Prognostic markers in chronic lymphocytic leukemia: A comprehensive review

Complex evaluation of serum immunoglobulin levels in patients with chronic lymphocytic leukemia: Significant increase in IgA after first-line chemoimmunotherapy

INTRODUCTION

The impact of chemoimmunotherapy (CIT) on immunoglobulin (Ig) quantities in patients with chronic lymphocytic leukemia (CLL) has not been extensively studied.

METHODS

We analyzed Ig levels in 45 stable patients with indolent CLL (without indication for treatment) and 87 patients with progressive disease before first-line treatment. Fifty-five patients were evaluated again after the treatment with CIT.

RESULTS

We observed significantly lower levels of all Ig classes and subclasses in patients with progressive disease compared to patients with indolent disease. After treatment, median IgA increased from 0.59 g/L to 0.74 g/L (p = 0.0031). In stable patients, lower IgA2 was associated with shorter time to first treatment, although it did not reach statistical significance (p = 0.056). Shorter overall survival was observed in patients with progressive disease and lower IgG2 (p = 0.043). Surprisingly, among the patients with progressive CLL, unmutated IGHV genes were associated with higher levels of IgG, IgG1 and IgM, while TP53 mutation and/or 17p deletion were associated with higher levels of IgA and IgA1.

CONCLUSIONS

CIT may lead to increase in IgA levels. Hypogammaglobulinemia is more common in patients with progressive CLL and unmutated IGHV or TP53 dysfunction.

Advances in Monitoring and Prognostication for Lymphoma by Flow Cytometry

Flow cytometry (FC) is a well-established method important in the diagnosis and subclassification of lymphoma. In this article, the role of FC in lymphoma prognostication will be explored, and the clinical role for FC minimal/measurable residual disease testing as a monitoring tool for mature lymphoma will be introduced. Potential pitfalls of monitoring for residual/recurrent disease following immunotherapy will be presented.

Circular RNA Expression Signatures Provide Promising Diagnostic and Therapeutic Biomarkers for Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is a known hematologic malignancy associated with a growing incidence and post-treatment relapse. Hence, finding a reliable diagnostic biomarker for CLL is crucial. Circular RNAs (circRNAs) represent a new class of RNA involved in many biological processes and diseases. This study aimed to define a circRNA-based panel for the early diagnosis of CLL. To this point, the list of the most deregulated circRNAs in CLL cell models was retrieved using bioinformatic algorithms and applied to the verified CLL patients' online datasets as the training cohort (n = 100). The diagnostic performance of potential biomarkers represented in individual and discriminating panels, was then analyzed between CLL Binet stages and validated in individual sample sets I (n = 220) and II (n = 251). We also estimated the 5-year overall survival (OS), introduced the cancer-related signaling pathways regulated by the announced circRNAs, and provided a list of possible therapeutic compounds to control the CLL. These findings show that the detected circRNA biomarkers exhibit better predictive performance compared to current validated clinical risk scales, and are applicable for the early detection and treatment of CLL.

Secondary involvement of gallbladder by acute lymphoblastic leukemia presenting clinically as cholecystitis in a young patient: a case report

BACKGROUND

Primary lymphoma of the liver, gallbladder, and extrahepatic bile ducts or secondary involvement of these organs by leukemia is exceedingly rare. Patients with primary lymphoma or leukemic involvement of the biliary tract and liver often present with symptoms and signs of biliary tract obstruction or inflammation.

CASE PRESENTATION

We present a case of a 24-year-old male with biliary tract symptoms who underwent laparoscopic cholecystectomy. His precholecystectomy complete blood count performed on the same morning showed 72% lymphocytes while peripheral blood smears showed approximately 15% blasts. Surgeon went ahead with the procedure. Imaging done prior to surgery showed thickened gallbladder, while the liver, biliary tract, and pancreas did not show any thickening or mass lesion. However, the liver was enlarged. Grossly, the gallbladder wall did not show any stones or discrete mass involving the wall. Instead, there was subtle thickening of the gallbladder wall due to diffuse infiltration by the leukemic infiltrate. This lymphoid population reacted with PAX-5 and TdT immunohistochemical antibodies in a diffuse manner confirming precursor B-cell origin. This patient was found to have B-lymphoblastic leukemia involving his bone marrow on further clinical and diagnostic workup. Patient responded well to chemotherapy and is currently on maintenance treatment. He is well 1.5 years after his diagnosis.

CONCLUSION

This case highlights a unique and rare scenario where a previously undiagnosed and unsuspected hematologic malignancy initially presented with clinical features of a chronic inflammatory condition involving an abdominal organ owing to secondary involvement by the malignant infiltrate.

Examining Treatment Patterns and Real-World Outcomes in Chronic Lymphocytic Leukemia Using Administrative Data in Ontario

Information on the real-world experience of Canadians diagnosed with chronic lymphocytic leukemia (CLL) is limited. This study was conducted to report treatment patterns and outcomes of CLL using Ontario administrative data. A retrospective cohort study was conducted in patients diagnosed with CLL between 1 January 2010 and 31 December 2017 identified in the Ontario Cancer Registry (OCR). Data were accessed using the Institute of Clinical Evaluative Sciences (ICES), which collects various population-level health information. In the Ontario Cancer Registry, 2887 CLL patients receiving treatment and diagnosed between 2010–2017 were identified. Fludarabine, cyclophosphamide and rituximab (FCR) chemoimmunotherapy was most frequently used as a first line, but use declined since ibrutinib and obinutuzumab combinations were funded in 2015. In patients treated with frontline FCR, survival at year one was 89% pre-2015 and 96% post-2015; at year four, survival was 73% and 87%, respectively. Survival in patients treated with frontline chlorambucil was 76% pre-2015 and 75% post-2015 in year 1, and 45% and 56% in year 3. Our analysis shows that, as the treatment landscape for CLL has shifted, use of newer and novel agents as a first line or earlier in the relapsed/refractory setting has resulted in improved survival outcomes.

