Global Methylation Provides Independent Prognostic Information in Chronic Lymphocytic Leukemia and Is Associated with a Microrna Signature

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 3873-3873
Author(s):  
Alfons Navarro ◽  
Gerardo Ferrer ◽  
Marina Díaz-Beyá ◽  
Carmen Muñoz ◽  
Rut Tejero ◽  
...  
Keyword(s):  
Dna Methylation ◽  
High Risk ◽  
Chronic Lymphocytic Leukemia ◽  
Mirna Expression ◽  
Clinical Stage ◽  
Prognostic Significance ◽  
Surrogate Marker ◽  
Lymphocytic Leukemia ◽  
Prognostic Impact ◽  
Global Methylation

Abstract Abstract 3873 Introduction: Disruption of normal DNA methylation, including both gene specific hypermethylation and genome-wide hypomethylation, is found in most malignant tumors. Most epigenetic studies in chronic lymphocytic leukemia (CLL) have been focused in CpG islands and gene promoter regions, and have identified hypomethylated genes, such as BCL2 or TCL1, and hypermethylated genes, such as GRM7. However, the quantification of overall methylation measured as levels of 5-methylCytosine (5mC) has been poorly explored. As compared to their normal counterparts (CD19+ B cells), overall hypomethylation has been observed in CLL neoplastic cells. Importantly, the overall methylation varies among patients but its clinical significance has not been widely investigated. In addition, it is known that microRNA (miRNA) expression is altered in CLL, and that and epigenetic mechanisms, such as methylation, can affect miRNA expression. Aim: To investigate the prognostic impact of overall methylation in patients with CLL and to analyze the correlation of 5mC levels with miRNAs expression. Methods: We analyzed 73 CLL patients (median age, 69 [range, 34–86]; 43% males) diagnosed in our institution between 1992 and 2007. The median follow up was 10.5 years. The level of global methylation in total DNA was estimated after determination of percentage of 5mC using anti-5mC monoclonal antibodies (MethylFlash Methylated DNA Quantification Kit, Epigentek). The expression of 377 mature miRNAs was analyzed using TaqMan Array Human MicroRNA A Card v2.0 (Applied Biosystems). Statistical analysis was performed with SPSS version 15.0.1 and R software version 2.9.0. MaxStat package of R were used to determine the optimal cutoffs and Quantitative trail function in BRB array tools to correlate miRNA expression and methylation levels. Results: The analysis of methylation levels showed a wide distribution of methylation degree among patients (median: 3.02%, range: 0.58–6.14%). From the clinical standpoint, methylation levels were only correlated with Binet clinical stage, patients with C stage showing a higher degree of methylation (p=0.015). Using MaxStat, we identified two cutoffs which classified patients as having low, medium or high degree of methylation. Mean progression-free survival (PFS) was 8.4 years (95% CI: 6.4–10.4), 6.2 years (95% CI: 4.7–7.7) and 3.2 years (95% CI: 2.4–4.8) for patients with low, medium, and high methylation levels, respectively (p=0.013). In the multivariate analysis for PFS (including ZAP70, IGHV, Age≤65, cytogenetics and global methylation), high ZAP70 expression (HR: 3; 95%CI: 1.1–7.9; p=0.026) and high global methylation (HR: 5.4 95%CI: 1.7–17.1; p=0.004) were independent unfavorable prognostic factors, while a significant trend was observed for high-risk cytogenetics (17p-, 11q-, +12) (p=0.054). Interestingly, methylation levels retained its prognostic significance in subgroup analysis: clinical stage A (p=0.06) and B/C (p=0.009); mutated (p=0.008) and unmutated IGHV (p=0.028); low (p=0.028) and high ZAP70 (p=0.001); and low-risk (normal karyotype, 13q-)(p=0.008) and high-risk (17p-, 11q-, +12) cytogenetics (p=0.001). Finally, we identified a 4-miRNA signature associated with global methylation levels: miR-103 (Spearman correlation [SC]: −0.821;p=0.03), miR-132 (SC: 0.786;p=0.05), miR-494 (SC: −0.786; p=0.02), and miR-193a-5p (SC: 0.786; p=0.05). Interestingly, miR-103, miR-132 and miR-494 are located in subtelomeric regions, which are known to be more susceptible to overall methylation changes. Conclusions: In this study, the degree of global DNA methylation was an independent prognostic factor for PFS in patients with CLL. The analysis of overall methylation could be useful not only for the prognosis of patients with CLL but also in the monitoring of clinical trials in which hypomethylating agents (e.g., decitabine) are being investigated as CLL therapy. The correlation between overall methylation levels and certain miRNAs may be a surrogate marker of epigenetic lesions and deserves further investigation. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Prognostic significance of immunoglobulin phenotype in B cell chronic lymphocytic leukemia

