CD38 expression and secondary 17p deletion are important prognostic factors in chronic lymphocytic leukaemia

The Value of Neutrophil Gelatinase-Associated Lipocalin Receptor as a Novel Partner of CD38 in Chronic Lymphocytic Leukemia: From an Adverse Prognostic Factor to a Potential Pharmacological Target?

Chronic lymphocytic leukemia (CLL) is characterized by the accumulation of neoplastic B lymphocytes that escape death, and correlates with the expression of negative prognostic markers such as the CD38 antigen. Although certain new drugs approved by the US Food and Drug Administration improve the clinical outcome of CLL patients, drug resistance and disease relapse still occur. Like CD38, neutrophil gelatinase-associated lipocalin receptor (NGAL-R) is frequently overexpressed in CLL cells. Here, we evaluated the concomitant surface expression of NGAL-R and CD38 in leukemic blood cells from 52 CLL patients (37 untreated, 8 in clinical remission, and 7 relapsed). We provide evidence of a positive correlation between NGAL-R and CD38 levels both in the interpatient cohorts (p < 0.0001) and in individual patients, indicating a constitutive association of NGAL-R and CD38 at the cell level. Patients with progressing CLL showed a time-dependent increase in NGAL-R/CD38 levels. In treated CLL patients who achieved clinical remission, NGAL-R/CD38 levels were decreased, and were significantly lower than in the untreated and relapsed groups (p < 0.02). As NGAL-R and CD38 participate in CLL cell survival, envisioning their simultaneous inhibition with bispecific NGAL-R/CD38 antibodies capable of inducing leukemic cell death might provide therapeutic benefit for CLL patients.

Immunoglobulin Gene Sequence as an Inherited and Acquired Risk Factor for Chronic Lymphocytic Leukemia

Simple Summary

Chronic lymphocytic leukemia (CLL) is the most prevalent among adult leukemias. Over the years, several research efforts discovered a lot of intricate details about the cause of the disease, its mechanism, and the prognostic factors that help to understand the progression and outcome of the disease. Mutations in the immunoglobulin gene sequences in B cells are the most important prognostic factor for CLL. The cells having no to very less mutations show aggressive disease, while those having more mutations are either fairly indolent or non-aggressive. In this review, we discussed the current gain of knowledge about these mutations and their effects in the overall disease pathology.

Abstract

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disease characterized by the accumulation of CD5⁺ CD19⁺ malignant B cells. Autonomous ligand-independent B-cell signaling is a key process involved in the development of CLL pathogenesis. Together with other cytogenetic alterations, mutations in the immunoglobulin heavy chain variable (IGHV) gene act as a prognostic marker for CLL, with mutated CLL (M-CLL) being far more indolent than unmutated CLL (U-CLL). Recent studies highlight the role of a specific light chain mutation, namely, IGLV3-21^R110G, in the development and prognosis of CLL. Such a mutation increases the propensity of homotypic BCR–BCR interaction, leading to cell autonomous signaling. In this article, we review the current findings on immunoglobulin gene sequence mutations as a potential risk factor for developing CLL.

Prognostic models for newly-diagnosed chronic lymphocytic leukaemia in adults: a systematic review and meta-analysis

BACKGROUND

Chronic lymphocytic leukaemia (CLL) is the most common cancer of the lymphatic system in Western countries. Several clinical and biological factors for CLL have been identified. However, it remains unclear which of the available prognostic models combining those factors can be used in clinical practice to predict long-term outcome in people newly-diagnosed with CLL.

OBJECTIVES

To identify, describe and appraise all prognostic models developed to predict overall survival (OS), progression-free survival (PFS) or treatment-free survival (TFS) in newly-diagnosed (previously untreated) adults with CLL, and meta-analyse their predictive performances.

SEARCH METHODS

We searched MEDLINE (from January 1950 to June 2019 via Ovid), Embase (from 1974 to June 2019) and registries of ongoing trials (to 5 March 2020) for development and validation studies of prognostic models for untreated adults with CLL. In addition, we screened the reference lists and citation indices of included studies.

SELECTION CRITERIA

We included all prognostic models developed for CLL which predict OS, PFS, or TFS, provided they combined prognostic factors known before treatment initiation, and any studies that tested the performance of these models in individuals other than the ones included in model development (i.e. 'external model validation studies'). We included studies of adults with confirmed B-cell CLL who had not received treatment prior to the start of the study. We did not restrict the search based on study design.

DATA COLLECTION AND ANALYSIS

We developed a data extraction form to collect information based on the Checklist for Critical Appraisal and Data Extraction for Systematic Reviews of Prediction Modelling Studies (CHARMS). Independent pairs of review authors screened references, extracted data and assessed risk of bias according to the Prediction model Risk Of Bias ASsessment Tool (PROBAST). For models that were externally validated at least three times, we aimed to perform a quantitative meta-analysis of their predictive performance, notably their calibration (proportion of people predicted to experience the outcome who do so) and discrimination (ability to differentiate between people with and without the event) using a random-effects model. When a model categorised individuals into risk categories, we pooled outcome frequencies per risk group (low, intermediate, high and very high). We did not apply GRADE as guidance is not yet available for reviews of prognostic models.