Importance of Crosstalk Between Chronic Lymphocytic Leukemia Cells and the Stromal Microenvironment: Direct Contact, Soluble Factors, and Extracellular Vesicles

Chronic lymphocytic leukemia (CLL) is caused by the accumulation of malignant B cells due to a defect in apoptosis and the presence of small population of proliferating cells principally in the lymph nodes. The abnormal survival of CLL B cells is explained by a plethora of supportive stimuli produced by the surrounding cells of the microenvironment, including follicular dendritic cells (FDCs), and mesenchymal stromal cells (MSCs). This crosstalk between malignant cells and normal cells can take place directly by cell-to-cell contact (assisted by adhesion molecules such as VLA-4 or CD100), indirectly by soluble factors (chemokines such as CXCL12, CXCL13, or CCL2) interacting with their receptors or by the exchange of material (protein, microRNAs or long non-coding RNAs) via extracellular vesicles. These different communication methods lead to different activation pathways (including BCR and NFκB pathways), gene expression modifications (chemokines, antiapoptotic protein increase, prognostic biomarkers), chemotaxis, homing in lymphoid tissues and survival of leukemic cells. In addition, these interactions are bidirectional, and CLL cells can manipulate the normal surrounding stromal cells in different ways to establish a supportive microenvironment. Here, we review this complex crosstalk between CLL cells and stromal cells, focusing on the different types of interactions, activated pathways, treatment strategies to disrupt this bidirectional communication, and the prognostic impact of these induced modifications.

Monoclonal gammopathy and serum immunoglobulin levels as prognostic factors in chronic lymphocytic leukaemia

The relationship between chronic lymphocytic leukaemia (CLL) and qualitative/quantitative gammaglobulin abnormalities is well established. Nevertheless, in order to better understand this kind of connection, we examined 1505 patients with CLL and divided them into four subgroups on the basis of immunoglobulin (Ig) aberrations at diagnosis. A total of 73 (4·8%), 149 (10%), 200 (13·2%) and 1083 (72%) patients were identified with IgM monoclonal gammopathy (IgM/CLL), IgG monoclonal gammopathy (IgG/CLL), hypogammaglobulinaemia (hypo-γ) and normal Ig levels (γ-normal) respectively. IgM paraprotein was significantly associated with a more advanced Binet/Rai stage and del(17p)/TP53 mutation, while IgG abnormalities correlated with a higher occurrence of trisomy 12. Patients with any type of Ig abnormality had shorter treatment-free survival (TFS) but no significant impact affecting overall survival (OS) compared to those with normal Ig levels.

Mitochondrial Respiration Correlates with Prognostic Markers in Chronic Lymphocytic Leukemia and Is Normalized by Ibrutinib Treatment

Mitochondrial bioenergetics profiling, a measure of oxygen consumption rates, correlates with prognostic markers and can be used to assess response to therapy in chronic lymphocytic leukemia (CLL) cells. In this study, we measured mitochondrial respiration rates in primary CLL cells using respirometry to evaluate mitochondrial function. We found significant increases in mitochondrial respiration rates in CLL versus control B lymphocytes. We also observed amongst CLL patients that advanced age, female sex, zeta-chain-associated protein of 70 kD (ZAP-70⁺), cluster of differentiation 38 (CD38⁺), and elevated β2-microglobulin (β2-M) predicted increased maximal respiration rates. ZAP-70⁺ CLL cells exhibited significantly higher bioenergetics than B lymphocytes or ZAP-70⁻ CLL cells and were more sensitive to the uncoupler, carbonyl cyanide-p-trifluoro-methoxyphenylhydrazone (FCCP). Univariable and multivariable linear regression analysis demonstrated that ZAP-70⁺ predicted increased maximal respiration. ZAP-70⁺ is a surrogate for B cell receptor (BCR) activation and can be targeted by ibrutinib, which is a clinically approved Bruton’s tyrosine kinase (BTK) inhibitor. Therefore, we evaluated the oxygen consumption rates (OCR) of CLL cells and plasma chemokine (C-C motif) ligands 3 and 4 (CCL3/CCL4) levels from ibrutinib-treated patients and demonstrated decreased OCR similar to control B lymphocytes, suggesting that ibrutinib treatment resets the mitochondrial bioenergetics, while diminished CCL3/CCL4 levels indicate the down regulation of the BCR signaling pathway in CLL. Our data support evaluation of mitochondrial respiration as a preclinical tool for the response assessment of CLL cells.

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.

Mutational and cytogenetic analyses of 188 CLL patients with trisomy 12: A retrospective study from the French Innovative Leukemia Organization (FILO) working group

Trisomy 12 (tri12) is the second most frequent chromosomal aberration (15%-20%) in chronic lymphocytic leukemia (CLL). Tri12 confers an intermediate prognosis but is a heterogeneous entity. We examined whether additional mutational or chromosomal alterations might impact tri12 patient outcomes. This retrospective study, carried out by the French Innovative Leukemia Organization, included 188 tri12 patients with comprehensive information on immunoglobulin heavy chain (IGHV) gene status, karyotypic/FISH abnormalities, and NOTCH1, TP53, SF3B1, and MYD88 mutations. The main cytogenetic abnormalities associated with tri12 were del(13q) (25%), additional trisomies (14%) (including tri19 (10%) and tri18 (4%)), 14q32 translocations (10%), del(17p) (6.5%), del(14q) (4%), and del(11q) (4%). Unmutated (UM) IGHV, NOTCH1, and TP53, mutations were identified in respectively 66%, 25%, and 8.5% of cases. Multivariate analyses showed that additional trisomies (HR = 0.43, 95% CI = 0.23-0.78, P = .01) were associated with a significantly longer time to first treatment in Binet stage A patients and with a lower risk of relapse (HR = 0.37, 95% CI = 0.15-0.9, P = .03) in the overall tri12 population. Binet stage B/C, TP53 disruption, and UM IGHV status were associated with a shorter time to next treatment, while Binet stage B/C (HR = 4, 95% CI = 1.6-4.9, P = .002) and TP53 disruption (HR = 5, 95% CI = 1.94-12.66, P = .001) conferred shorter overall survival in multivariate comparisons. These data indicate that additional cytogenetic and mutational abnormalities, and particularly additional trisomies, IGHV status, and TP53 disruption, influence tri12 patient outcomes and could improve risk stratification in this population.

Guidelines for Diagnosis and Treatment of Chronic Lymphocytic Leukemia. Krohem B-Cll 2017

Recent developments in the diagnosis and treatment of chronic lymphocytic leukemia (B-CLL) have led to change of approach in clinical practice. New treatments have been approved based on the results of randomized multicenter trials for first line and for salvage therapy, and the results of numerous ongoing clinical trials are permanently providing new answers and further refining of therapeutic strategies. This is paralleled by substantial increase in understanding the disease genetics due to major advances in the next generation sequencing (NGS) technology. We define current position of the Croatian Cooperative Group for Hematologic Disease on diagnosis and treatment of CLL in the transition from chemo-immunotherapy paradigm into a new one that is based on new diagnostic stratification and unprecedented therapeutic results of B-cell receptor inhibitors (BRI) and Bcl-2 antagonists. This is a rapidly evolving field as a great number of ongoing clinical trials con-stantly accumulate and provide new knowledge. We believe that novel therapy research including genomic diagnosis is likely to offer new options that will eventually lead to time limited therapies without chemotherapy and more effective clinical care for B-CLL based on individualized precision medicine.

