent Variant Allele Frequency Is a Reliable Reporting Threshold for TP53 Variants Detected by Next Generation Sequencing in Chronic Lymphocytic Leukemia in the Clinical Setting

The clinical significance of small TP53 clones detected with next generation sequencing (NGS) in chronic lymphocytic leukemia is an issue of active debate. According to the official guidelines, treatment decisions should be guided only by variants with variant allele frequency (VAF) ≥10%. We present data on 325 consecutive patients with chronic lymphocytic leukemia analyzed with NGS. In total 47 pathogenic/likely pathogenic (P/LP), TP53 variants were detected in 26 patients (8%). Eleven of these (23%) were in the 5% to 10% VAF range and reported according to our institutional policy. All TP53 variants in the 5% to 10% VAF range were confirmed (100% concordance) with a second NGS panel. Our results where further validated with the performance of Sanger sequencing and digital droplet PCR (ddPCR). In 12 patients with available fluorescence in situ hybridization data and TP53 mutations within 5% to 10% VAF, deletion of chromosome 17p (del(17p)) was detectable in only 1 patient. We propose a robust diagnostic algorithm, which allows the safe detection and reporting of TP53 variants with VAF down to 5% in the clinical setting. Our study provides evidence that NGS is equally potent to detect variants with VAF 5% to 10% compared to those with VAF 10% to 15%, highlighting the urgent need for harmonization of NGS methodologies across diagnostic laboratories.

Cytogenetics in Chronic Lymphocytic Leukemia: ERIC Perspectives and Recommendations

Mounting evidence underscores the clinical value of cytogenetic analysis in chronic lymphocytic leukemia (CLL), particularly as it allows the identification of complex karyotype, that has recently emerged as a prognostic and potentially predictive biomarker. That said, explicit recommendations regarding the methodology and clinical interpretation of either chromosome banding analysis (CBA) or chromosome microarray analysis (CMA) are still lacking. We herein present the consensus of the Cytogenetic Steering Scientific Committee of ERIC, the European Research Initiative on CLL, regarding methodological issues as well as clinical interpretation of CBA/CMA and discuss their relevance in CLL. ERIC considers CBA standardized and feasible for CLL on the condition that standards are met, extending from the use of novel mitogens to the accurate interpretation of the findings. On the other hand, CMA, is also standardized, however, robust data on its clinical utility are still scarce. In conclusion, cytogenetic analysis is not yet mature enough to guide treatment choices in CLL. That notwithstanding, ERIC encourages the wide application of CBA, and potentially also CMA, in clinical trials in order to obtain robust evidence regarding the predictive value of specific cytogenetic profiles towards refining risk stratification and improving the management of patients with CLL.

Chromosome banding analysis and genomic microarrays are both useful but not equivalent methods for genomic complexity risk stratification in chronic lymphocytic leukemia patients

Genome complexity has been associated with poor outcome in patients with chronic lymphocytic leukemia (CLL). Previous cooperative studies established five abnormalities as the cut-off that best predicts an adverse evolution by chromosome banding analysis (CBA) and genomic microarrays (GM). However, data comparing risk stratification by both methods are scarce. Herein, we assessed a cohort of 340 untreated CLL patients highly enriched in cases with complex karyotype (CK) (46.5%) with parallel CBA and GM studies. Abnormalities found by both techniques were compared. Prognostic stratification in three risk groups based on genomic complexity (0-2, 3- 4 and ≥5 abnormalities) was also analyzed. No significant differences in the percentage of patients in each group were detected, but only a moderate agreement was observed between methods when focusing on individual cases (κ=0.507; P<0.001). Discordant classification was obtained in 100 patients (29.4%), including 3% classified in opposite risk groups. Most discrepancies were technique-dependent and no greater correlation in the number of abnormalities was achieved when different filtering strategies were applied for GM. Nonetheless, both methods showed a similar concordance index for prediction of time to first treatment (TTFT) (CBA: 0.67 vs. GM: 0.65) and overall survival (CBA: 0.55 vs. GM: 0.57). High complexity maintained its significance in the multivariate analysis for TTFT including TP53 and IGHV status when defined by CBA (hazard ratio [HR] 3.23; P<0.001) and GM (HR 2.74; P<0.001). Our findings suggest that both methods are useful but not equivalent for risk stratification of CLL patients. Validation studies are needed to establish the prognostic value of genome complexity based on GM data in future prospective studies.

Treatment Approaches to Chronic Lymphocytic Leukemia With High-Risk Molecular Features

The clinical course of chronic lymphocytic leukemia (CLL) is highly variable. Over the past decades, several cytogenetic, immunogenetic and molecular features have emerged that identify patients suffering from CLL with high-risk molecular features. These biomarkers can clearly aid prognostication, but may also be capable of predicting the efficacy of various treatment strategies in subgroups of patients. In this narrative review, we discuss treatment approaches to CLL with high-risk molecular features. Specifically, we review and provide a comprehensive overview of clinical trials evaluating the efficacy of chemotherapy, chemoimmunotherapy and novel agent-based treatments in CLL patients with TP53 aberrations, deletion of the long arm of chromosome 11, complex karyotype, unmutated IGHV, B cell receptor stereotypy, and mutations in NOTCH1 or BIRC3. Furthermore, we discuss future pharmaceutical and immunotherapeutic perspectives for CLL with high-risk molecular features, focusing on agents currently under investigation in clinical trials.