MAIN RESULTS

From 52 eligible studies, we identified 12 externally validated models: six were developed for OS, one for PFS and five for TFS. In general, reporting of the studies was poor, especially predictive performance measures for calibration and discrimination; but also basic information, such as eligibility criteria and the recruitment period of participants was often missing. We rated almost all studies at high or unclear risk of bias according to PROBAST. Overall, the applicability of the models and their validation studies was low or unclear; the most common reasons were inappropriate handling of missing data and serious reporting deficiencies concerning eligibility criteria, recruitment period, observation time and prediction performance measures. We report the results for three models predicting OS, which had available data from more than three external validation studies: CLL International Prognostic Index (CLL-IPI) This score includes five prognostic factors: age, clinical stage, IgHV mutational status, B2-microglobulin and TP53 status. Calibration: for the low-, intermediate- and high-risk groups, the pooled five-year survival per risk group from validation studies corresponded to the frequencies observed in the model development study. In the very high-risk group, predicted survival from CLL-IPI was lower than observed from external validation studies. Discrimination: the pooled c-statistic of seven external validation studies (3307 participants, 917 events) was 0.72 (95% confidence interval (CI) 0.67 to 0.77). The 95% prediction interval (PI) of this model for the c-statistic, which describes the expected interval for the model's discriminative ability in a new external validation study, ranged from 0.59 to 0.83. Barcelona-Brno score Aimed at simplifying the CLL-IPI, this score includes three prognostic factors: IgHV mutational status, del(17p) and del(11q). Calibration: for the low- and intermediate-risk group, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of four external validation studies (1755 participants, 416 events) was 0.64 (95% CI 0.60 to 0.67); 95% PI 0.59 to 0.68. MDACC 2007 index score The authors presented two versions of this model including six prognostic factors to predict OS: age, B2-microglobulin, absolute lymphocyte count, gender, clinical stage and number of nodal groups. Only one validation study was available for the more comprehensive version of the model, a formula with a nomogram, while seven studies (5127 participants, 994 events) validated the simplified version of the model, the index score. Calibration: for the low- and intermediate-risk groups, the pooled survival per risk group corresponded to the frequencies observed in the model development study, although the score seems to overestimate survival for the high-risk group. Discrimination: the pooled c-statistic of the seven external validation studies for the index score was 0.65 (95% CI 0.60 to 0.70); 95% PI 0.51 to 0.77.

AUTHORS' CONCLUSIONS

Despite the large number of published studies of prognostic models for OS, PFS or TFS for newly-diagnosed, untreated adults with CLL, only a minority of these (N = 12) have been externally validated for their respective primary outcome. Three models have undergone sufficient external validation to enable meta-analysis of the model's ability to predict survival outcomes. Lack of reporting prevented us from summarising calibration as recommended. Of the three models, the CLL-IPI shows the best discrimination, despite overestimation. However, performance of the models may change for individuals with CLL who receive improved treatment options, as the models included in this review were tested mostly on retrospective cohorts receiving a traditional treatment regimen. In conclusion, this review shows a clear need to improve the conducting and reporting of both prognostic model development and external validation studies. For prognostic models to be used as tools in clinical practice, the development of the models (and their subsequent validation studies) should adapt to include the latest therapy options to accurately predict performance. Adaptations should be timely.

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.

Evaluation of CD38 expression in Sudanese patients with chronic lymphocytic leukemia

Objective

The objective of this study was to evaluate the cluster of differentiation-38 (CD38) expression in Sudanese patients with chronic lymphocytic leukemia (CLL) and to determine its association with clinical and laboratory characteristics of the disease.

Results

We conducted a cross-sectional study on 99 patients diagnosed with CLL in Khartoum Oncology Hospital in Khartoum, Sudan. Immunophenotyping and CD38 expression levels were measured with four-color flowcytometry. The results of physical examination and blood analyses were used for assigning a modified Rai clinical staging system. The collected data were analyzed using the Statistical Package for the Social Science, version 22 (SPSS Inc., Chicago, IL, USA). According to our findings, the frequencies of 7%, 20%, and 30% cutoff levels of CD38 expressions were 68.7%, 41.4%, and 36.4% respectively. CD38 cutoff level of 7% showed a significant association with hemoglobin concentration (P = 0.04), whereas other cutoff levels showed insignificant results. All the three cutoff levels showed insignificant associations with the other clinical and laboratory variables. In conclusion, the CD38 expression at a cutoff level of 7% seems to be more valuable clinically than higher cutoff levels in Sudanese CLL patients.

CD38 knockout suppresses tumorigenesis in mice and clonogenic growth of human lung cancer cells

The ectodomain of the plasma membrane ectoenzyme CD38 functions as both an NAD glycohydrolase and an ADP-ribosyl cyclase by catalyzing, respectively, the conversion of NAD to nicotinamide and ADP-ribose or cyclic ADP-ribose. CD38 is attracting particular attention in cancer therapy. An anti-CD38 monoclonal antibody (daratumumab) was approved for treatment of patients with multiple myeloma. However, the role of CD38 in non-hematological malignancies has not been explored. Previously, we reported that ADP-ribose-acceptor hydrolase (ARH)-1 deficiency in mice was associated with tumor development. In the present study, we found that in wild-type and ARH1-deficient mice deletion of the CD38 gene reduced tumor formation. Significant reductions in tumor number were observed in lymphomas, adenocarcinomas and hemangio/histolytic sarcomas. Consistent with a role for CD38 in tumorigenesis, CRISPR/Cas9-based knockout of CD38 in A549 human adenocarcinoma cells inhibited anchorage-independent cell growth, cell invasion and xenograft growth in nude mice. CD38 mRNA and protein expression were evaluated in human lung cancer cell lines and in human lung cancer specimens. CD38 overexpression in tumor cells was identified in 11 of 27 patient samples. In addition, some human lung cancer cell lines had dramatically higher CD38 mRNA and protein expression than normal cells. Consistent with these observations, search of the Oncomine database showed that some human lung adenocarcinomas had higher CD38 mRNA levels compared to normal lung tissues. In total, our data are consistent with the conclusion that CD38 plays a role in murine and human lung tumorigenesis and that anti-CD38 treatment may have therapeutic potential in lung cancer.

Chronic Lymphocytic Leukemia in the Elderly, Which Investigations Are Necessary: A Map for the Practicing Oncologist

BACKGROUND

Chronic lymphocytic leukemia (CLL), the most prevalent leukemia in the Western world, is predominantly a disease of older individuals who also have other comorbidities as well as declining organ and bone marrow reserve. Although chemoimmunotherapy is the frontline therapy for fit CLL patients who can tolerate the therapy, many elderly patients cannot tolerate such intense therapy.

METHODS

The authors first reviewed the most recent findings concerning CLL cytogenetics, molecular biology, and prognostic models. They then surveyed recent and ongoing trials of novel CLL agents and strategies, with a focus on those most relevant to elderly patients.

RESULTS

Novel therapies, revised staging procedures, and careful assessment of individual patients' frailty and functional status will allow clinicians to provide optimal care management for older CLL patients.