Antibodies against Pneumococcal Capsular Polysaccharides and Natural Anti-Galactosyl (Alpha-Gal) in Patients with Humoral Immunodeficiencies

Humoral deficiencies represent a broad group of disorders. The aim of the study was to compare the levels of antibodies against pneumococcal capsular polysaccharides (anti-PCP) and natural anti-galactosyl (anti-Gal) antibodies in (1) patients with chronic lymphocytic leukaemia (CLL), (2) patients with common variable immunodeficiency (CVID), and (3) a healthy population and to explore their diagnostic and prognostic potential. Serum immunoglobulin levels and levels of anti-Gal IgG, IgA, and IgM and anti-PCP IgG and IgG2 were determined in 59 CLL patients, 30 CVID patients, and 67 healthy controls. Levels of IgG, IgA, IgM, anti-Gal IgA, anti-Gal IgM, and anti-PCP IgA were lower in CLL and CVID patients than in healthy controls (p value for all parameters < 0.0001). Decrease in the levels of IgA, IgM, anti-Gal IgA, and anti-PCP IgA was less pronounced in the CLL group than in the CVID group. IgA decline, anti-Gal IgA, anti-PCP IgA, and anti-PCP IgG2 were negatively correlated with CLL stage. We devise the evaluation of anti-Gal antibodies to be a routine test in humoral immunodeficiency diagnostics, even in cases of immunoglobulin substitution therapy. Significant reductions, mainly in anti-Gal IgA, IgM, and anti-PCP IgA levels, may have prognostic importance in CLL patients.

Characterization of TET and IDH gene expression in chronic lymphocytic leukemia: comparison with normal B cells and prognostic significance

BACKGROUND

Chronic lymphocytic leukemia (CLL) is the most common hematological malignancy in western countries, characterized by a heterogeneous clinical course. Although genetic studies have identified chromosomal aberrations or specific mutations, epigenetic changes have been poorly characterized in CLL.

METHODS

We assessed ten-eleven translocations (TET) 1, 2, and 3, isocitrate dehydrogenase (IDH) 1, and 2 messenger RNA (mRNA) expression using real-time PCR on purified leukemic B cells from 214 CLL patients (median follow-up = 75 months, range 1-380), normal peripheral blood B cells (n = 20), and umbilical cord blood B cells (n = 21). The microenvironment influence was assessed after 24 h co-culture of CLL cells with bone marrow mesenchymal stromal cells (BMSC). Finally, 5-hydroxymethylcytosine level (%5-hmC) was assessed by ELISA in CLL cells alone or with microenvironment stimuli.

RESULTS

TET 1 and 3 and IDH2 were decreased in CLL cells compared with healthy B cells (P = 0.0221, 0.0013, <0.0001, respectively), while IDH1 was overexpressed (P = 0.0037). TET2 and IDH1 were significantly correlated with treatment-free survival (TFS); patients with high TET2/IDH1 expression had a higher median TFS (111 months) than patients with low expression (78 months, P = 0.0071/0.0123). Moreover, TET1 expression decreased (P = 0.0371), while TET3 and IDH2 expression increased (P = 0.0273/0.0039) in co-cultures. However, %5-hmC was not correlated with clinical data and was unchanged following microenvironment stimuli.

CONCLUSIONS

Despite a slight deregulation in CLL cells compared with normal B cells, we identified a significant association between TET/IDH gene expression and prognosis, suggesting that epigenetic changes could potentially be associated with disease progression. Moreover, despite an identical %5-hmC, TET gene expression was influenced by contact with BMSC confirming the crucial role of the microenvironment in CLL pathogenesis.

Lipoprotein lipase in chronic lymphocytic leukemia: function and prognostic implications

Chronic lymphocytic leukemia (CLL) is a clinically heterogeneous disease characterized by the accumulation of a clonal population of B cells in peripheral blood, bone marrow, and lymphoid organs. More than 10 years ago, lipoprotein lipase (LPL) mRNA was identified as being strongly expressed in patients experiencing a more aggressive phenotype, while CLL patients with an indolent disease course lack expression of this marker. Since then, several reports confirmed the capability of LPL to predict CLL disease evolution at the moment of diagnosis. In contrast, data on the functional implications of LPL in CLL are scarce. LPL exerts a central role in overall lipid metabolism and transport, but plays additional, non-catalytic roles as well. Which of those is more important in the pathogenesis of CLL remains largely unclear. Here, we review the current knowledge on the prognostic and biological relevance of LPL in CLL.

Key Molecular Drivers of Chronic Lymphocytic Leukemia

Chronic lymphocytic leukemia (CLL) is an adult neoplastic disease of B cells characterized by variable clinical outcomes. Although some patients have an aggressive form of the disease and often encounter treatment failure and short survival, others have more stable disease with long-term survival and little or no need for theraphy. In the past decade, significant advances have been made in our understanding of the molecular drivers that affect the natural pathology of CLL. The present review describes what is known about these key molecules in the context of their role in tumor pathogenicity, prognosis, and therapy.

IRF-3 gene polymorphisms are associated with the susceptibility to and the survival in chronic lymphocytic leukemia and could also serve as an auxiliary index

The objective of this article was to investigate the relationship between IRF-3 gene polymorphisms and the susceptibility and prognosis of CLL. Between January 2011 and August 2012, 108 CLL patients and 112 healthy were enrolled in the study. DHPLC and Shesis software were applied in our study. In rs7251, CG genotype may increase the CLL risk. In the rs2304206, the alleles T may increase the CLL risk. The GTC haplotype can decrease the CLL risk in normal people, the GTT haplotype can increase the CLL risk in normal people. After treatment, in the rs7251, the event-free survival (EFS) in patients carrying CC genotype was higher than those carrying CG + GG genotype. In the rs2304206, the EFS in patients carrying CC genotype was higher than those carrying CT + TT genotype. IRF-3 gene polymorphisms were associated with the susceptibility and prognosis of CLL, it can be used as an auxiliary index for clinical detection of CLL.

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.