Biology and Treatment of High-Risk CLL: Significance of Complex Karyotype

Several reports highlight the clinical significance of cytogenetic complexity, namely, complex karyotype (CK) identified though the performance of chromosome banding analysis (CBA) in chronic lymphocytic leukemia. Indeed, apart from a number of studies underscoring the prognostic and predictive value of CK in the chemo(immune)therapy era, mounting evidence suggests that CK could serve as an independent prognosticator and predictor even in patients treated with novel agents. In the present review, we provide an overview of the current knowledge regarding the clinical impact of CK in CLL, touching upon open issues related to the incorporation of CK in the clinical setting.

Cytogenetic and molecular abnormalities in Waldenström's macroglobulinemia patients: Correlations and prognostic impact

While Waldenström macroglobulinemia (WM) is characterized by an almost unifying mutation in MYD88, clinical presentation at diagnosis and response to therapy can be widely different among WM patients. Current prognostic tools only partially address this clinical heterogeneity. Limited data compiling both molecular and cytogenetic information have been used in risk prognostication in WM. To investigate the clinical impact of genetic alterations in WM, we evaluated cytogenetic and molecular abnormalities by chromosome banding analyses, FISH and targeted NGS in a retrospective cohort of 239 WM patients, including 187 patients treated by first-line chemotherapy or immunochemotherapy. Most frequent mutations were identified in MYD88 (93%), CXCR4 (29%), MLL2 (11%), ARID1A (8%), TP53 (8%), CD79A/B (6%), TBL1XR1 (4%) and SPI1 (4%). The median number of cytogenetic abnormalities was two (range, 0-22). Main cytogenetic abnormalities were 6q deletion (del6q) (27%), trisomy 4 (tri4) (12%), tri18 (11%), del13q (11%), tri12 (7.5%) and del17p (7%). Complex karyotype (CK) was observed in 15% (n = 31) of cases, including 5% (n = 12) of highly CK (high-CK). TP53 abnormalities (TP53abn) were present in 15% of evaluable patients. TP53abn and del6q were associated with CK/high-CK (p < .05). Fifty-three percent of patients with hyperviscosity harbored CXCR4 mutations. Cytogenetic and molecular abnormalities did not significantly impact time to first treatment and response to therapy. Prognostic factors associated with shorter PFS were del6q (p = .01), TP53abn (p = .002) and high-CK (p = .01). These same factors as well as IPSSWM, tri4, CXCR4 frameshift and SPI1 mutations were significantly associated with lower OS (p < .05). These results argue for integration of both cytogenetic and molecular screening in evaluation of first-line WM patients.

Balanced and unbalanced translocations in a multicentric series of 2843 patients with chronic lymphocytic leukemia

Chromosomal translocations in chronic lymphocytic leukemia (CLL) are very rare, and therefore systematic analysis of large series of cases is needed to allow the identification of recurrent rearrangements, breakpoints involved, and target genes. The aims of the present study were to identify new translocations and their clinical impact and to establish their frequency in a large cohort of 2843 CLL patients. By conventional cytogenetics 250 translocations were identified in 215 (7.5%) patients, 186 (74%) were apparently balanced and 64 (26%) were unbalanced. All chromosomes were involved in translocations, except Y chromosome. The chromosomes more frequently translocated were in decreasing frequency chromosomes 14, 18, 13, 17, 1, 6, 2, 3, 8, and 11. Translocations were found in the karyotypes either as the unique chromosomal abnormality (27%), associated with another alteration (24%), or as a part of a complex karyotype (CK, 48%). A large proportion of rearranged breakpoints involved genes related to CLL such as IGH (14q32), RB1, MIR15A, MIR16-1 (13q14), BCL2 (18q21), IGL (22q11.2), TP53 (17p13), IRF4 (6p25-p23), ATM (11q22), and CDK6 (7q21). Overall, 76 novel CLL translocations were identified, including a recurrent t(8;11)(p21;q21-23). Whole-genome sequencing and/or copy-number microarray data of 24 cases with translocations confirmed all rearrangements, enabled refinement of 3 karyotypes and all breakpoints at gene level. The projected survival and time to first treatment significantly decreased linearly with the number of translocations. In summary, this study allowed to establish the frequency of translocations (7.5%) and to identify new translocations in a cohort of 2843 CLL patients.

[Chronic lymphocytic leukemia with t (14;18) (q32;q21) : report of eight cases and a literature review]

目的

分析伴t(14;18)(q32;q21)的慢性淋巴细胞白血病（CLL）患者的临床特征及预后，并进行相关文献复习。

方法

收集并分析2009年11月至2019年11月于江苏省人民医院就诊的8例伴t(14;18)(q32;q21)的CLL患者的临床资料。

结果

8例患者中7例男性，1例女性，诊断时中位年龄70岁，3例免疫表型积分5分，4例积分4分，1例积分3分。所有患者的骨髓组织病理学均为典型CLL表现。染色体核型示所有患者的t(14;18)(q32;q21)均为干系，3例仅携带t(14;18)(q32;q21)异常，4例为t(14;18)(q32;q21)伴+12，1例为t(14;18)(q32;q21)伴13q−。通过FISH在另外3例患者中发现了13q−。6例检测了免疫球蛋白重链可变区（IGHV）突变状态且均为有突变，未见IGHV3-21片段使用。进行相关检测的患者中，仅1例携带TP53突变，其余患者未见TP53、SF3B1、NOTCH1、MYD88突变。中位随访30.9个月时，1例死亡，7例存活，其中3例尚未达到治疗指征，4例接受化疗或免疫治疗的患者病情均稳定。