CONCLUSION

Therapy for the elderly CLL population must be tailored to each patient's fitness level and comorbid conditions, with special consideration for the potential quality-of-life impacts of various treatment recommendations.

CD49d shows superior performance characteristics for flow cytometric prognostic testing in chronic lymphocytic leukemia/small lymphocytic lymphoma

BACKGROUND

CD49d is emerging as a powerful adverse prognostic marker in chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL). However, flow cytometric testing for CD49d has not yet been widely adopted in the United States, in part due to the lack of establishment of its performance characteristics in the clinical setting, especially in comparison with the more common CLL/SLL prognostic markers CD38 and ZAP-70.

METHODS

CD49d expression levels in 124 CLL/SLL cases were assessed among peripheral blood (PB), bone marrow (BM), and lymph node (LN) specimens and correlated with available CD38 and ZAP-70 expression and cytogenetic findings. For 10 PB/BM specimens, the stability of CD49d, CD38, and ZAP-70 expression was assessed at <24 hours, 48 hours, 72 hours, and 96 hours.

RESULTS

39% (28 of 71) PB, 56% (18 of 32) BM, and 71% (15 of 21) LN involved by CLL/SLL were CD49d+, using a ≥30% threshold. The mean for the CD49d+ cases was 2.8 standard deviations (SD) above the cutoff for positivity, compared with 1.7 SD for CD38 and 1.1 SD for ZAP-70. CD49d demonstrated the lowest mean SD (0.91) and coefficient of variation (CV) (8.0%) compared with CD38 (SD = 2.1, CV = 10.4%) and ZAP-70 (SD = 9.8, CV = 40.5%) in stability studies over a 96-hours time period. CD49d+ CLL/SLL correlated with trisomy 12 (P = 0.025) and lack of isolated deletion (13q) (P = 0.005). CD38+ CLL/SLL correlated with deletion (11q) (P = 0.025). ZAP-70 did not correlate with any underlying cytogenetic abnormality.

CONCLUSIONS

CD49d is a robust adverse prognostic marker in CLL/SLL with superior performance characteristics. © 2016 International Clinical Cytometry Society.

Watch and Wait in Lebanese Chronic Lymphocytic Leukemia Patients: How Relevant is it?

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most frequent form of leukemia in Europe and North America, and it mainly affects older individuals. Many approaches are implemented in the management of CLL from a watch and wait (WandW) strategy to chemotherapeutic regimens. We here reviewed our clinical practice for the relevance of the W and W strategy in Lebanese CLL patients.

MATERIALS AND METHODS

A total of 95 patients with CLL diagnosed in four institutions in Lebanon, between 1992 and 2013, were selected and their files were reviewed. Characteristics of these patients were noted including age, sex, RAI and Binet scores, CBC values, presence of hepatomegaly or splenomegaly, performance of bone marrow biopsy or peripheral blood flux cytometry for diagnosis, adoption of W and W strategy, different chemotherapeutic regimens and the indications for treatment.

RESULTS

Some 38 patients (40%) diagnosed with CLL were women and 57 (60%) were men with a mean age of 65.1 years [36-89]. Of the total, 50.5%, 17.2%, 14%, 7.5% and 10.8% had an RAI score at diagnosis of 0, 1, 2, 3 and 4, respectively, while 65.6%, 17.2% and 17.2% had Binet scores of I, II and III. The mean lymphocyte count at diagnosis was 39885/mm3 [1596-290000], the mean hemoglobin level was 12.7 g/dl [6.2-17] and the mean platelet count was 191255/mm3 [14000-458000]. While 26.3% of patients with CLL had splenomegaly, only 7.4% had hepatomegaly. Some 33.7% had undergone a bone marrow biopsy, 66.3% flow cytometry of circulating blood and 5.3% a lymph node biopsy. Overall, the W and W was adopted in 62.4% (58) of patients with a mean duration of 37.7 months [3-216]. The W and W was used in 82.6%, 73.3%, 46.2%, 14.3% and 0% of patients having RAI scores of 0, 1, 2, 3 and 4, respectively, and, it was used in 80%, 46.7% and 6.25% with Binet scores of I, II and III. The most frequent indication for treatment was anemia and thrombocytopenia, accounting for 32.7% of cases. The most frequently used chemotherapeutical regimens were chlorambucil until the end of the last century and flufarabine-cyclophosphamide-rituximab during the last decade.

CONCLUSIONS

This retrospective review of CLL clinical practice showed an important implementation of the W and W strategy with a long duration, especially in early stage cases with low RAI or Binet scores.

De novo deletion 17p13.1 as a predictor for disease progression in chronic lymphocytic leukemia

To determine the prognostic impact of de novo deletion 17p13.1 (17p-) in previously untreated chronic lymphocytic leukemia (CLL) patients, we prospectively studied the outcome of 71 treatment-naïve CLL patients. About 18.3 % of them had 17p- detected by interphase fluorescent in situ hybridization (FISH) at diagnosis. There was statistically significant difference between 17p- negative and positive patients as regards 2-year overall survival [OS] (89.7 vs. 53.8 %, respectively; P = 0.001). On the other hand, 2-year progression-free survival [PFS] was also significantly higher in 17p- negative group than in 17p- positive one (82.8 vs. 23.1 %, respectively; P < 0.001). On univariate analysis for OS, 17p- positivity was significantly associated with shorter OS (P = 0.003). However, when we performed multivariate analysis, 17p- lost its significant impact. On the other hand, 17p- positivity was a significant risk factor for PFS in both univariate and multivariate analyses [independent risk factor] (P < 0.001 and P = 0.02, respectively). So, 17p- is a predictor for disease progression, but not for survival in CLL patients.