Blood ◽  
1985 ◽  
Vol 65 (2) ◽  
pp. 340-344 ◽  
Author(s):  
L Baldini ◽  
R Mozzana ◽  
A Cortelezzi ◽  
A Neri ◽  
F Radaelli ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
B Cell ◽  
Clinical Stage ◽  
Prognostic Significance ◽  
Prognostic Index ◽  
Lymphocytic Leukemia ◽  
Leukemic Cells ◽  
Clinical Prognosis ◽  
Delta Type ◽  
Cell Chronic Lymphocytic Leukemia

Abstract Seventy-six consecutive untreated patients with B cell chronic lymphocytic leukemia (B-CLL) and classified according to Binet's staging system were studied at the clinical presentation. Several immunologic parameters (number of total and T circulating lymphocytes and their surface membrane immunoglobulin [Smlg] phenotypes and levels of serum Ig) were evaluated with the aim of identifying a biologic marker of prognostic relevance. In this series of persons, Binet staging confirmed its usefulness as a prognostic index (P less than .001). With regard to Smlg, they were mu-type in 41 cases (53.9%), mu- type plus delta-type in 29 cases (38.2%), alpha-type in one case, and not detectable in five cases. No correlations were found between clinical stage and immunoglobulin phenotype, although all but one patient in stage C showed mu-type Smlg alone. On analyzing the survival curves of our patients according to different Smlg phenotypes, we found that patients with only mu-type Smlg had a poorer prognosis (P less than .05) than those with mu-type plus delta-type; this difference was even more significant (P less than .01) in patients in stage A, whereas there were no statistical differences in those in stages B and C. Because the appearance of surface heavy chain of delta-type could be an expression of cell maturation, these results suggest that in B-CLL the presence of phenotypically more mature leukemic cells may correlate with better clinical prognosis, particularly in the early phase of the disease.

Abdominal Computed Tomography Predicts Progression in Patients With Rai Stage 0 Chronic Lymphocytic Leukemia

2007 ◽  
Vol 25 (12) ◽  
pp. 1576-1580 ◽  
Author(s):  
Ana Muntañola ◽  
Francesc Bosch ◽  
Pedro Arguis ◽  
Eduardo Arellano-Rodrigo ◽  
Carmen Ayuso ◽  
...  
Keyword(s):  
Computed Tomography ◽  
Chronic Lymphocytic Leukemia ◽  
Early Stage ◽  
Strong Predictor ◽  
Clinical Stage ◽  
Prognostic Significance ◽  
Clinical Information ◽  
Lymphocytic Leukemia ◽  
Abdominal Ct ◽  
Work Up

Purpose Whether computed tomography (CT) should be routinely included in the diagnostic work-up in patients with chronic lymphocytic leukemia (CLL) has not yet been determined. The aim of this study was to analyze the prognostic significance of abdominal CT in patients with CLL in Rai clinical stage 0. Patients and Methods Abdominal CT was performed at diagnosis in 140 patients consecutively diagnosed with CLL in Rai stage 0 disease. Results An abnormal abdominal CT was found in 38 patients (27%). Abnormal CT correlated with increased bone marrow infiltration (P = .024), high lymphocyte count (P = .001), increased ZAP-70 expression (P = .003), and short lymphocyte doubling time (LDT; P = .007). Patients with abnormal CT progressed more frequently and had a shorter time to progression than those with normal CT (median, 3.5 years v not reached, respectively; P < .001) and required earlier treatment intervention. In a multivariate analysis, only high ZAP-70 expression (relative risk = 3.60) and an abnormal abdominal CT (RR = 2.71) correlated with disease progression. Conclusion In this series, an abnormal abdominal CT was a strong predictor of progression in patients with early-stage CLL. The inclusion of CT scans in the initial work-up of patients with early clinical stage on clinical grounds can, therefore, provide relevant clinical information.