结论

t(14;18)(q32;q21)在CLL中少见，往往与+12、有突变的IGHV伴随出现。伴t(14;18)(q32;q21)的CLL可能预后良好。

Prognostic significance of translocations in the presence of mutated IGHV and of cytogenetic complexity at diagnosis of chronic lymphocytic leukemia

Mutations of the IGH variable region in patients with chronic lymphocytic leukemia (CLL) are associated with a favorable prognosis. Cytogenetic complexity (>3 unrelated aberrations) and translocations have been associated with an unfavorable prognosis. While mutational status of IGHV is stable, cytogenetic aberrations frequently evolve. However, the relationships of these features as prognosticators at diagnosis are unknown. We examined the CpG-stimulated metaphase cytogenetic features detected within one year of diagnosis of CLL and correlated these features with outcome and other clinical features including IGHV. Of 329 untreated patients, 53 (16.1%) had a complex karyotype (16.1%), and 85 (25.8%) had a translocation. Median time to first treatment (TFT) was 47 months. In univariable analyses, significant risk factors for shorter TFT (p3.5, log-transformed WBC, unmutated IGHV, complex karyotype, translocation, and FISH for trisomy 8, del(11q) and del(17p). In multivariable analysis, there was significant effect modification of IGHV status on the relationship between translocation and TFT (p=0.002). In IGHV mutated patients, those with a translocation had over 3.5 times higher risk of starting treatment than those without a translocation (p.

Prognostic and Predictive Implications of Cytogenetics and Genomics

Chronic lymphocytic leukemia (CLL) is characterized by extreme genomic heterogeneity. Numerous recurrent genetic abnormalities are associated with dismal clinical outcome in patients treated with chemo(immuno)therapy, with aberrations of the TP53 gene being the main genomic abnormalities that dictate treatment choice. In the era of novel agents the predictive significance of the genomic aberrations is highly challenged as the results of the clinical trials performed thus far question the previously established unfavorable impact of genomic aberrations, even that of the TP53 gene. The prognostic and predictive value of the most common genomic abnormalities is discussed in the present review.

From Biomarkers to Models in the Changing Landscape of Chronic Lymphocytic Leukemia: Evolve or Become Extinct

Simple Summary

Chronic lymphocytic leukemia (CLL) is characterized by a highly variable clinical course. Thus, predicting the outcome of patients with this disease is a topic of special interest. The rapidly changing treatment landscape of CLL has questioned the value of classical biomarkers and prognostic models. Herein we examine the current state-of-the-art of prognostic and predictive biomarkers in the setting of new oral targeted agents with special focus on the most controversial findings over the last years. We also discuss the available information on the role of “old” and “new” prognostic models in the era of oral small molecules.

Abstract

Chronic lymphocytic leukemia (CLL) is an extremely heterogeneous disease. With the advent of oral targeted agents (Tas) the treatment of CLL has undergone a revolution, which has been accompanied by an improvement in patient’s survival and quality of life. This paradigm shift also affects the value of prognostic and predictive biomarkers and prognostic models, most of them inherited from the chemoimmunotherapy era but with a different behavior with Tas. This review discusses: (i) the role of the most relevant prognostic and predictive biomarkers in the setting of Tas; and (ii) the validity of classic and new scoring systems in the context of Tas. In addition, a critical point of view about predictive biomarkers with special emphasis on 11q deletion, novel resistance mutations, TP53 abnormalities, IGHV mutational status, complex karyotype and NOTCH1 mutations is stated. We also go over prognostic models in early stage CLL such as IPS-E. Finally, we provide an overview of the applicability of the CLL-IPI for patients treated with Tas, as well as the emergence of new models, generated with data from patients treated with Tas.

Incorporating molecular biomarkers into the continuum of care in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is a mature B-cell malignancy characterized by marked heterogeneity. Discoveries in disease biology over the past two decades have helped explain clinical variability and heralded the arrival of the targeted therapy era. In this article, we review improvements in risk stratification which have coincided with this progress, including individual biomarkers and their incorporation into prognostic models. Amidst an ever-expanding list of biomarkers, we seek to bring focus to the essential tests to improve patient care and counseling at particular times in the disease course, beginning with prognosis at diagnosis. The majority of patients do not require treatment at the time of diagnosis, making time-to-first-treatment a key initial prognostic concern. Prognostic and predictive biomarkers are then considered at subsequent major junctures, including at the time of treatment initiation, while on therapy, and at the time of relapse on novel agents.

Genomic arrays identify high-risk chronic lymphocytic leukemia with genomic complexity: a multi-center study

Complex karyotype (CK) identified by chromosome-banding analysis (CBA) has shown prognostic value in chronic lymphocytic leukemia (CLL). Genomic arrays offer high-resolution genome-wide detection of copy-number alterations (CNAs) and could therefore be well equipped to detect the presence of a CK. Current knowledge on genomic arrays in CLL is based on outcomes of single center studies, in which different cutoffs for CNA calling were used. To further determine the clinical utility of genomic arrays for CNA assessment in CLL diagnostics, we retrospectively analyzed 2293 arrays from 13 diagnostic laboratories according to established standards. CNAs were found outside regions captured by CLL FISH probes in 34% of patients, and several of them including gains of 8q, deletions of 9p and 18p (p<0.01) were linked to poor outcome after correction for multiple testing. Patients (n=972) could be divided in three distinct prognostic subgroups based on the number of CNAs. Only high genomic complexity (high-GC), defined as ≥5 CNAs emerged as an independent adverse prognosticator on multivariable analysis for time to first treatment (Hazard ratio: 2.15, 95% CI: 1.36-3.41; p=0.001) and overall survival (Hazard ratio: 2.54, 95% CI: 1.54-4.17; p<0.001; n=528). Lowering the size cutoff to 1 Mb in 647 patients did not significantly improve risk assessment. Genomic arrays detected more chromosomal abnormalities and performed at least as well in terms of risk stratification compared to simultaneous chromosome banding analysis as determined in 122 patients. Our findings highlight genomic array as an accurate tool for CLL risk stratification.