Role of allogeneic transplantation in patients with chronic lymphocytic leukemia in the era of novel therapies: a review

Chronic lymphocytic leukemia (CLL) is the most common form of adult leukemia and is characterized by a highly variable clinical course. In the past decade, several prognostic risk factors have been identified facilitating the classification of CLL into various risk groups. Patients with poor risk disease, such as poor cytogenetics or relapsing after purine-based analogues, had limited therapeutic options, with allogeneic hematopoietic cell transplantation (allo-SCT) the only known therapy with curative potential. More recently, the introduction of novel agents inhibiting the B-cell receptor pathway, and the early success with chimeric antigen receptor T cells offers an effective and relatively safe option for this poor prognostic group which holds promise in the future. Alternatively, the use of reduced intensity conditioning regimens in the allo-SCT setting has led to a significant decrease in nonrelapse mortality to 16-23%, making it an attractive therapeutic option. No recent guidelines have been developed since these novel therapies became available regarding the optimal time to allo-SCT in this patient population. The advent of these novel and highly active therapeutic agents, therefore, warrants a reappraisal of the role and timing of allo-SCT in patients with CLL. In this article, we summarize the literature regarding the novel therapeutic agents available today as well as focus on the efficacy and safety of allo-SCT.

Ectonucleoside triphosphate diphosphohydrolase-1 (E-NTPDase1/CD39) as a new prognostic marker in chronic lymphocytic leukemia

Numerous prognostic markers were introduced to screen for patients with B-cell chronic lymphocytic leukemia (B-CLL) likely to have a progressive course, bearing the potential to facilitate risk-adapted treatment strategies. Extracellular adenosine triphosphate (ATP) functions as a "natural adjuvant" that boosts immune response in the tumor microenvironment. Ectonucleoside triphosphate diphosphohydrolase-1 (CD39/ENTPD1) is the ectonucleotidase that catalyzes the hydrolysis of ATP. The present study was conducted to analyze CD39 expression in T cells and B-CLL cells to evaluate its impact on the clinical course of patients with B-CLL and correlate its levels with well-established risk factors. T-cell CD39 expression was significantly increased in patients' peripheral blood compared to healthy controls. The higher levels were associated with advanced stages of disease and negatively interacted with time to first treatment. Overall, our data indicate that T-cell CD39 expression may identify subsets of patients with B-CLL with an unfavorable clinical outcome. Moreover, it can be incorporated into prognostic schema to improve the prediction of CLL disease progression.

Clonal evolution in chronic lymphocytic leukemia: analysis of correlations with IGHV mutational status, NOTCH1 mutations and clinical significance

Chronic lymphocytic leukemia (CLL) is a lymphoproliferative disorder characterized with highly variable clinical course. The most common chromosomal abnormalities in CLL, using conventional and molecular cytogenetics, are trisomy 12, del(13)(q14), del(11)(q22-23), del(17)(p13), and del(6)(q21). Whereas the prognostic marker such as IGHV mutational status remains stable during course of the diseases, chromosomal aberrations may be acquired over time. The aim of this study was to determine the incidence, and biological significance of clonal evolution (CE) using conventional and molecular cytogenetics and its relationship with prognostic markers such as CD38, ZAP70, and the mutational status of IGHV and NOTCH1. One hundred and forty-three untreated CLL patients were included in the study. The median time interval between analyses was 32 months (range 6-156 months). Forty-seven patients (33%) had CE as evidenced by detection of new cytogenetic abnormalities during follow-up. CE was not correlated with high expression of ZAP70, unmutated IGHV genes or NOTCH1 mutations. Multivariate analysis revealed that CE and IGHV mutation status had a significant impact on TFS. The combination of conventional and molecular cytogenetics increased the detection of CE, this phenomenon probably being a reflection of genomic instability and conferring a more aggressive clinical course.

FISH Analysis for del6q21 and del17p13 in B-cell Chronic Lymphocytic Leukemia in Iranians

BACKGROUND

B-cell chronic lymphocytic leukemia (B-CLL) is the most common leukemia in the Western world. Major progress has been made in assessing typical chromosomal abnormalities and recognition of the correlation of these chromosomal abnormalities with laboratory features and clinical course of the disease. The most frequent genomic changes are deletions at 13q14, 11q22-23 and 17p13 and trisomy of chromosome 12.

OBJECTIVES

The aim of this study was to investigate the frequency of chromosomal aberrations in B-CLL patients' peripheral blood and/or bone marrow using a molecular cytogenetic method, interphase fluorescence in situ hybridization (I-FISH) and to evaluate the correlation between these genomic changes and clinical findings.

PATIENTS AND METHODS

I-FISH analyses were performed on bone marrow and blood samples of 66 B-CLL patients.

RESULTS

Deletion of 17p13 was found in 11 (16.6%) and deletion 6q21 was present in 5 (7.5%). Statistical analyses were performed to investigate the correlation of these molecular-cytogenetic findings with family history, Rai staging and CD38 marker. No clear differences in distribution was noted for del17p13 and del6q21 among patients with and without family history, and no direct correlation was noted between these genomic changes and CD38 marker, but the correlation of del17p13 and Rai stage was significant. There was a high frequency of Rai stage II within del17p13 patients.

CONCLUSIONS

It was demonstrated that the presence of del6q21 in B-CLL patients indicates poor prognosis and on the contrary, presence of del17p13 points at the good prognostic value of the disease.

Surface profiles for subclassification of chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) has a variable clinical course. Some patients have stable disease while others progress and require treatment. Levels of several cluster of differentiation (CD) antigens are known to correlate with prognosis and may be used to stratify patients according to risk. In this review, we summarize current information on surface CD antigens found on CLL, their pathological significance and their detection using CD antibody microarrays. The use of extensive immunophenotypic patterns or surface profiles as disease signatures for CLL subclassification, prognosis and patient management is discussed with a focus on triaging patients with CLL with progressive disease.

Predicting survival in chronic lymphocytic leukemia

There is increasing interest in the use of prognostic markers that may predict survival and guide management in patients diagnosed with the early stages of chronic lymphocytic leukemia (CLL). Currently, the most important traditional prognostic factors include clinical staging, lymphocyte doubling time and β2-microglobulin/thymidine kinase; and the most important novel markers include karyotypic aberrations (typically assessed by FISH probes or CpG oligonucleotide karyotyping) and IgVH mutation status. Although each of these factors have individually shown significant correlations with survival, there is increasing appreciation that the most complete information may be obtained by using a combination of several factors in prognostic normograms or models. In this article, we review the current state-of-the-art with regards to CLL prognostic factors and discuss how they can be applied in the clinic.