Immunoglobulin gene translocations in chronic lymphocytic leukemia: A report of 35 patients and review of the literature

Chronic lymphocytic leukemia (CLL) represents the most common hematological malignancy in Western countries, with a highly heterogeneous clinical course and prognosis. Translocations involving the immunoglobulin (IG) genes are regularly identified. From 2000 to 2014, we identified an IG gene translocation in 18 of the 396 patients investigated at diagnosis (4.6%) and in 17 of the 275 analyzed during follow-up (6.2%). A total of 4 patients in whom the IG translocation was identified at follow-up did not carry the translocation at diagnosis. The IG heavy locus (IGH) was involved in 27 translocations (77.1%), the IG κ locus (IGK) in 1 (2.9%) and the IG λ locus (IGL) in 7 (20.0%). The chromosome band partners of the IG translocations were 18q21 in 16 cases (45.7%), 11q13 and 19q13 in 4 cases each (11.4% each), 8q24 in 3 cases (8.6%), 7q21 in 2 cases (5.7%), whereas 6 other bands were involved once (2.9% each). At present, 35 partner chromosomal bands have been described, but the partner gene has solely been identified in 10 translocations. CLL associated with IG gene translocations is characterized by atypical cell morphology, including plasmacytoid characteristics, and the propensity of being enriched in prolymphocytes. The IG heavy chain variable region (IGHV) mutational status varies between translocations, those with unmutated IGHV presumably involving cells at an earlier stage of B-cell lineage. All the partner genes thus far identified are involved in the control of cell proliferation and/or apoptosis. The translocated partner gene becomes transcriptionally deregulated as a consequence of its transposition into the IG locus. With the exception of t(14;18)(q32;q21) and its variants, prognosis appears to be poor for the other translocations. Therefore, searching for translocations involving not only IGH, but also IGL and IGK, by banding and molecular cytogenetics is required. Furthermore, it is important to identify the partner gene to ensure the patients receive the optimal treatment.

Residual expression of SMYD2 and SMYD3 is associated with the acquisition of complex karyotype in chronic lymphocytic leukemia

SET and MYND domain containing 2 (SMYD2) and the SET and MYND domain containing 3 (SMYD3) are the most studied and well-characterized members of SMYD family. It has been demonstrated that their altered expression is associated with the progression of several solid tumors. Nevertheless, whether these methyltransferases exert any impact in chronic lymphocytic leukemia (CLL) remains unknown. Here, we investigated the gene expression profile of SMYD2 and SMYD3 in 59 samples of CLL and 10 normal B cells. The obtained results were associated with white blood cells (WBC) and platelet counts, ZAP-70 protein expression, and cytogenetic analysis. We found that SMYD2 and SMYD3 are overexpressed in CLL patients and, interestingly, patients with residual expression of both genes presented a high WBC count and complex karyotype. Furthermore, a strong correlation between SMYD2 and SMYD3 gene expression was unveiled. Our data demonstrate the association of a residual expression of SMYD2 and SMYD3 with CLL progression indicators and suggests both genes are regulated by a common transcriptional control in this type of cancer. These results may provide the basis for the development of new therapeutic strategies to prevent CLL progression.

miR-377-dependent BCL-xL regulation drives chemotherapeutic resistance in B-cell lymphoid malignancies

Background

BCL-xL is an anti-apoptotic BCL-2 family protein that inhibits apoptosis and is overexpressed in many cancers. We have reported that acquired resistance to the BCL-2 inhibitor ABT-199 (venetoclax) is associated with increased BCL-xL expression. Yet, how BCL-xL mediates chemoresistance in hematopoietic malignancies is not clear. This finding may help in design of new strategies for therapeutic intervention to overcome acquired chemoresistance mediated by BCL-xL.

Results

We now show that the increased BCL-xL expression was inversely correlated with that of miR-377 in ABT-199-resistant cells. This finding was also extended to a panel of B-cell lymphoid lines and primary chronic lymphocytic leukemia (CLL) cells. miR-377 suppressed BCL-xL expression by recognizing two binding sites in the BCL-xL 3’-UTR. Mutation of these two miR-377 consensus-binding sites completely abolished its regulatory effect. Expression of a miR-377 mimic downregulated BCL-xL protein expression and significantly increased apoptotic cell death. Expression of a miR-377 inhibitor restored BCL-xL protein expression and limited cell death caused by the hypomethylating agent 5-azacytidine. Thus, miR-377-dependent BCL-xL regulation drives acquired therapeutic resistance to ABT-199. We further show that CLL patients who received a diverse array of chemotherapy regimens also had significantly higher BCL-xL and lower miR377 expression, indicating that exposure to chemotherapy might trigger transcriptional silencing of miR-377, which results in high levels of BCL-xL. Importantly, CLL patients with high BCL-xL/low miR-377 expression had an advanced tumor stage. Moreover, the high BCL-xL expression correlated with short treatment-free survival in 76 CLL patients. miR-377 is located at 14q32 in the DLK1-DIO3 region, which encodes the largest tumor suppressor miRNA cluster in humans. Examination of five additional 14q32 miRNAs revealed that the majority were significantly down-regulated in most CLL patients as well as in ABT-199-resistant cell lines. Remarkably, four of these miRNAs had significantly decreased expression in chemotherapy-treated CLL patients as compared to those untreated. These findings indicate a reduced expression of multiple miRNAs that may reflect a global silencing of this miRNA cluster in therapy-resistant lymphoid cells.

Conclusions

These findings reveal a novel mechanism by which down-regulation of miR-377 increases BCL-xL expression, promoting chemotherapy resistance in B-cell lymphoid malignancies.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0460-8) contains supplementary material, which is available to authorized users.

Incidence of chromosomal anomalies detected by interphase FISH in chronic lymphoid leukemia

Aims & methods: We used interphase FISH to determine the incidence of chromosomal changes in 638 B-cell chronic lymphocytic leukemia patients. Results: Chromosomal abnormalities were found in some 75% of the patients. Del(13)(q14) was present in 57.3 and 57% of patients at diagnosis and during follow-up, respectively. It was followed by trisomy 12 (19 and 19.8% at diagnosis and during follow-up, respectively), del(11)(q22) (9.1 and 14.3% at diagnosis and during follow-up, respectively) and del(17)(p13) (2.8 and 12.4% at diagnosis and during follow-up, respectively). Discussion & conclusion: Our results correlate with those obtained in 55 studies reported in the literature. Trisomy 12 and del(13)(q14) are present in high proportions at diagnosis and are not enriched during progression, to the contrary of del(11)(q22) and del(17)(p13) that are markers of evolution.