The complex karyotype and chronic lymphocytic leukemia: prognostic value and diagnostic recommendations

Chromosomal abnormalities are frequently observed in patients with chronic lymphocytic leukemia (CLL) and have prognostic value. Deletions of the short arm of chromosome 17 (and/or mutations TP53) predict resistance to chemoimmunotherapy and shorter progression-free survival after targeted therapies. Although the complex karyotype (CK) is strongly predictive of a poor prognosis in hematologic malignancies such acute myeloid leukemia or myelodysplastic syndrome, its value in CLL is subject to debate. Here, we review the literature on the CK in CLL and examine its prognostic value with different treatments. We also propose a standardized method for defining a CK in all types of hematopoietic neoplasm.

Harrison C, Eswaran J, Soundararajan M. DAP Kinase-Related Apoptosis-Inducing Protein Kinase 2 (DRAK2) Is a Key Regulator and Molecular Marker in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in the Western World and it is characterized by a marked degree of clinical heterogeneity. An impaired balance between pro- and anti-apoptotic stimuli determines chemorefractoriness and outcome. The low proliferation rate of CLL cells indicates that one of the primary mechanisms involved in disease development may be an apoptotic failure. Here, we study the clinical and functional significance of DRAK2, a novel stress response kinase that plays a critical role in apoptosis, T-cell biology, and B-cell activation in CLL. We have analyzed CLL patient samples and showed that low expression levels of DRAK2 were significantly associated with unfavorable outcome in our CLL cohort. DRAK2 expression levels showed a positive correlation with the expression of DAPK1, and TGFBR1. Consistent with clinical data, the downregulation of DRAK2 in MEC-1 CLL cells strongly increased cell viability and proliferation. Further, our transcriptome data from MEC-1 cells highlighted MAPK, NF-κB, and Akt and as critical signaling hubs upon DRAK2 knockdown. Taken together, our results indicate DRAK2 as a novel marker of CLL survival that plays key regulatory roles in CLL prognosis.

SOHO State of the Art Updates and Next Questions: Clonal Evolution in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is an indolent disease with a long-lasting clinical course, with indication for treatment only when symptomatic. Its clinical heterogeneity is widely reported, with some patients requiring treatment soon after diagnosis because of development of cytopenia or bulky lymphadenopathy, and others showing a stable or a slowly progressive disease not requiring treatment for decades. Longitudinal sampling of peripheral blood, with accessible tumor cells and circulating tumor DNA, enabled the analysis of disease growing dynamics and the characterization of clonal evolution. Here we describe the main known features of CLL genomics and its shaping upon treatment, which can lead to progression, treatment refractoriness, or transformation into an aggressive lymphoma.

Recent progress of prognostic biomarkers and risk scoring systems in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia with high heterogeneity in the western world. Thus, investigators identified a number of prognostic biomarkers and scoring systems to guide treatment decisions and validated them in the context of immunochemotherapy. A better understanding of prognostic biomarkers, including serum markers, flow cytometry outcomes, IGHV mutation status, microRNAs, chromosome aberrations and gene mutations, have contributed to prognosis in CLL. Del17p/ TP53 mutation, NOTCH1 mutation, CD49d, IGHV mutation status, complex karyotypes and microRNAs were reported to be of predictive values to guide clinical decisions. Based on the biomarkers above, classic prognostic models, such as the Rai and Binet staging systems, MDACC nomogram, GCLLSG model and CLL-IPI, were developed to improve risk stratification and tailor treatment intensity. Considering the presence of novel agents, many investigators validated the conventional prognostic biomarkers in the setting of novel agents and only TP53 mutation status/del 17p and CD49d expression were reported to be of prognostic value. Whether other prognostic indicators and models can be used in the context of novel agents, further studies are required.

Chronic lymphocytic leukemia: from molecular pathogenesis to novel therapeutic strategies

Chronic lymphocytic leukemia is a well-defined lymphoid neoplasm with very heterogeneous biological and clinical behavior. The last decade has been remarkably fruitful in novel findings elucidating multiple aspects of the pathogenesis of the disease including mechanisms of genetic susceptibility, insights into the relevance of immunogenetic factors driving the disease, profiling of genomic alterations, epigenetic subtypes, global epigenomic tumor cell reprogramming, modulation of tumor cell and microenvironment interactions, and dynamics of clonal evolution from early steps in monoclonal B cell lymphocytosis to progression and transformation into diffuse large B-cell lymphoma. All this knowledge has offered new perspectives that are being exploited therapeutically with novel target agents and management strategies. In this review we provide an overview of these novel advances and highlight questions and perspectives that need further progress to translate into the clinics the biological knowledge and improve the outcome of the patients.