Clinical and Laboratory Prognostic Indicators in Chronic Lymphocytic Leukemia

Background

The clinical course of patients with chronic lymphocytic leukemia (CLL) is heterogeneous, with some patients experiencing rapid disease progression and others living for decades without requiring treatment. The Rai and Binet clinical staging systems are used to define disease extent and predict survival. The pathology laboratory also provides important prognostic information.

Methods

A review of the literature was performed on the subject of staging in CLL from clinical and pathologic standpoints. This article also reviews currently available diagnostic approaches related to disease prognosis and to timing of treatment and follow-up in patients with CLL.

Results

Novel biological and cytogenetic features such as immunoglobulin heavy-chain variable gene segment [IgVH], genomic aberrations including del(17p13), del(11q23), del(13q14), and trisomy 12, serum markers (thymidine kinase and beta-2 microglobulin), and cellular markers (CD38 and ZAP70) have become increasingly important in predicting prognosis at the time of diagnosis.

Conclusions

Current prognostic factors directly or indirectly influence the management of patients with CLL and help to predict treatment-free and overall survival.

Prospective study of clinical and biological prognostic factors at diagnosis in patients with early stage B-cell chronic lymphocytic leukemia

Retrospective series have reported many clinical and biological significant prognostic factors in chronic lymphocytic leukemia (CLL). We describe a prospective cohort of 135 patients with CLL homogeneously studied at diagnosis for prognostic factors. Biological variables analyzed were CD38 and ZAP-70 expression, fluorescence in situ hybridization (FISH) for 13q-, +12, 11q-, and 17p-, and conventional cytogenetics. Univariate and multivariate analysis for progression-free survival (PFS) were performed in patients with early stage (Rai 0-1) CLL. CD38 was positive in 42 (31.6%) patients and ZAP-70 in 47 (35.9%). The most frequent FISH finding was isolated 13q- in 50 (38.5%) patients, and 17p- -was found in 11 (8.4%). Among 135 patients, 114 (84.4%) were Rai 0-1 at diagnosis and 39 (28.9%) presented adenopathies. With a median follow-up of 39 months, the presence of lymphadenopathy in patients with Rai 0-1 stage CLL was the only significant variable for predicting PFS in multivariate analysis (odds ratio [OR] 7, 95% confidence interval [CI] 2.2-22, p = 0.001). When only biological factors were analyzed, CD38 expression (OR 3.2, 95% CI 1.1-9.3, p = 0.03) and 17p- (OR 3.5, 95% CI 0.95-13.1, p = 0.05) correlated with worse PFS. A longer follow-up is necessary to analyze the prognostic value of these variables regarding overall survival.

Enhanced detection of chromosomal abnormalities in chronic lymphocytic leukemia by conventional cytogenetics using CpG oligonucleotide in combination with pokeweed mitogen and phorbol myristate acetate

Reproducible cytogenetic analysis in CLL has been limited by the inability to obtain reliable metaphase cells for analysis. CpG oligonucleotide and cytokine stimulation have been shown to improve metaphase analysis of CLL cytogenetic abnormalities, but is limited by variability in the cytokine receptor levels, stability and biological activity of the cytokine in culture conditions and high costs associated with these reagents. We report here use of a novel, stable CpG, GNKG168 along with pokeweed mitogen (PWM) and phorbol 12-myristate 13-acetate (PMA) for conventional cytogenetic assessment in CLL. We demonstrate that the combined use of GNKG168+PWM/PMA increased the sensitivity of detection of chromosomal abnormalities compared to PWM/PMA (n=207, odds ratio=2.2, p=0.0002) and GNKG168 (n=219, odds ratio=1.5, p=0.0452). Further, a significant increase in sensitivity to detect complexity ≥3 with GNKG168+PWM/PMA compared to GNKG168 alone (odds ratio 8.0, p=0.0022) or PWM/PMA alone (odds ratio 9.6, p=0.0007) was observed. The trend toward detection of higher complexity was significantly greater with GNKG168+PWM/PMA compared to GNKG168 alone (p=0.0412). The increased sensitivity was mainly attributed to the addition of PWM/PMA with GNKG168 because GNKG168 alone showed no difference in sensitivity for detection of complex abnormalities (p=0.17). Comparison of fluorescence in situ hybridization (FISH) results with karyotypic results showed a high degree of consistency, although some complex karyotypes were present in cases with no adverse FISH abnormality. These studies provide evidence for potential use of GNKG168 in combination with PWM and PMA in karyotypic analysis of CLL patient samples to better identify chromosomal abnormalities for risk stratification.

Prognostic factors in chronic lymphocytic leukemia-what do we need to know?

Of all leukemias, chronic lymphocytic leukemia (CLL) shows the highest variability in its clinical presentation and course. CLL can present as an aggressive and life threatening leukemia or as an indolent form that will not require treatment over decades. The currently available clinical staging systems for CLL are simple and inexpensive but lack accuracy to predict disease progression and survival on an individual basis. The increased understanding of the key events of molecular pathogenesis has provided a plethora of novel molecular and biological factors that correlate with the outcome of CLL. This Review provides a concise discussion of the most important discoveries and gives guidance on how to implement novel prognostic tools in the clinical management of CLL by applying the criteria of evidence, relevance, and simplicity to the selection of prognostic markers.