TLR-9 and IL-15 Synergy Promotes the In Vitro Clonal Expansion of Chronic Lymphocytic Leukemia B Cells

Clinical progression of B cell chronic lymphocytic leukemia (B-CLL) reflects the clone's Ag receptor (BCR) and involves stroma-dependent B-CLL growth within lymphoid tissue. Uniformly elevated expression of TLR-9, occasional MYD88 mutations, and BCR specificity for DNA or Ags physically linked to DNA together suggest that TLR-9 signaling is important in driving B-CLL growth in patients. Nevertheless, reports of apoptosis after B-CLL exposure to CpG oligodeoxynucleotide (ODN) raised questions about a central role for TLR-9. Because normal memory B cells proliferate vigorously to ODN+IL-15, a cytokine found in stromal cells of bone marrow, lymph nodes, and spleen, we examined whether this was true for B-CLL cells. Through a CFSE-based assay for quantitatively monitoring in vitro clonal proliferation/survival, we show that IL-15 precludes TLR-9-induced apoptosis and permits significant B-CLL clonal expansion regardless of the clone's BCR mutation status. A robust response to ODN+IL-15 was positively linked to presence of chromosomal anomalies (trisomy-12 or ataxia telangiectasia mutated anomaly + del13q14) and negatively linked to a very high proportion of CD38(+) cells within the blood-derived B-CLL population. Furthermore, a clone's intrinsic potential for in vitro growth correlated directly with doubling time in blood, in the case of B-CLL with Ig H chain V region-unmutated BCR and <30% CD38(+) cells in blood. Finally, in vitro high-proliferator status was statistically linked to diminished patient survival. These findings, together with immunohistochemical evidence of apoptotic cells and IL-15-producing cells proximal to B-CLL pseudofollicles in patient spleens, suggest that collaborative ODN and IL-15 signaling may promote in vivo B-CLL growth.

Global histone deacetylase enzymatic activity is an independent prognostic marker associated with a shorter overall survival in chronic lymphocytic leukemia patients

Histone deacetylases (HDAC) play a crucial role in transcriptional regulation and are often deregulated in many cancers. However, global HDAC enzymatic activity has never been investigated in Chronic Lymphocytic Leukemia (CLL). We measured HDAC activity in protein extracts from CD19+ B-cells purified from 114 CLL patients with a median follow-up of 91 months (range: 11-376). HDAC activity was equivalent in CLL and normal B-cells but higher in patients who died during the study than in living patients (152.1 vs. 65.04 pmol; P = 0.0060). Furthermore, HDAC activity correlated with treatment-free survival (TFS; P = 0.0156) and overall survival (OS; P < 0.0001): patients with low HDAC activity (n = 75) had a median TFS and OS of 101 and > 376 months, respectively, whereas patients with high HDAC activity (n = 39) had a median TFS and OS of 47 and 137 months, respectively. Multivariate analyses indicated that HDAC activity is an independent predictor of OS (hazard ratio = 7.68; P = 0.0017). Finally, HDAC activity increased after B-cell receptor stimulation using IgM, suggesting a role for microenvironment stimuli (n = 10; P = 0.0371). In conclusion, high HDAC activity in CLL B-cells is associated with shorter TFS and OS and is an independent marker of OS, refining the use of other prognostic factors. This work provides a biological base for the use of HDAC inhibitors in CLL treatment.

Opposite Prognostic Significance of Cellular and Serum Circulating MicroRNA-150 in Patients with Chronic Lymphocytic Leukemia

MicroRNAs (or miRs) play a crucial role in chronic lymphocytic leukemia (CLL) physiopathology and prognosis. In addition, circulating microRNAs in body fluids have been proposed as new biomarkers. We investigated the expression of matched cellular and serum circulating microRNA-150 by quantitative real-time PCR (qPCR) from purified CD19(+) cells or from CLL serums obtained at diagnosis in a cohort of 273/252 CLL patients with a median follow-up of 78 months (range 7-380) and correlated it to other biological or clinical parameters. We showed that miR-150 was significantly overexpressed in CLL cells/serums compared with healthy subjects (P < 0.0001). Among CLL patients, a low cellular miR-150 expression level was associated with tumor burden, disease aggressiveness and poor prognostic factors. In contrast, a high level of serum miR-150 was associated with tumor burden markers and some markers of poor prognosis. Similarly, cellular and serum miR-150 also predicted treatment-free survival (TFS) and overall survival (OS) in an opposite manner: patients with low cellular/serum miR-150 levels have median TFS of 40/111 months compared with high-level patients who have a median TFS of 122/60 months (P < 0.0001/P = 0.0066). Similar results were observed for OS. We also found that cellular and serum miR-150 levels vary in an opposite manner during disease progression and that cellular miR-150 could be regulated by its release into the extracellular space. Cellular and serum levels of miR-150 are associated with opposite clinical prognoses and could be used to molecularly monitor disease evolution as a new prognostic factor in CLL.

Prognostic information and biological insights in chronic lymphocytic leukemia by high-resolution immunophenotypic analysis of ZAP70

The E2997 Phase III trial included preservation of valuable chronic lymphocytic leukemia (CLL) patient specimens and relevant clinical outcome data. Using a novel high-resolution technology on a flow cytometry platform, we assessed 79 E2997 samples for the expression of 27 analytes that reflected the activity of signaling pathways and apoptosis. We found that the expression levels of ZAP70 segregated the samples into two subpopulations with the distribution showing a peak-trough-peak configuration. Although prior assessment of ZAP70 by standard procedures did not reveal any prognostic information, we found by using the trough in the distribution as a cutpoint that ZAP70 expression levels were significantly correlated with both progression-free survival and overall survival. Additionally, the cells expressing high versus low levels of ZAP70 demonstrated distinct molecular organization as indicated by the other analytes assessed. Our analysis demonstrates the value of ZAP70 expression as a prognostic indicator and suggests that the different clinical results may be due to the distinct molecular biology of the ZAP70-low versus the ZAP70-high CLL samples.

IgM peak independently predicts treatment-free survival in chronic lymphocytic leukemia and correlates with accumulation of adverse oncogenetic events

We examined the significance of IgM peaks in chronic lymphocytic leukemia (CLL), including its association with newly reported MYD88, BIRC3, NOTCH1 and SF3B1 mutations. A total of 27, 25, 41 and 57 patients with monoclonal IgM or IgG peaks (IgM and IgG groups), hypogammaglobulinemia (Hypo-γ group) and normal immunoglobulin serum levels (normal-γ group) were, respectively, included. IgM peaks were mainly associated with Binet stage C and the del(17p). Biased usage of IGHV3-48 was shared by both IgM and IgG groups. IGHV3-74 and IGHV4-39 gene rearrangements were specific for IgM and IgG peaks, respectively. SF3B1, NOTCH1, MYD88 and BIRC3 mutation frequencies were 12%, 4%, 2% and 2%, respectively, being over-represented in IgM, IgG and Hypo-γ groups for SF3B1, and being equal between normal-γ and IgM groups for MYD88. Overall, 76%, 87%, 49% and 42% of cases from IgM, IgG, Hypo-γ and normal-γ groups had at least one intermediate or poor prognosis genetic marker, respectively. By multivariate analysis, IgM peaks were associated with shorter treatment-free survival independently from any other univariate poor prognosis biological parameters, including IgG peaks, Hypo-γ, IGHV status, SF3B1 mutations, cytogenetics and lymphocytosis. Therefore, as with IgG peaks, IgM peaks aggravated the natural course of CLL, with increased accumulation of adverse genetic events.