Additional Genetic High-Risk Features Such As 11q Deletion, 17p Deletion, and V3-21 Usage Characterize Discordance of ZAP-70 and VH Mutation Status in Chronic Lymphocytic Leukemia

2006 ◽  
Vol 24 (6) ◽  
pp. 969-975 ◽  
Author(s):  
Alexander Kröber ◽  
Johannes Bloehdorn ◽  
Sebastian Hafner ◽  
Andreas Bühler ◽  
Till Seiler ◽  
...  
Keyword(s):  
High Risk ◽  
Chronic Lymphocytic Leukemia ◽  
Variable Region ◽  
Multivariate Regression Analysis ◽  
Lymphocytic Leukemia ◽  
Prognostic Impact ◽  
Mutation Status ◽  
Characteristic Modes ◽  
Genomic Aberrations ◽  
Vh Gene

Purpose Immunoglobulin heavy chain variable-region (VH) gene mutation status and zeta-associated protein 70 (ZAP-70) expression are correlated in chronic lymphocytic leukemia (CLL), but their concordance is variable. The goal of this study was to elucidate additional factors potentially characterizing their discordance. Patients and Methods We evaluated ZAP-70 expression by flow cytometry, VH status by DNA sequencing, and genomic aberrations by fluorescence in situ hybridization in 148 CLL patients. The parameters were analyzed for their associations and their individual prognostic impact. Results ZAP-70 expression and VH mutation status were strongly associated in CLL without additional genetic high-risk-features as defined by the absence of 11q or 17p deletion and V3-21 usage (concordance 84%). In contrast, the proportion of discordant cases was significantly higher (39%), if such additional genetic high-risk features were present. Discordant cases with V3-21 usage were almost exclusively ZAP-70 positive and VH mutated (89%), whereas all but one of the discordant cases with high-risk aberrations were ZAP-70 negative and VH unmutated (92%). By multivariate regression analysis, two models were developed, which both include high-risk genomic aberrations and, alternatively, VH mutation status and V3-21 usage or ZAP-70 expression as independent outcome predictors. Conclusion There were characteristic modes of discordance between ZAP-70 and VH mutation status depending on the presence or absence of additional genetic high-risk features such as 11q and 17p deletion or V3-21 usage. Although the biologic background for these findings is yet to be determined, these data have biologic and clinical implications regarding ZAP-70 as a pathogenic factor and outcome predictor, respectively.

The Prognostic Significance of Positive Direct Antiglobulin Test in Chinese Patients with Chronic Lymphocytic Leukemia

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4183-4183
Author(s):  
Wei Xu ◽  
Jianyong Li ◽  
Xin Cao ◽  
DAN-Xia Zhu ◽  
Lin Yao ◽  
...  
Keyword(s):  
Prognostic Factors ◽  
Chronic Lymphocytic Leukemia ◽  
Prognostic Significance ◽  
Prognostic Indicator ◽  
Lymphocytic Leukemia ◽  
Direct Antiglobulin Test ◽  
Chinese Patients ◽  
Prognostic Impact ◽  
Antiglobulin Test ◽  
Positive Direct