11q22.3 deletion in B-chronic lymphocytic leukemia is specifically associated with bulky lymphadenopathy and ZAP-70 expression but not reduced expression of adhesion/cell surface receptor molecules

The presence of chromosome abnormalities promotes tumor progression in B-chronic lymphocytic leukemia (CLL). However, the molecular pathways that are relevant to tumor progression remain unclear. In this study, we screened for common chromosome abnormalities [13q14 del, 11q22.3 (ATM) del, 17p13 (p53) del and trisomy 12] by fluorescent in situ hybridization in 40 B-CLL patients. Each of the four chromosome abnormality groups was compared to several clinical factors related to lymphocyte behaviour in CLL. The 11q22.3 (ATM) deletion group was significantly associated with the presence of bulky abdominal/mediastinal lymphadenopathy (P = 0.014). We hypothesized that this phenotype would be associated with an altered transcription pattern of genes. Class comparison analysis by significance analysis of microarrays on a subset of CLL samples (n = 14) indicated that a number of cell surface receptor and adhesion related genes were under-expressed in the 11q22.3 deletion group (CD44, CD11a, PTPRC, CD79a, chemokine ligand 17 and chemokine receptor type 6). The presence of additional prognostic factors, such as CD38 and immunoglobulin heavy chain variable region mutational status, may also influence the transcriptional pathways between the two groups. Therefore, we employed a novel analysis technique for the correlation of log(2) gene expression ratios with the percentage of each tumor that carried the 11q22.3 deletion. Using Spearman's correlation, ZAP-70, chemokine ligand 17, BSAP (PAX5), CD7, LAG3 and PTPR6 were significantly correlated with the percentage of cells with the 11q22.3 deletion. However, the down-regulation of cell surface receptors and adhesion molecules observed by class comparison could not be confirmed to be specific for the 11q22.3 deletion by this method.

CD38 expression level and pattern of expression remains a reliable and robust marker of progressive disease in chronic lymphocytic leukemia

Chronic lymphocytic leukemia (CLL) follows a variable clinical course which is difficult to predict at diagnosis. We assessed somatic mutation (SHM) status, CD38 and ZAP-70 expression in 87 patients (49 male, 38 female) with stage A CLL and known cytogenetic profile to compare their role in predicting disease progression, which was assessed by the treatment free interval (TFI) from diagnosis. Sixty (69%) patients were SHM+, 24 (28%) were CD38+ and ten (12%) were ZAP-70+. The median TFI for: (i) SHM + versus SHM- patients was 124 versus 26 months; hazard ratio (HR) = 3.6 [95% confidence interval (CI) = 1.8 - 7.3; P = 0.001]: (ii) CD38- versus CD38+ patients was 120 versus 34 months; HR = 2.4 (95% CI = 1.4 - 5.3; P = 0.02); and (iii) ZAP70- versus ZAP70+ was 120 versus 16 months; HR = 3.4 (95% CI = 1.4 - 8.7; P = 0.01). SHM status and CD38 retained prognostic significance on multivariate analysis whereas ZAP-70 did not. We conclude that ZAP-70 analysis does not provide additional prognostic information in this group of patients.

T-cell CD38 expression in B-chronic lymphocytic leukaemia

B-cell chronic lymphocytic leukaemia (B-CLL) is a heterogeneous disease with some patients having an indolent course never needs treatment, while others having rapidly progressive one requires intensive treatment. In recent decades, numerous prognostic markers, such as immunoglobulin variable region heavy-chain (IgVH) mutational status, ZAP-70 and the expression of CD38 on leukaemic cells were introduced to screen for patients likely to have progressive course of B-CLL bearing the potential to facilitate risk-adapted treatment strategies. In B-CLL, T cell function is shown to be dysregulated. CD38 has been demonstrated to be an important transmembrane signalling molecule of T cell with a direct effect on its function. The present study was conducted to analyse CD38 expression on T cells by flow cytometry to evaluate its impact on the clinical course of 88 unselected B-CLL patients and correlate it with other risk factors. CD38 expression level on T cells was shown to predict the clinical course of B-CLL in male patients but not in female patients. Male patients showed CD38 expression on T cells in a stage-dependent manner, in contrast to female patients who showed higher expression irrespective to clinical staging. CD38 expression on T cells negatively interacted with treatment-free survival in male patients. Multivariate analysis revealed that CD38 expression level on T cells is an independent prognostic factor in B-CLL male patients. Simultaneous evaluation of CD38 expression on both B-CLL cells and T cells allowed predicting male patient groups with the most favourable prognosis as well as those with the worst.

Evolution and function of the ADP ribosyl cyclase/CD38 gene family in physiology and pathology

The membrane proteins CD38 and CD157 belong to an evolutionarily conserved family of enzymes that play crucial roles in human physiology. Expressed in distinct patterns in most tissues, CD38 (and CD157) cleaves NAD(+) and NADP(+), generating cyclic ADP ribose (cADPR), NAADP, and ADPR. These reaction products are essential for the regulation of intracellular Ca(2+), the most ancient and universal cell signaling system. The entire family of enzymes controls complex processes, including egg fertilization, cell activation and proliferation, muscle contraction, hormone secretion, and immune responses. Over the course of evolution, the molecules have developed the ability to interact laterally and frontally with other surface proteins and have acquired receptor-like features. As detailed in this review, the loss of CD38 function is associated with impaired immune responses, metabolic disturbances, and behavioral modifications in mice. CD38 is a powerful disease marker for human leukemias and myelomas, is directly involved in the pathogenesis and outcome of human immunodeficiency virus infection and chronic lymphocytic leukemia, and controls insulin release and the development of diabetes. Here, the data concerning diseases are examined in view of potential clinical applications in diagnosis, prognosis, and therapy. The concluding remarks try to frame all of the currently available information within a unified working model that takes into account both the enzymatic and receptorial functions of the molecules.

CD38 as a prognostic factor in Chinese patients with chronic lymphocytic leukaemia