Five important advances in hematopathology

CONTEXT

Hematopathology is a dynamic field that has always been on the frontier of clinical research within the scope of pathology. Several recent developments in hematopathology will likely affect its practice clinically.

OBJECTIVE

To review 5 important recent advances in hematopathology: (1) detection and prognostic implication of MYC in diffuse large B-cell lymphomas, (2) determining origin and prognosis through immunoglobulin gene usage in mature B-cell neoplasms, (3)detecting minimal residual disease in multiple myeloma, (4) using genome-wide analysis in myelodysplastic syndromes, and (5) employing whole-genome sequencing in acute myeloid leukemias.

DATA SOURCES

Literature review and the authors' experiences in an academic center.

CONCLUSIONS

These advances will bring hematopathology into a new molecular era and help us to better understand the molecular, pathologic mechanisms of lymphomas, leukemias, myelomas, and myelodysplastic syndromes. They will help us to identify diagnostic and prognostic markers and eventually provide new therapeutic targets and treatments for these diseases.

Very low levels of surface CD45 reflect CLL cell fragility, are inversely correlated with trisomy 12 and are associated with increased treatment-free survival

It has recently been suggested that the percentage of smudge cells on blood smears from patients with chronic lymphocytic leukemia (CLL) could predict overall survival. However, smudge cells are a cytological artifact influenced by multiple physical factors not related to CLL. To identify simple parameters reflecting CLL cell fragility, we studied CD45 expression in a series of 66 patients with Binet stage A CLL. Decreased CD45 expression was specific for CLL cells when compared to 44 patients with a leukemic phase of B-cell non Hodgkin lymphoma and 42 control B-cells. CD45 expression was markedly decreased for all patients with CLL with high percentages of smudge cells. CLL cells with the lowest CD45 expression were the most sensitive to osmotic shock. Very low levels of CD45 expression were significantly associated with lack of CD38 expression, absence of trisomy 12, and with increased treatment free survival time. Altogether, these results demonstrate that low levels of CD45 expression are specific to CLL cells and reflect cell fragility, suggesting that this is an important intrinsic biological feature that determines disease course.

Short telomere length is associated with NOTCH1/SF3B1/TP53 aberrations and poor outcome in newly diagnosed chronic lymphocytic leukemia patients

Most previous studies on telomere length (TL) in chronic lymphocytic leukemia (CLL) are based on referral cohorts including a high proportion of aggressive cases. Here, the impact of TL was analyzed in a population-based cohort of newly diagnosed CLL (n = 265) and in relation to other prognostic markers. Short telomeres were particularly associated with high-risk genetic markers, such as NOTCH1, SF3B1, or TP53 aberrations, and predicted a short time to treatment (TTT) and overall survival (OS) (both P < 0.0001). TL was an independent prognostic factor and subdivided patients with otherwise good-prognostic features (e.g., mutated IGHV genes, favorable cytogenetics) into subgroups with different outcome. Furthermore, in follow-up samples (n = 119) taken 5-8 years after diagnosis, TL correlated well with TL at diagnosis and remained unaffected by treatment. Altogether, these novel data indicate that short TL already at diagnosis is associated with poor outcome in CLL and that TL can be measured at later stages of the disease.

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.

Diagnostic and clinical considerations in concomitant bone marrow involvement by plasma cell myeloma and chronic lymphocytic leukemia/monoclonal B-cell lymphocytosis: a series of 15 cases and review of literature

CONTEXT

Plasma cell myeloma and chronic lymphocytic leukemia are both common hematologic malignancies, sharing many epidemiologic features. Concomitant detection of the 2 conditions poses special diagnostic challenges for the pathologist.

OBJECTIVE

To describe the pathologic findings in cases of concomitant bone marrow involvement by myeloma and CD5(+) monoclonal B cells and to outline the differential diagnostic possibilities, suggest a workup for correct diagnosis, and examine clinical outcome.

DESIGN

Fifteen cases that met the diagnostic criteria were identified from pathology databases at 4 participating institutions. Morphologic findings were reviewed, additional immunohistochemical stains performed, and flow cytometric, cytogenetic, and relevant laboratory and clinical information was summarized. Previously published cases were searched from electronic databases and cross-references.

RESULTS

Most patients (13 of 15) were older males. Often (11 of 15) they presented clinically with myeloma, yet had both monotypic plasma cells and B cells in the diagnostic marrow. In 4 patients, myeloma developed 24 months or later after chronic lymphocytic leukemia. In 7 patients, myeloma and CD5(+) B cells showed identical immunoglobulin light-chain restriction. Primary differential diagnoses include lymphoplasmacytic lymphoma, marginal zone lymphoma, and chronic lymphocytic leukemia with plasmacytoid differentiation. CD56 and/or cyclin D1 expression by plasma cells was helpful for correct diagnosis. Most patients in our cohort and published reports were treated for plasma cell myeloma.

CONCLUSIONS

Concomitant detection of myeloma and chronic lymphocytic leukemia in the bone marrow is a rare event, which must be carefully differentiated from lymphomas with lymphoplasmacytic differentiation for correct treatment.

Chronic lymphoproliferative disorders at an Indian tertiary cancer centre - the panel sufficiency in the diagnosis of chronic lymphocytic leukaemia

BACKGROUND

Flow cytometry has come to occupy the vanguard of the high through put diagnostic techniques that have been used to differentiate between various chronic lymphoproliferative disorders (CLPD). However, economic considerations have created the need for minimal consensus panels that can yield maximum information at reasonable costs.

AIMS

To collect, analyse and correlate the morphologic, immunophenotypic, and the cytogenetic data from the cases of chronic lymphoproliferative disorders, which were diagnosed at an Indian speciality cancer centre.

METHODS AND MATERIAL

The morphology was recorded after staining the samples with the Leishman or the MGG stains. The lineage assignment was done by using three colour flow cytometry with a primary panel of antibodies. For the cytogenetic studies, the short term culture of the sample cells were arrested by using colcemid and they were G-banded by using trypsin and Giemsa stain. FISH studies were conducted by using a CLL-specific diagnostic kit.