Abstract Chronic lymphocytic leukemia (CLL) is the most common type of adult leukemias in the Western countries, however, infrequent in the Eastern. Autoimmune hemolytic anemia (AHA) is a complication in chronic lymphocytic leukemia (CLL). The direct antiglobulin test (DAT) may be positive at some time during the disease course in up to 35% of cases, but overt AHA occurs less frequently. The aim of the study was to explore the prognostic impact of positive DAT in Chinese patients with CLL and its correlation with other prognostic factors, including Binet stages, lymphocyte count in peripheral blood, lactate dehydrogenase (LDH), β2-microglobulin (β2-MG), IgVH mutation status, ZAP-70, CD38 and cytogenetic abnormalities. Out of the 80 Chinese patients with CLL, positive DAT was found in 21 (30.6%) cases. The incidence of positive was 12.5% in Binet A, 23.8% and 44.4% in Binet B and C, respectively. The incidence of positive DAT was significantly increased at Binet C, compared with Binet A (P=0.006), and the presence of higher LDH and β2-MG levels correlated strongly with positive DAT (P=0.006 and P=0.004, respectively). Patients with unmutated IgVH genes had higher incidence of positive DAT than did patients with IgVH mutations (P=0.042), and positive DAT was also associated with higher level of ZAP-70 and CD38 (P=0.004 and P&lt;0.001, respectively). We also analyzed positive DAT in different cytogenetic subgroups. Higher incidence of positive DAT was found in patients with unfavorable cytogenetic aberrations (deletion in 17p13 or 11q22) in contrast to lower level in good risk cytogenetics (deletion in 13q as the sole abnormality) (P = 0.002). Positive DAT was associated with poor outcome. Survival analysis showed that the patients with positive DAT had significantly shorter OS (mean, 106.3 months) (95% CI, 74.7 to 137.8 months) than the patients negative DAT (mean, 151.5 months) (95% CI, 122.3 to 180.6 months) (P=0.024). Patients treated with fludarabine were not likely to remain DAT positive and to change from negative to positive (P=0.209). In conclusion, DAT status provides a new prognostic indicator and correlates with other clinical or laboratory prognostic factors, and might be applied for the assessment of prognosis in patients with CLL.

Serum Tumor Markers in Non-Hodgkin's Lymphomas and Chronic Lymphocytic Leukemia

1993 ◽  
Vol 8 (1) ◽  
pp. 14-20 ◽  
Author(s):  
A.N. Pavlidis ◽  
J. Kalef-Ezra ◽  
L.C. Bourantas ◽  
A. Lambrou ◽  
A. Mavridis
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Tumor Markers ◽  
Clinical Stage ◽  
Prognostic Significance ◽  
Interleukin 2 ◽  
Serum Levels ◽  
Lymphocytic Leukemia ◽  
Mean Values ◽  
Hodgkin's Lymphomas ◽  
Normal Controls

The levels of soluble interleukin-2 receptors (sIL-2R), beta-2 microglobulin (β-2M), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were measured in the serum of 50 previously untreated patients with non-Hodgkin's lymphoma (NHL) and chronic lymphocytic leukemia (CLL) as well as in 25 age and sex-matched normal controls. Compared to normal controls, mean serum levels of sIL-2R and β-2M were significantly increased in both NHL and CLL (p < 0.001) while the increase in ESR and CRP was less marked (p < 0.01 and p < 0.05, respectively). Comparison of these tumor markers with histologic grading showed statistically significant differences only for CRP between low, intermediate and high-grade lymphomas (p < 0.001 and p < 0.05). More advanced stages exhibited higher mean values of all serum markers than early stages (p < 0.001 for sIL-2R, β-2M and ESR and p < 0.05 for CRP). An association with the presence of b-symptoms was observed only for sIL-2R (p < 0.05). In addition, sIL-2R as well as β-2M were able to predict time to progression in patients with diffuse large-cell lymphomas. We conclude that of the four tumor markers tested sIL-2R and β-2M more frequently showed increased serum levels and were associated with clinical stage and/or presence of b-symptoms. Both sIL-2R and β-2M were also found to have prognostic significance for survival.