In chronic lymphocytic leukaemia, SLAMF1 deregulation is associated with genomic complexity and independently predicts a worse outcome

In a series of 349 patients with chronic lymphocytic leukaemia (CLL), we found lower levels of signalling lymphocytic activation molecule family member 1 (SLAMF1) expression in cases with highly complex karyotypes, as defined by the presence of five or more chromosomal abnormalities (CK5; P < 0·001) and with major chromosomal structural abnormalities (P < 0·001). SLAMF1 downregulation was significantly associated with advanced Binet Stage (P = 0·001), CD38 positivity (P < 0·001), high β₂ -microglobulin levels (P < 0·001), immunoglobulin heavy chain variable region gene (IGHV) unmutated status (P < 0·001), 11q deletion (P < 0·001), tumour protein p53 (TP53) disruption (P = 0·011) and higher risk CLL International Prognostic Index categories (P < 0·001). Multivariate analysis showed that downregulated SLAMF1 levels had independent negative prognostic impact on time-to-first treatment (P < 0·001) and overall survival (P < 0·001).

Genomic and Epigenomic Alterations in Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia is a common disease in Western countries and has heterogeneous clinical behavior. The relevance of the genetic basis of the disease has come to the forefront recently, with genome-wide studies that have provided a comprehensive view of structural variants, somatic mutations, and different layers of epigenetic changes. The mutational landscape is characterized by relatively common copy number alterations, a few mutated genes occurring in 10-15% of cases, and a large number of genes mutated in a small number of cases. The epigenomic profile has revealed a marked reprogramming of regulatory regions in tumor cells compared with normal B cells. All of these alterations are differentially distributed in clinical and biological subsets of the disease, indicating that they may underlie the heterogeneous evolution of the disease. These global studies are revealing the molecular complexity of chronic lymphocytic leukemia and provide new perspectives that have helped to understand its pathogenic mechanisms and improve the clinical management of patients.

An Updated Perspective on Current Prognostic and Predictive Biomarkers in Chronic Lymphocytic Leukemia in the Context of Chemoimmunotherapy and Novel Targeted Therapy

Chronic lymphocytic leukemia (CLL) is a heterogeneous disease with a variable clinical course. Novel biomarkers discovered over the past 20 years have revolutionized the way clinicians approach prognostication and treatment especially in the chemotherapy-free era. Herein, we review the best established prognostic and predictive biomarkers in the setting of chemoimmunotherapy (CIT) and novel targeted therapy. We propose that TP53 disruption (defined as either TP53 mutation or chromosome 17p deletion), unmutated immunoglobulin heavy chain variable region gene status (UM IGHV), NOTCH1 mutation, and CD49d expression are the strongest prognosticators of disease progression and overall survival in the field of novel biomarkers including recurrent gene mutations. We also highlight the predictive role of TP53 disruption, UM IGHV, and NOTCH1 mutation in the setting of CIT and TP53 disruption and CD49d expression in the setting of novel targeted therapy employing B-cell receptor (BCR) and B-cell lymphoma-2 (BCL2) inhibition. Finally, we discuss future directions in the field of biomarker development to identify those with relapsed/refractory disease at risk for progression despite treatment with novel therapies.

[Chromosomal aberrations detection in chronic lymphocytic leukemia by conventional cytogenetics using DSP30 and IL-2]

Objective: To study the value of unmethylated cytosine guanine dinucleotide oligodeoxynucleotide (DSP30) and IL-2 in the conventional cytogenetic (CA) detection of the chromosomal aberrations in chronic lymphocytic leukemia (CLL) . Methods: Bone marrow or peripheral blood cells of CLL patients were cultured with DSP30 plus IL-2 for 72 h, following which R-banding analysis was conducted. Fluorescence in situ hybridization (FISH) was performed in 85 patients. CA results were compared with data obtained by FISH. Results: Among 89 CLL patients, the success rate of chromosome analysis was 94.38% (84/89) . Clonal aberrations were detected in 51 patients (51/84, 60.71%) . Of them, 27 (27/51, 52.94%) were complex karyotype. Among 85 CLL patients tested by FISH, chromosomal abnormalities were detected in 74 (74/85, 87.06%) patients, of which 2 (2/74) patients were complex karyotypes, accounting for 2.70%. Of the 85 CLL patients examined by FISH, 50 had abnormal karyotype analysis, 30 had normal karyotype, 5 failed to have chromosome analysis. Among them, 25 cases showed clonal aberrations by FISH assay but normal by CA, and 4 cases were normal by FISH but displayed aberrations in chromosome analysis, and totally 78 (91.76%) cases with abnormality detected by the combination of the two methods. The frequency of 13q- abnormality detected by FISH was significantly higher than that by CA analysis (69.41%vs 16.67%, P<0.001) , while the frequency of 11q-,+12 and 17p- detected by two methods showed no significant difference (P>0.05) . The detection rate of complex abnormalities in conventional karyotype analysis was higher than that in FISH (50.98%vs 2.70%) . In addition, 11 low-risk and 9 intermediate-risk patients according to FISH results showed complex karyotype by cytogenetics, and were classified into high-risk cytogenetic subgroup. Conclusion: DSP30 and IL-2 are effective in improving the detection rate of CA in CLL patients (60.71%) and CA is more effective to detect complex karyotype. However, FISH had a higher overall abnormality detection rate (87.06%) than CA, especially for 13q-. The combination of CA and FISH not only enhanced the detection rate of clonal aberrations to 91.76%, but also provided more precise prognosis stratification for CLL patients, thus to provide more information for clinical implication.

Treatment-naive CLL: lessons from phase 2 and phase 3 clinical trials

The management of chronic lymphocytic leukemia (CLL) has undergone dramatic changes over the previous 2 decades with the introduction of multiple new therapies and new combinations. Management of the newly diagnosed asymptomatic patient has not significantly changed outside of the development of a number of prognostic factors and the CLL International Prognostic Index, which is helpful in discussions regarding prognosis and likelihood of requiring treatment. When therapy is required, initial treatment of most patients now includes either the Bruton tyrosine kinase inhibitor ibrutinib or the B-cell lymphoma 2 inhibitor venetoclax in combination with obinutuzumab. Current frontline trials are focused on the optimal sequencing or combination of targeted therapies. In this review, we will discuss the management of previously untreated CLL with an emphasis on the clinical trials that have formed the standard of care, as well as those newer studies that are likely to form the next generation of therapy.