B-cell chronic lymphocytic leukemia (CLL) is the most common type of adult leukemia in the Western countries, however, infrequent in the Eastern. It shows a remarkable heterogeneity, with some patients having an almost normal lifespan, others surviving only several years after diagnosis despite intensive therapy. To explore the prognostic significance of CD38 expression in Chinese patients with CLL, multi-parameter flow cytometry was used to detect the expression of CD38 on CD5(+)CD19(+) cells of 147 patients. CD38 expression and its association with some other prognostic factors such as Binet stage, lymphocyte count in peripheral blood, serum lactate dehydrogenase (LDH), beta2-microglobulin (beta2-MG), ZAP-70 expression and cytogenetic abnormalities were analyzed. The Kaplan-Meier method was used to construct survival curves, and results were compared using the log-rank test. Univariate and multivariate Cox regression analyses were used to assess associations between survival time and potential risk factors. Out of the 147 CLL patients, positive expression of CD38 was found in 45 (30.6%) cases. CD38-positivity identified a subgroup of CLL patients with aggressive disease of Binet stage at the time of the test (P=0.036). Furthermore, the presence of higher serum LDH and beta2-MG levels at diagnosis was strongly correlated with CD38-positive (P=0.016 and 0.025, respectively). Prognostically unfavorable cytogenetic abnormalities, including 17p13 and 11q22 deletions, were significantly more frequent in CD38-positive patients than in CD38-negative ones (P=0.047 and 0.001, respectively). There was no significant difference between CD38-positive and CD38-negative groups in molecular cytogenetic aberrations of del(6q23), del(13q14), 14q32 translocation, or trisomy 12. In addition, in CD38-positive patients, the percentage of leukemic cells expressing ZAP-70 protein was not significantly higher than in CD38-negative ones (P=0.120). CD38 expression was associated with poor outcome. Patients with positive expression of CD38 had significantly shorter overall survival (mean, 81 months) than patients without CD38 expression (mean, 179 months) (P=0.015). Univariate analysis showed that serum levels of LDH and beta2-MG, del(17p13) and CD38 expression were the significant factors in determining overall survival (OS). Del(17p13) and CD38 expression were the variables strongly associated with OS by multivariate Cox regression analysis. It was showed that the patients with high level of CD38 expression had poorer outcome; CD38 was a good predictor of OS in Chinese patients with CLL.

CD38 gene polymorphism and chronic lymphocytic leukemia: a role in transformation to Richter syndrome?

CD38 rules proliferation signals in chronic lymphocytic leukemia (CLL) cells, suggesting that the molecule is not merely a prognostic marker but also a key element in the pathogenetic network underlying the disease. CD38 has a genetic polymorphism, characterized by a C>G variation in the regulatory region of intron 1. The working hypothesis is that the presence of different alleles in CLL patients marks (or accounts for) some of the clinical heterogeneity. CD38 allele distribution in 248 Italian patients overlapped with that of the controls (n = 232), suggesting that susceptibility to CLL is not influenced by CD38 genotype. Stratification of patients according to markers of unfavorable prognosis constantly resulted in a significantly higher frequency of the rare G allele. Furthermore, analysis of clinical parameters showed that G allele is independently associated with nodal/splenic involvement. The highest G allele frequency was observed in the 16 patients of the cohort that developed Richter syndrome (RS). Five-year cumulative incidence of transformation was significantly higher in G allele carriers than in CC homozygotes. Multivariate analysis on a total of 30 RS patients confirmed that the probability of transformation is strongly associated with G allele, likely representing an independent risk factor for RS development.

ZAP70 expression assessed by immunohistochemistry on peripheral blood: a simple prognostic assay for patients with chronic lymphocytic leukemia

The somatic hypermutational (SHM) status of the immunoglobulin heavy-chain variable (IgVH) gene is a powerful prognostic factor in patients with chronic lymphocytic leukemia (CLL). However, IgVH SHM analysis is not well-suited to routine use in the clinical diagnostic laboratory. ZAP70 expression is a potential surrogate for the absence of SHM. Given the current problems with the standardization of ZAP70 assessment by flow cytometry, we sought an alternative approach, using immunohistochemistry (IHC). The utility of IHC is largely restricted to tissues, precluding its routine application to most patients with CLL who are typically diagnosed based upon peripheral blood (PB) findings. Accordingly, we developed an IHC assay that can be performed on PB. Enriched PB mononuclear cells from 29 patients with CLL were analyzed for ZAP70 expression by IHC on paraffin-embedded cell blocks, using standard techniques. IgVH SHM analysis was performed on all cases, and clinical features recorded. Seventeen specimens (59%) were negative for ZAP70 expression and 12 (41%) were positive for ZAP70 expression. SHM was evident in 20 specimens (69%), and absent in 9 (31%). Seventy-six percent of the specimens (22/29) displayed "concordant" ZAP70 and SHM results, in that 15 (52%) were SHM-positive/ZAP70 negative, whereas 7 (24%) were SHM-negative/ZAP70 positive. ZAP70 expression in this small cohort correlated with poor clinical outcome. Importantly, IHC analysis of ZAP70 in PB is a simple, reliable, robust assay that may have a valuable role in the routine clinical laboratory assessment of patients with CLL.

Igbeta(CD79b) mRNA expression in chronic lymphocytic leukaemia cells correlates with immunoglobulin heavy chain gene mutational status but does not serve as an independent predictor of clinical severity

The etiology of chronic lymphocytic leukemia (CLL) is poorly understood and its course is highly variable. Somatic hypermutation (SHM) of the immunoglobulin heavy chain (IgV(H)) gene and ZAP70 protein expression have been reported as prognostic indicators. However, these assays are not widely available and their concordance is imperfect. Thus a need exists to identify additional molecular determinants of CLL. The Igbeta (CD79b) subunit of the B cell antigen receptor is essential for B lymphocyte function. Defects in Igbeta expression are implicated in CLL pathogenesis. We have analyzed Igbeta mRNA expression in CLL cells in 40 consecutive patient samples. About 75% of the samples showed the expected decrease of Igbeta surface staining. Igbeta mRNA levels covered a wider range, did not correlate with Igbeta surface staining, but clearly distinguished the normal and CLL lymphocyte populations. Remarkably, Igbeta mRNA levels correlated strongly with SHM; Igbeta mRNA levels in CLL cells were significantly higher in patients with an unmutated IgV(H) gene when compared with those in whom IgV(H) was hypermutated (P = 0.008). In contrast, no correlation was observed between Igbeta mRNA levels and ZAP70 expression. Multiple parameters abstracted from chart reviews were used to estimate severity of CLL in each case. While severity correlated strongly with ZAP70 staining, and to a lesser extent with SHM status, there was no correlation with Igbeta mRNA levels. These data establish a strong linkage between Igbeta mRNA expression and SHM in CLL and highlight the complex relationships between biochemical parameters and clinical status in this disease.