ZAP-70 Expression in Chronic Lymphocytic Leukemia: Correlation with Clinical and Biological Features.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 1915-1915 ◽  
Author(s):  
Ilaria Del Giudice ◽  
Nnenna Osuji ◽  
Estella Matutes ◽  
Alison Morilla ◽  
Ricardo Morilla ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Prognostic Value ◽  
Clinical Stage ◽  
Univariate Analysis ◽  
Surrogate Marker ◽  
Lymphocytic Leukemia ◽  
Over Expression ◽  
Biological Features ◽  
Free Interval ◽  
Mutational Status

Abstract One of the most intriguing features of chronic lymphocytic leukemia (CLL) is its clinical heterogeneity. The mutational status of immunoglobulin heavy chain variable region (IgVH) genes is one of the most powerful predictors of overall survival (OS) and progression-free survival (PFS). The expression of the tyrosine kinase ZAP-70 in CLL cells has been proposed as a surrogate marker for the mutational status of IgVH genes. Recent reports suggest that ZAP-70 over-expression is an independent prognostic factor for shorter OS and PFS. There is little information about correlation between ZAP-70 expression and other clinical and biological features in CLL. The aims of this study are 1) to evaluate prospectively ZAP-70 expression in a series of CLL patients; 2) to correlate this with clinical stage, lymphocyte morphology, CD38 expression and chromosomal abnormalities detected by FISH and 3) to analyze the independent prognostic value of ZAP-70 in predicting time to first treatment (treatment free interval, TFI). ZAP-70 expression was analyzed using four-colour flow cytometry (as described by Crespo et al, NEJM2003; 348:1764–75). 201 previously untreated CLL patients were evaluated at diagnosis (32%) or during the disease course. Amongst them, 143 patients were entered in the LRF CLL4 trial. Clinical stage at the time of the study was A in 92 patients (A progressive in 46), B in 63 and C in 46. 28% were ZAP-70 positive (+) (cut-off ≥ 20% of CD5/CD19+ cells). ZAP-70 positivity was associated with prevalence of stage B/C at diagnosis (p=0.004), CLL with >10% prolymphocytes (CLL/PL) or atypical morphology (p<0.001), CD38 positivity (regardless of the cut-off point) (p<0.001), trisomy12 (p=0.001), del(6)(q21) (p=0.05) or no detectable abnormalities (0.002). ZAP-70 negative (−) cases presented more often with del(13)(q14) (p<0.001). There were no significant differences in the frequency of del(11)(q23) or delp53 between ZAP-70(+) and ZAP-70(−) cases. Median time from diagnosis to first treatment (treatment free interval, TFI) was 17.7 months for ZAP-70(+) and 44.6 months for ZAP-70(−) cases (p<0.001). The presence of the following parameters was associated with short TFI in univariate analysis: male sex (p=0.02), atypical morphology (p=0.02), clinical stage B/C (p<0.001), ZAP-70(+) (p<0.001), CD38+ (p<0.001), absence of del(13)(q14) (p<0.001), presence of delp53 (p=0.05). Multivariate analysis is being performed. In conclusion, we document a significant correlation between ZAP-70 over-expression in CLL and other adverse prognostic factors (such as CD38 and advanced stage), provide new data concerning its association with cytogenetic abnormalities detected by FISH and demonstrate the prognostic value of ZAP-70 expression.

Occurrence of Chromosomal Translocations as Independent Prognostic Factor in Chronic Lymphocytic Leukemia.

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 2084-2084
Author(s):  
Christine Mayr ◽  
Cathrine Schulz ◽  
Stephan Stilgenbauer ◽  
Alexander Kröber ◽  
Hartmut Döhner ◽  
...  
Keyword(s):  
Risk Factor ◽  
Prognostic Factors ◽  
High Risk ◽  
Prognostic Factor ◽  
Chronic Lymphocytic Leukemia ◽  
Prognostic Significance ◽  
Lymphocytic Leukemia ◽  
Chromosomal Translocations ◽  
Study Cohort ◽  
Binet Stage