RESULTS AND CONCLUSIONS

A total of 66 cases were evaluated, which had a median age of 64.5 years and a sex ratio of 2.3:1. Of these 66 cases, 40 cases were of CLL and 9 cases were of atypical CLL. 17 cases were classified as CLPD and these included 13 cases of Non-Hodgkin's Lymphoma, two cases of Hairy Cell Leukaemia, one case of Follicular Lymphoma and one case of Prolymphocytic Leukaemia. In immunophenotyping, the lack of expression of CD22 had the highest correlation with a definitive diagnosis of CLL. Cytogenetics demonstrated a classical follicular lymphoma abnormality, t (14; 18) (q32; q21), in one case. A basic minimal panel is sufficient for the routine diagnosis of CLL. However, the stratification of CLPD requires the use of more extensive panels.

Clonal evolution, genomic drivers, and effects of therapy in chronic lymphocytic leukemia

PURPOSE

The identification of gene mutations and structural genomic aberrations that are critically involved in chronic lymphocytic leukemia (CLL) pathogenesis is still evolving. One may postulate that genomic driver lesions with effects on CLL cell proliferation, apoptosis thresholds, or chemotherapy resistance should increase in frequency over time when measured sequentially in a large CLL cohort.

EXPERIMENTAL DESIGN

We sequentially sampled a large well-characterized CLL cohort at a mean of 4 years between samplings and measured acquired copy number aberrations (aCNA) and LOH using single-nucleotide polymorphism (SNP) 6.0 array profiling and the mutational state of TP53, NOTCH1, and SF3B1 using Sanger sequencing. The paired analysis included 156 patients, of whom 114 remained untreated and 42 received intercurrent therapies, predominantly potent chemoimmunotherapy, during the sampling interval.

RESULTS

We identify a strong effect of intercurrent therapies on the frequency of acquisition of aCNAs in CLL. Importantly, the spectrum of acquired genomic changes was largely similar in patients who did or did not receive intercurrent therapies; therefore, various genomic changes that become part of the dominant clones are often already present in CLL cell populations before therapy. Furthermore, we provide evidence that therapy of CLL with preexisting TP53 mutations results in outgrowth of genomically very complex clones, which dominate at relapse.

CONCLUSIONS

Using complementary technologies directed at the detection of genomic events that are present in substantial proportions of the clinically relevant CLL disease bulk, we capture aspects of genomic evolution in CLL over time, including increases in the frequency of genomic complexity, specific recurrent aCNAs, and TP53 mutations.

CLL cells respond to B-Cell receptor stimulation with a microRNA/mRNA signature associated with MYC activation and cell cycle progression

Chronic lymphocytic leukemia (CLL) is a disease with variable clinical outcome. Several prognostic factors such as the immunoglobulin heavy chain variable genes (IGHV) mutation status are linked to the B-cell receptor (BCR) complex, supporting a role for triggering the BCR in vivo in the pathogenesis. The miRNA profile upon stimulation and correlation with IGHV mutation status is however unknown. To evaluate the transcriptional response of peripheral blood CLL cells upon BCR stimulation in vitro, miRNA and mRNA expression was measured using hybridization arrays and qPCR. We found both IGHV mutated and unmutated CLL cells to respond with increased expression of MYC and other genes associated with BCR activation, and a phenotype of cell cycle progression. Genome-wide expression studies showed hsa-miR-132-3p/hsa-miR-212 miRNA cluster induction associated with a set of downregulated genes, enriched for genes modulated by BCR activation and amplified by Myc. We conclude that BCR triggering of CLL cells induces a transcriptional response of genes associated with BCR activation, enhanced cell cycle entry and progression and suggest that part of the transcriptional profiles linked to IGHV mutation status observed in isolated peripheral blood are not cell intrinsic but rather secondary to in vivo BCR stimulation.

Telomere length and expression of human telomerase reverse transcriptase splice variants in chronic lymphocytic leukemia

Telomerase activity and telomere length (TL) are prognostic markers in chronic lymphocytic leukemia (CLL). The rate-limiting component of telomerase is human telomerase reverse transcriptase (hTERT), for which multiple transcripts exist. Two splicing sites, α and β, have been described that generate deleted transcripts. Only the full-length (FL; α⁺β⁺) transcript translates into a functional protein. The aim of this work was to characterize hTERT splice variants in CLL in relation to disease activity, clinical stage, immunoglobulin heavy chain variable (IGHV) genes mutational status, and TL. Real-time polymerase chain reaction assays were validated for quantification of the hTERT transcripts with either α deletion (del-α; α⁻β⁺)), β deletion (del-β; α⁺β⁻) or both α and β deletions (del-αβ; α⁻β⁻). The splice variant expression pattern was studied in 97 patients with CLL, 6 healthy control subjects, and one CD34 cell sample. TL was assessed with real-time polymerase chain reaction in 71 of 97 samples. Thirty-two percent of the cases did not express any of the splice variants. Average FL expression was 5.5-fold higher in IGHV-unmutated (n = 35) compared with mutated (n = 59) patients (p < 0.0001). FL levels correlated directly with the percentage of IGHV homology (r = 0.34; p = 0.0007) and inversely with TL (r = -0.44; p = 0.0001). Overall, FL expression correlated significantly with that of the other splice variants. All transcripts were more frequently expressed in progressive compared with nonprogressive patients (p < 0.0001 for FL and del-α; p = 0.01 for del-β; and p = 0.006 for del-αβ). This study provides a detailed insight into the hTERT transcript pattern in CLL, highlighting the necessity of subgrouping patients according to IGHV mutation status when analyzing hTERT expression.

Lipoprotein lipase in chronic lymphocytic leukaemia - strong biomarker with lack of functional significance

In chronic lymphocytic leukaemia (CLL), lipoprotein lipase (LPL) mRNA overexpression is an established poor prognostic marker, its function, however, is poorly understood. Measuring extracellular LPL enzymatic activity and protein, we found no difference between levels in CLL patients and those of controls, both before and after heparin treatment in vivo and in vitro. Investigating LPL knock down effects, we determined five potential downstream targets, of which one gene, STXBP3, reportedly is involved in fatty acid metabolism. While possibly reflecting an epigenetic switch towards an incorrect transcriptional program, LPL overexpression by itself does not appear to significantly influence CLL cell survival.