Comparison of a quantitative PCR method with FISH for the assessment of the four aneuploidies commonly evaluated in CLL patients

Four chromosomal defects associated with outcome are commonly evaluated by fluorescent in situ hybridization (FISH) in chronic lymphocytic leukemia (CLL), namely deletions of the 13q13-q14, 11q22 and 17p13 regions and trisomy 12. In this study, we compared a quantitative PCR method--quantitative multiplex PCR of short fluorescent fragment (QMPSF)--with FISH for the detection of these acquired aneuploidies in a series of 110 patients with Binet stage A CLL. Genes located in the deleted or gained regions were selected as target genes and amplified using a method based on the simultaneous amplification of short fluorescent genomic fragments under quantitative conditions. A chromosomal imbalance involving one or several of the four loci was detected by either method in 72 patients (65%). A chromosome 13 deletion was present in 61 patients (54%), a 11q22 deletion in nine (8%), a trisomy 12 in nine and a 17p deletion in one. FISH and QMPSF results were identical for 103 out of 110 patients and discrepancies could be explained in most cases. This study demonstrates that a quantitative multiplex PCR represents a cost-effective method that could replace FISH in CLL patients. However, although QMPSF is perfectly adapted to the detection of primary defects, care should be taken when searching for clonal evolutions present in a small proportion of tumor cells.

Cytogenetic abnormalities additional to t(11;14) correlate with clinical features in leukaemic presentation of mantle cell lymphoma, and may influence prognosis: a study of 60 cases by FISH

Mantle cell lymphoma (MCL), characterised by t(11;14)(q13;q32), has a poor prognosis. Many cases have additional cytogenetic abnormalities, and often have a complex karyotype. Fluorescence in situ hybridisation (FISH) was used to study 60 cases with leukaemic presentation of MCL, to determine the frequency, clinical correlations and prognostic impact of a panel of molecular cytogenetic abnormalities: 17p13 (TP53 locus), 13q14, 12 p11.1-q11 (centromere), 6q21 and 11q23. CD38 expression, of prognostic value in chronic lymphocytic leukaemia (CLL), was also studied, and correlations with clinical and cytogenetic abnormalities sought. Eighty per cent of cases had at least one abnormality in addition to t(11;14). Deletions at 17p13 (TP53) and 13q14 were most frequent and involved the majority of the leukaemic clone. Cases with TP53 deletion were more likely to have splenomegaly and marked leucocytosis (>30 x 10(9)/l), and less likely to have lymphadenopathy than those without deletion. Deletions at 11q23 and 6q21 were associated with extranodal disease. 13q14 and 11q23 deletions showed a trend towards worse prognosis by univariate analysis. In multivariate analysis, deletions at 13q14 and 6q21 were independent predictors of poor outcome. Deletion at 17p13 did not show prognostic impact in this series. CD38, positive in two-thirds of cases, was associated with male gender and nodal disease but not with any cytogenetic abnormality, or with survival.

Prospective evaluation of clonal evolution during long-term follow-up of patients with untreated early-stage chronic lymphocytic leukemia

PURPOSE

Retrospective studies suggest cytogenetic abnormalities detected by interphase fluorescent in situ hybridization (FISH) can identify patients with chronic lymphocytic leukemia (CLL) who will experience a more aggressive disease course. Other studies suggest that patients may acquire chromosome abnormalities during the course of their disease. There are minimal prospective data on the clinical utility of the widely used hierarchical FISH prognostic categories in patients with newly diagnosed early-stage CLL or the frequency of clonal evolution as determined by interphase FISH.

PATIENTS AND METHODS

Between 1994 and 2002, we enrolled 159 patients with previously untreated CLL (83% Rai stage 0/I) on a prospective trial evaluating clonal evolution by FISH. Patients provided baseline and follow-up specimens for FISH testing during 2 to 12 years.

RESULTS

Chromosomal abnormalities detected by FISH at study entry predicted overall survival. Eighteen patients experienced clonal evolution during follow-up. The rate of clonal evolution increased with duration of follow-up with only one occurrence in the first 2 years (n = 71; 1.4%) but 17 occurrences (n = 63; 27%) among patients tested after 5+ years. Clonal evolution occurred among 10% of ZAP-70-negative and 42% of ZAP-70-positive patients at 5+ years (P = .008).

CONCLUSION

This clinical trial confirms prospectively that cytogenetic abnormalities detected by FISH can predict overall survival for CLL patients at the time of diagnosis, but also suggests that many patients acquire new abnormalities during the course of their disease. Patients with higher ZAP-70 expression may be more likely to experience such clonal evolution. These findings have important implications for both clinical management and trials of early treatment for patients with high-risk, early-stage CLL.

The effect of immunoglobulin VH gene mutation status and other prognostic factors on the incidence of major infections in patients with chronic lymphocytic leukemia

BACKGROUND

Infections are a major factor in the clinical course of chronic lymphocytic leukemia (CLL) and account for 30% to 50% of all deaths. The pathogenesis of infections in CLL is related to hypo-gamma-globulinemia, T-cell immune dysfunction, and the immunosuppressive effect of treatment.

METHODS

The authors retrospectively assessed the correlations between new prognostic markers and types of infections encountered, the time taken to develop these infections, and infection-related mortality in 280 unselected patients with CLL.

RESULTS

One hundred patients (36%) had at least 1 major infection (median, 2 major infections; range, 1-8 major infections) over a median follow-up of 67 months. Infections were the most common cause of death, accounting for 51% of all fatalities. Older age (P = .007), clinical Stage B or C disease (P < .001), unmutated immunoglobulin (Ig)VH gene status (P < .001), genetic abnormalities (P < .001), positive CD38 status (P < .001), and type of initial therapy were associated with a significantly shorter time to first infection. Equally, patient age (P < .001), disease stage (P < .001), CD38 expression (P < .001), IgVH mutation status (P < .001), and genetic abnormalities (P = .003) had a significant impact on infection-related mortality.

CONCLUSIONS

Clinical stage at diagnosis, IgVH mutation status, and initial therapy were possible predictors of severe infections in patients with CLL. The current results may help to identify which patients with CLL are at particularly high risk of developing serious infections and, thus, should be considered for Ig or antibiotic prophylaxis.