Abstract Background: The course of chronic lymphocytic leukemia (CLL) is highly variable. Therefore, there is a need for prognostic factors that are readily performed and have a high predictive power. Methods: The occurrence of translocations, a recently identified prognostic factor in CLL (Blood2006;107:742–751), was studied in 148 previously untreated, mostly early-stage patients and compared with respect to treatment-free survival (TFS) to several prognostic factors (Binet stage, mutational status of immunoglobulin genes, CD38, thymidine kinase serum concentration and cytogenetic aberrations detected by interphase FISH). To investigate chromosomal translocations, we applied a new method, CpG oligodeoxynucleotide stimulation that allows efficient preparation of metaphase spreads from CLL cells. Results: The occurrence of translocations classified the majority of patients with poor prognosis. If translocations were investigated in addition to the currently used prognostic factors they identified those patients who were classified to be in a low-risk group based on traditionally used criteria, who had in fact a high risk for progression. Vice versa, patients in the high-risk groups for progression who did not have translocations had a long TFS. There was a substantial overlap of patients who had translocations and additional risk factors. But when we omitted patients who had translocations in addition to a given risk factor, we found that the respective risk factor lost its prognostic significance for the remaining patients. The two factors that retained their prognostic power in these patients were translocations and the Binet stage. This could suggest that the prognostic significance of the currently used factors derives from their frequent co-occurrence with translocations. Finally, multivariate analyses demonstrated that Binet stage (p=0.02) and translocations (p=0.0005) are the factors with the highest impact on TFS in our study cohort. Conclusion: We present a method for efficient preparation of metaphase spreads in CLL cells in order to investigate chromosomal translocations. The occurrence of translocations is an independent prognostic marker in CLL. Finally, translocations occur not as a late event in the course of the disease and may define a new biological subgroup in this disease entity.

Angiopoietin-2 mRNA Expression Is Elevated in Chronic Lymphocytic Leukemia Patients with Poor Prognostic Features

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 4182-4182
Author(s):  
Filip Vrbacky ◽  
Lukas Smolej ◽  
Vladimira Vroblova ◽  
Sona Pekova ◽  
Monika Hrudkova ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Mononuclear Cells ◽  
Statistical Significance ◽  
Clinical Stage ◽  
Prognostic Significance ◽  
Progression Free Survival ◽  
Lymphocytic Leukemia ◽  
Mrna Levels ◽  
Prognostic Features ◽  
Angiopoietin 2

Abstract Several studies have demonstrated potential prognostic importance of angiogenesis in chronic lymphocytic leukemia (CLL). Elevated expression of angiogenic activator angiopoietin-2 (Ang-2) was recently reported in CLL but data regarding prognostic significance of Ang-2 in CLL is limited. Therefore, we evaluated potential relationship between Ang-2 expression and other prognostic factors in patients with CLL. Ang-2 mRNA was quantified by real-time quantitative PCR in purified mononuclear cells of 33 untreated CLL patients. Ang-2 transcript levels were further analyzed with regard to clinical stage, disease course, IgVH mutation status, CD38 and ZAP-70 expression. Elevated Ang-2 mRNA was detected in 12 cases; twenty-one patients had very low or undetectable levels of Ang-2 transcript. High Ang-2 mRNA levels were significantly associated with unmutated IgVH genes (p=0.010) and high CD38 expression (p=0.011) but not with ZAP-70 expression (p=0.784), Rai stage (p=0.305) or stable vs. progressive clinical course (p=0.443). Interestingly, there was a trend towards shorter progression-free survival in patients with high Ang-2 expression, but it did not reach statistical significance (median 15 months vs. not reached; p=0.090). In conclusion, our data show that Ang-2 mRNA is differentially expressed in patients with CLL and its increased expression appears to be associated with poor prognostic features.

Genome-Wide Methylation Arrays Reveal Distinct Methylation Profiles in Prognostic Subsets of Chronic Lymphocytic Leukemia.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 364-364
Author(s):  
Nicola Cahill ◽  
Meena Kanduri ◽  
Hanna Göransson ◽  
Anders Isaksson ◽  
Camilla Enström ◽  
...  
Keyword(s):  
Dna Methylation ◽  
Chronic Lymphocytic Leukemia ◽  
Tumor Suppressor ◽  
Methylation Status ◽  
Lymphocytic Leukemia ◽  
Epigenetic Mechanism ◽  
Absolute Difference ◽  
Global Methylation ◽  
Genome Wide ◽  
Differentially Methylated Genes