Treatment-naive CLL: lessons from phase 2 and phase 3 clinical trials

The management of chronic lymphocytic leukemia (CLL) has undergone dramatic changes over the previous 2 decades with the introduction of multiple new therapies and new combinations. Management of the newly diagnosed asymptomatic patient has not significantly changed outside of the development of a number of prognostic factors and the CLL International Prognostic Index, which is helpful in discussions regarding prognosis and likelihood of requiring treatment. When therapy is required, initial treatment of most patients now includes either the Bruton tyrosine kinase inhibitor ibrutinib or the B-cell lymphoma 2 inhibitor venetoclax in combination with obinutuzumab. Current frontline trials are focused on the optimal sequencing or combination of targeted therapies. In this review, we will discuss the management of previously untreated CLL with an emphasis on the clinical trials that have formed the standard of care, as well as those newer studies that are likely to form the next generation of therapy.

Profiling of biological and environmental risk factors in immunogenetic subgroups of chronic lymphocytic leukemia - Czech national study

AIMS

This is a nation-wide survey of chronic lymphocytic leukemia (CLL) patients at six large hematology centers in the Czech Republic. The aim was to identify specific populations, social, and health characteristics of CLL subgroups divided according to the immunogenetic features of their B cell receptors (BCRs) and clonality.

PATIENTS AND METHODS

Questionnaires directed to specific health, social, and environmental conditions were collected in a cohort of 573 CLL patients. For these patients, immunoglobulin heavy chain gene rearrangements were also analyzed in order to gain information about their clonality, IGHV mutational status, and the presence of stereotyped BCRs. Data extracted from the questionnaires were analyzed statistically in the context of immunogenetic features of the cohort.

RESULTS

There were no statistically significant differences in the data collected in the survey between patients with mutated and patients with unmutated IGHV. However, patients with oligoclonal CLL reported health conditions such as hypercholesterolemia, hypertension, herpes simplex, tumors, and also, separately, CLL in 1^st degree relatives, more often than their monoclonal counterparts. In patients with stereotyped BCRs, we found more frequent alcohol consumption and gastric infections in subset #1 cases and frequent cholecystectomies and familial CLL in subset #2 cases.

CONCLUSION

To the best of our knowledge, this study is the first to investigate CLL immunogenetic features and clonality in the context of epidemiological data. We reported statistically significant associations suggesting the influence of certain health and social conditions on a number of clonal populations expanding in CLL and also on characteristic BCR features, especially stereotypy.

Analysis of basal chromosome instability in patients with chronic lymphocytic leukaemia

Genomic instability is a hallmark of cancer, contributing to tumour development and transformation, being chromosome instability (CIN) the most common form in human cancer. Chronic lymphocytic leukaemia (CLL) is the most frequent adult leukaemia in the Western world. In this study, we have evaluated basal CIN in untreated patients with CLL by measuring chromosome aberrations (CAs) and micronucleus (MN) frequency and their association with different prognostic factors. Seventy-two patients and 21 normal controls were analysed. Cytogenetic and fluorescence in situ hybridisation (FISH) studies were performed. IGHV (immunoglobulin heavy chain variable region) mutational status was evaluated by reverse transcription polymerase chain reaction and sequencing. An increased number of CA in patients compared with controls (P = 0.0001) was observed. Cases with abnormal karyotypes showed increased CA rate than those with normal karyotypes (P = 0.0026), with a particularly highest frequency in cases with complex karyotypes. Among FISH risk groups, a significant low frequency of CA was found in patients with no FISH alterations compared to those with del13q14 and ≥2 FISH alterations (P = 0.0074). When mean CA value (6.7%) was considered, significant differences in the distribution of low and high CA frequency between cases with normal and abnormal karyotypes (P = 0.002) were observed. By MN analysis, higher frequency in patients compared to controls (P = 0.0001) was also found, as well as between cases with ≥2 FISH abnormalities and those with no FISH alterations (P = 0.026). Similarly, significant differences were observed when patients were divided according to mean MN frequency (2.2%; P ≤ 0.04). Interestingly, patients with high MN frequency had shorter time to first treatment than those with low frequency (P = 0.024). Cases with mutated and unmutated IGHV status showed increased CA and MN frequencies compared to controls (P ≤ 0.0007), but no differences between both groups were found. Our results support the strong interaction between CIN and genomic complexity as well as their influence on poor outcome in this pathology.

Complex karyotype as a predictor of high-risk chronic lymphocytic leukemia: A single center experience over 12 years

OBJECTIVES

A complex karyotype (CK) is considered a poor prognostic marker in chronic lymphocytic leukemia (CLL).

METHODS

The study analyzed 644 untreated CLL patients (pts) using conventional/molecular cytogenetics to reveal the presence of a CK and its composition and to assess its predictive value. The mutational status ofTP53 was detected by next generation sequencing.

RESULTS

A CK was detected in 79 pts (12.3%). Patients with a CK showed shorter overall survival (OS) compared to those without a CK (77 months vs. 115 months, p < 0.0001). Chromosomes most frequently included in a CK were 13, 11, 17, 8, 2, and 6. The most common aberrations in a CK were translocations, numerical changes and dicentric chromosomes (with no effect on OS). Patients with aberrations ofTP53 and ATM were shown to have adverse prognosis comparable to patients with a CK without these abnormalities. A stronger impact of a CK on OS of female and older CLL patients was observed.