Chromosomal abnormalities by conventional cytogenetics and interphase fluorescence in situ hybridization in chronic lymphocytic leukemia in Taiwan, an area with low incidence--clinical implication and comparison between the West and the East

Chronic lymphocytic leukemia (CLL) is much less prevalent in Taiwan than in the West, but we have recently addressed the distinctly increasing incidence of CLL in Taiwan. We sought to find out whether there is any difference in cytogenetic abnormalities (CA) of CLL between the West and the East. We analyze the CA, by conventional cytogenetics (CG) and fluorescence in situ hybridization (FISH), and their clinical significance in 83 Taiwanese CLL patients and compared the data to those of Western countries. Thirty-five patients (42.2 %) possessed CG-CA and 58 (69.9 %) FISH-CA. By either CG or FISH, deletion of 17p or 11q was associated with poorer overall survival (OS) (P<0.001 and P=0.008, respectively), whereas isolated 13q deletion was associated with better OS (P=0.050). Trisomy 3 by CG was found in five patients; all of them were in Binet A stage but had strikingly poor OS (P<0.001). This prognostic impact was independent from the other CA and Binet stages. We conclude that, though the disease incidence is much different, the CA of CLL in Taiwan are similar to those in the West. The combined CG and FISH analysis is able to predict the patients' prognosis. The clinical significance of trisomy 3 warrants further validation.

Circulating microenvironment of CLL: are nurse-like cells related to tumor-associated macrophages?

B-cell chronic lymphocytic leukemia (B-CLL) is one of the most common hematologic malignancies in Western countries. Accumulation of leukemic lymphocytes in peripheral blood, bone marrow and secondary lymphatic organs of CLL patients is due to decreased apoptosis rather than to increased proliferation. The former is driven by signals from a specific microenvironment, created by stromal cells of mesenchymal origin, follicular dendritic cells, T lymphocytes and others. Nurse-like cells (NLCs) were first described to differentiate from peripheral blood mononuclear cells of CLL patients in vitro, then they have been also found in proliferation centers of their lymphatic tissues. Like tumor-associated macrophages (TAMs) in solid tumors, nurse-like cells promote survival of CLL lymphocytes. NLC gene expression patterns suggest their similarity to TAMs and differ between patients depending on ZAP70 protein expression status. NLC number in vitro corresponds with CD14 expressing cell count and beta-2-microglobulin serum level, and positively correlates with leukemic lymphocyte viability. As NLCs strongly express genes for adhesion molecules and secrete chemokines of antiapoptotic activity, they should be considered as a target for anti-microenvironment therapy of this incurable disease.

HDAC isoenzyme expression is deregulated in chronic lymphocytic leukemia B-cells and has a complex prognostic significance

Histone deacetylases (HDACs) play a crucial role in chromatin structure and, consequently, gene expression. Their deregulation has been reported in various cancers. We performed a complete and comprehensive study of the expression of 18 HDACs (including Sirtuin; SIRT) by real-time PCR in a cohort of 200 chronic lymphocytic leukemia (CLL) patients with a median follow-up of 77 mo, and compared it with the results obtained from normal B cells. We also compared HDAC expression at diagnosis and after relapse. We observed significant deregulation (mostly upregulation) of HDACs in CLL. In terms of clinical significance, only HDAC6 was significantly correlated with treatment-free survival (TFS), whereas HDAC3 and SIRT2, 3 and 6 were correlated with overall survival (OS). A multivariate Cox regression stepwise analysis indicated that HDAC6, 7 and 10 and SIRT3 were TFS independent predictors. Interestingly, poor prognosis was associated with an overexpression of HDAC7 and 10 but an underexpression of HDAC6 and SIRT3. Therefore, these factors were combined in a TFS score: patients with a score of 0-1-2, 3 and 4 had a median TFS of 107, 57 and 26 mo, respectively (HR = 4.03, p < 0.0001). For OS, SIRT5 and 6 allowed stratification into 3 groups, with a median OS of > 360, 237 and 94 mo (HR = 6.38, p < 0.0001). However, we could not find statistical differences in HDAC expression after relapse. These results, validated by a 5-fold cross-validation, highlight the complex impact of HDAC expression in CLL clinical course.

IGHV gene mutational status and 17p deletion are independent molecular predictors in a comprehensive clinical-biological prognostic model for overall survival prediction in chronic lymphocytic leukemia

Background

Prognostic index for survival estimation by clinical-demographic variables were previously proposed in chronic lymphocytic leukemia (CLL) patients. Our objective was to test in a large retrospective cohort of CLL patients the prognostic power of biological and clinical-demographic variable in a comprehensive multivariate model. A new prognostic index was proposed.

Methods

Overall survival and time to treatment in 620 untreated CLL patients were analyzed retrospectively to evaluate the multivariate independence and predictive power of mutational status of immunoglobulin heavy chain variable gene segments (IGHV), high-risk chromosomal aberration such as 17p or 11q deletions, CD38 and ZAP-70 expression, age, gender, Binet stage, β2-microglobulin levels, absolute lymphocyte count and number of lymph node regions.

Results

IGHV mutational status and 17p deletion were the sole biological variables with independent prognostic relevance in a multivariate model for overall survival, which included easily measurable clinical parameters (Binet staging, β2-microglobulin levels) and demographics (age and gender). Analysis of time to treatment in Binet A patients below 70 years of age showed that IGHV was the most important predictor. A novel 6-variable clinical-biological prognostic index was developed and internally validated, which assigned 3 points for Binet C stage, 2 points/each for Binet B stage and for age > 65 years, 1 point/each for male gender, high β2-microglobulin levels, presence of an unmutated IGHV gene status or 17p deletion. Patients were classified at low-risk (score = 0-1; 21%), intermediate-risk (score 2-5; 63% of cases), high-risk (score 6-9; 16% of cases). Projected 5-year overall survival was 98%, 90% and 58% in low-, intermediate- and high-risk groups, respectively. A nomogram for individual patient survival estimation was also proposed.

Conclusions

Data indicate that IGHV mutational status and 17p deletion may be integrated with clinical-demographic variables in new prognostic tools to estimate overall survival.

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.

The cytokine midkine and its receptor RPTPζ regulate B cell survival in a pathway induced by CD74

Lasting B cell persistence depends on survival signals that are transduced by cell surface receptors. In this study, we describe a novel biological mechanism essential for survival and homeostasis of normal peripheral mature B cells and chronic lymphocytic leukemia cells, regulated by the heparin-binding cytokine, midkine (MK), and its proteoglycan receptor, the receptor-type tyrosine phosphatase ζ (RPTPζ). We demonstrate that MK initiates a signaling cascade leading to B cell survival by binding to RPTPζ. In mice lacking PTPRZ, the proportion and number of the mature B cell population are reduced. Our results emphasize a unique and critical function for MK signaling in the previously described MIF/CD74-induced survival pathway. Stimulation of CD74 with MIF leads to c-Met activation, resulting in elevation of MK expression in both normal mouse splenic B and chronic lymphocytic leukemia cells. Our results indicate that MK and RPTPζ are important regulators of the B cell repertoire. These findings could pave the way toward understanding the mechanisms shaping B cell survival and suggest novel therapeutic strategies based on the blockade of the MK/RPTPζ-dependent survival pathway.