CONCLUSIONS

The determining of the presence of a CK is essential in modern clinical CLL practice. According to recent studies, the presence of a CK affects clinical and treatment decision-making.

Derivatisation of parthenolide to address chemoresistant chronic lymphocytic leukaemia

Parthenolide is a natural product that exhibits anti-leukaemic activity, however, its clinical use is limited by its poor bioavailability. It may be extracted from feverfew and protocols for growing, extracting and derivatising it are reported. A novel parthenolide derivative with good bioavailability and pharmacological properties was identified through a screening cascade based on in vitro anti-leukaemic activity and calculated "drug-likeness" properties, in vitro and in vivo pharmacokinetics studies and hERG liability testing. In vitro studies showed the most promising derivative to have comparable anti-leukaemic activity to DMAPT, a previously described parthenolide derivative. The newly identified compound was shown to have pro-oxidant activity and in silico molecular docking studies indicate a prodrug mode of action. A synthesis scheme is presented for the production of amine 7 used in the generation of 5f.

The combination of complex karyotype subtypes and IGHV mutational status identifies new prognostic and predictive groups in chronic lymphocytic leukaemia

BACKGROUND

Complex karyotype (CK) is a heterogeneous category with a negative impact in chronic lymphocytic leukaemia (CLL). Our group has recently reported that CK patients with major structural abnormalities (i.e. CK2) are characterised by a worse prognosis, as compared to other lesions within CK(CK1).

METHODS

We performed a multicentre retrospective study to test whether the combination of CK subtypes with IGHV status could be a relevant prognostic and predictive tool.

RESULTS

Among 522 patients 13% harboured CK2, 41% CK1 and/or U-IGHV (U-CK1) and 46% M-IGHV without any CK subtypes (M-noCK). After a median follow-up of 5.8 years, CK2 patients had the shortest TTFT (5-year TTFT 31%, 39 and 81%, p < 0.0001) and OS (5-year OS 67%, 85 and 93%, p < 0.0001) as compared to U-CK1 or M-noCK cases, regardless of TP53 abnormalities. CK2 patients also had the worst outcome after chemoimmunotherapy. In fact, the median TTNT after FCR or BR was 1.86 and 4.79 years for CK2 and U-CK1, but not reached for M-noCK patients (p < 0.0005).

CONCLUSIONS

We herein suggest that the combined assessment of the IGHV mutational status and CK subtypes refines the prognostication of CLL, allowing to identify M-IGHV patients without any CK subtypes who are characterised by an indolent disease and excellent outcome after chemoimmunotherapy.

Culture and Harvest of CpG-Stimulated Peripheral Blood or Bone Marrow in Chronic Lymphocytic Leukemia

Chromosome analysis of chronic lymphocytic leukemia (CLL) is an important clinical tool for evaluating prognosis and disease progression. Visualizing chromosomes microscopically using traditional cytogenetic techniques requires dividing cells to be arrested during metaphase. The major challenge for performing this analysis on CLL samples is stimulating the cells to divide in culture. Stimulation of CLL cells with CpG oligodeoxynucleotides has improved our ability to perform chromosome analysis for this leukemia. This protocol should help the reader successfully culture CLL samples for clinical chromosome analysis.

Gain of the short arm of chromosome 2 (2p gain) has a significant role in drug-resistant chronic lymphocytic leukemia

The different types of drug resistance encountered in chronic lymphocytic leukemia (CLL) cannot be fully accounted for by the 17p deletion (and/or TP53 mutation), a complex karyotype (CK), immunoglobulin heavy‐chain variable region genes (IGHV) status and gene mutations. Hence, we sought to assess the associations between recurrent genomic abnormalities in CLL and the disease's development and outcome. To this end, we analyzed 64 samples from patients with CLL and gain of the short arm of chromosome 2 (2p+), which is frequent in late‐stage and relapsed/refractory CLL. We found that fludarabine/cyclophosphamide/rituximab (a common first‐line treatment in CLL) is not effective in removing the 2p+ clone ‐ even in samples lacking a CK, the 17p deletion or unmutated IGHV. Our results suggest strongly that patients with CLL should be screened for 2p+ (using karyotyping and fluorescence in situ hybridization) before a treatment option is chosen. Longer follow‐up is now required to evaluate bendamustine‐rituximab, ibrutinib, and idelalisib‐rituximab treatments.

Improving risk-stratification of patients with chronic lymphocytic leukemia using multivariate patient similarity networks

BACKGROUND

Better risk-stratification of patients with chronic lymphocytic leukemia (CLL) and identification of subsets of ultra-high-risk (HR)-CLL patients are crucial in the contemporary era of an expanded therapeutic armamentarium for CLL.

METHODS

A multivariate patient similarity network and clustering was applied to assess the prognostic values of routine genetic, laboratory, and clinical factors and to identify subsets of ultra-HR-CLL patients. The study cohort consisted of 116 HR-CLL patients (F/M 36/80, median age 63 yrs) carrying del(11q), del(17p)/TP53 mutations and/or complex karyotype (CK) at the time of diagnosis.

RESULTS

Three major subsets based on the presence of key prognostic variables as genetic aberrations, bulky lymphadenopathy, splenomegaly, and gender: profile (P)-I (n = 34, men/women with CK + no del(17p)/TP53 mutations), P-II (n = 47, predominantly men with del(11q) + no CK + no del(17p)/TP53 mutations), and P-III (n = 35, men/women with del(17p)/TP53 mutations, with/without del(11q) and CK) were revealed. Subanalysis of major subsets identified three ultra-HR-CLL groups: men with TP53 disruption with/without CK, women with TP53 disruption with CK and men/women with CK + del(11q) with poor short-term outcomes (25% deaths/12 mo). Besides confirming the combinations of known risk-factors, the used patient similarity network added further refinement of subsets of HR-CLL patients who may profit from different targeted drugs.

CONCLUSIONS

This study showed for the first time in hemato-oncology the usefulness of the multivariate patient similarity networks for stratification of HR-CLL patients. This approach shows the potential for clinical implementation of precision medicine, which is especially important in view of an armamentarium of novel targeted drugs.

The importance of complex karyotype in prognostication and treatment of chronic lymphocytic leukemia (CLL): a comprehensive review of the literature

Cytogenetic examination and the detection of chromosomal aberrations in chronic lymphocytic leukemia (CLL) is an integral part of prognostic stratification and treatment decisions. Improvements in cytogenetic methods, notably the introduction of the cell stimulation method, have led to the detection of chromosomal aberrations in 80% of CLL cases. A comprehensive analysis of cytogenetic aberrations recently showed that complex karyotypes (CKs) defined as the detection of either three or more or five or more chromosomal changes in a karyotype have a poor prognostic impact. The current efforts at the international level are focused on the goal of including CK assessment among prognostic markers for CLL patients at diagnosis as well as after treatment. This review of the literature documents the clinical importance of CK findings in CLL and the necessity of including this factor in other poor prognostic indicators.

Cytogenetic complexity in chronic lymphocytic leukemia: definitions, associations, and clinical impact

Recent evidence suggests that complex karyotype (CK) defined by the presence of ≥3 chromosomal aberrations (structural and/or numerical) identified by using chromosome-banding analysis (CBA) may be relevant for treatment decision-making in chronic lymphocytic leukemia (CLL). However, many challenges toward the routine clinical application of CBA remain. In a retrospective study of 5290 patients with available CBA data, we explored both clinicobiological associations and the clinical impact of CK in CLL. We found that patients with ≥5 abnormalities, defined as high-CK, exhibit uniformly dismal clinical outcomes, independently of clinical stage, TP53 aberrations (deletion of chromosome 17p and/or TP53 mutations [TP53abs]), and the expression of somatically hypermutated (M-CLL) or unmutated immunoglobulin heavy variable genes. Thus, they contrasted with CK cases with 3 or 4 aberrations (low-CK and intermediate-CK, respectively) who followed aggressive disease courses only in the presence of TP53abs. At the other end of the spectrum, patients with CK and +12,+19 displayed an exceptionally indolent profile. Building upon CK, TP53abs, and immunoglobulin heavy variable gene somatic hypermutation status, we propose a novel hierarchical model in which patients with high-CK exhibit the worst prognosis, whereas those with mutated CLL lacking CK or TP53abs, as well as CK with +12,+19, show the longest overall survival. Thus, CK should not be axiomatically considered unfavorable in CLL, representing a heterogeneous group with variable clinical behavior. High-CK with ≥5 chromosomal aberrations emerges as prognostically adverse, independent of other biomarkers. Prospective clinical validation is warranted before ultimately incorporating high-CK in risk stratification of CLL.

Prognostic Factors in the Era of Targeted Therapies in CLL

PURPOSE OF REVIEW

Chronic lymphocytic leukemia is heterogeneous disease characterized by a variable clinical course that is greatly influenced by various patient and disease characteristics. Over the last two decades, advent of new diagnostic methodologies has led to the identification of several factors of prognostic and predictive relevance. Furthermore, recent advances in next-generation sequencing techniques has identified recurrent novel mutations in NOTCH1, SF3B1, BIRC3, and ATM genes whose role as prognostic and predictive markers is currently being investigated. These biologic markers carry new prognostic information and their incorporation into prognostic scoring systems will likely lead to refined multi-parameter risk models.

RECENT FINDINGS

While the prognostic impact of many of the most commonly used markers on clinical outcomes in patients treated with chemo-immunotherapy is well documented, it is important to review their predictive and prognostic role in the era of novel targeted therapies. This article will discuss the currently available information on the clinical relevance of prognostic markers in patients treated with novel targeted therapies.

Activation-induced deaminase and its splice variants associate with trisomy 12 in chronic lymphocytic leukemia

Activation-induced cytidine deaminase (AID) is a mutator enzyme essential for somatic hypermutation (SHM) and class switch recombination (CSR) during effective adaptive immune responses. Its aberrant expression and activity have been detected in lymphomas, leukemias, and solid tumors. In chronic lymphocytic leukemia (CLL) increased expression of alternatively spliced AID variants has been documented. We used real-time RT-PCR to quantify the expression of AID and its alternatively spliced transcripts (AIDΔE4a, AIDΔE4, AIDivs3, and AIDΔE3E4) in 149 CLL patients and correlated this expression to prognostic markers including recurrent chromosomal aberrations, the presence of complex karyotype, mutation status of the immunoglobulin heavy chain variable gene, and recurrent mutations. We report a previously unappreciated association between higher AID transcript levels and trisomy of chromosome 12. Functional analysis of AID splice variants revealed loss of their activity with respect to SHM, CSR, and induction of double-strand DNA breaks. In silico modeling provided insight into the molecular interactions and structural dynamics of wild-type AID and a shortened AID variant closely resembling AIDΔE4, confirming its loss-of-function phenotype.