Abstract Abstract 364 Introduction: Aberrant DNA methylation has been shown to play a strong role in tumorogenesis, where genome-wide hypomethylation and regional hypermethylation of tumor suppressor gene (TGS) promoters are characteristic hallmarks of many cancers. In chronic lymphocytic leukemia (CLL), the epigenetic mechanism of gene regulation has thus far received limited attention, although promoter methylation and transcriptional silencing has been shown for certain individual genes, for example, DAPK1, ZAP70 and PEG10. To date, only the ‘Restriction Landmark Genomic Scanning' technique has been performed to assess the genome-wide methylation status in CLL. However, this technique spans only 3000 CpG islands and does not give a full coverage of the genome. Patients and methods: Here, we analyzed the global methylation profiles in CLL by applying high-resolution genome-wide methylation arrays from Illumina that cover 28,000 CpG sites, spanning 14,000 genes. Specifically, 23 CLL samples belonging to the immunoglobulin heavy-chain variable (IGHV) mutated (favorable prognostic) and IGHV unmutated/IGHV3-21 (poor-prognostic) subsets were analysed. The raw data was processed using the BeadStudio software followed by bioinformatic analysis where the arcsin transformed data was used in a moderated t-test to find differentially methylated genes. Only genes with a large absolute difference between the groups were included for further analysis. Methylation-specific PCR (MSP-PCR) and realtime-PCR (RQ-PCR) were performed on a selection of genes to confirm the array data. Additionally, bi-sulfite sequencing was employed on selected genes to confirm the degree of methylation. Moreover, CLL samples were treated with the DNA methyl transferase inhibitor 5-aza-2'-deoxycytidine combined with and without the histone deacetylase inhibitor (HDAC) trichostatin A to induce re-expression of selected methylated genes Results: Overall, we observed significant differences in methylation patterns between the CLL subgroups. Specifically, we identified TSGs that were preferentially methylated in the IGHV unmutated (7 genes, e.g. VHL, ABI3) and IGHV3-21(1 gene, SLC22A18) subgroups. We also identified 10 unmethylated and hence potentially expressed genes shown to be involved in activation of proliferative pathways such as the NFkB pathway (e.g. ADORA3), and the MAP/ERK kinase pathway (e.g. FABP7) in the IGHV unmutated and IGHV3-21 subgroups. In contrast, these latter genes were silenced by methylation in IGHV mutated patients. The methylation status was verified for 4 genes (BCL10, PRF1, ADORA3 and IGSF4) by MSP-PCR and the expression status of 7 genes (BCL10, PRF1, ADORA3, IGSF4, NGFR, ABI3 and VHL) was confirmed using RQ-PCR. Furthermore, bi-sulfite sequencing confirmed the degree of methylation for 2 methylated TSGs (VHL and ABI3) in unmutated CLL samples. Finally, the significance of DNA methylation in regulating gene promoters was shown by re-inducing 3 methylated TSGs ( VHL, ABI3 and IGSF4) in IGHV unmutated samples using the methyl-inhibitor 5-aza-2'-deoxycytidine. Conclusion: Taken together, our data for the first time reveals differences in global methylation profiles between prognostic subsets of CLL, which may unfold important epigenetic silencing mechanisms involved in CLL pathogenesis. Specific inhibition of expression of unmethylated genes involved in facilitating tumorogenesis and re-expression of methylated tumor suppressor genes within the poor-prognostic CLL subgroups may represent potential new drug therapy targets. Disclosures: No relevant conflicts of interest to declare.

Chronic Lymphocytic Leukemia Associated with Autoimmune Hemolytic Anemia Is Characterized by a Distinctive miRNA Signature,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3897-3897
Author(s):  
Gerardo Ferrer ◽  
Alfons Navarro ◽  
Kate E Hodgson ◽  
Dolors Colomer ◽  
Marta Aymerich ◽  
...  
Keyword(s):  
Chronic Lymphocytic Leukemia ◽  
Hemolytic Anemia ◽  
Mirna Expression ◽  
Autoimmune Hemolytic Anemia ◽  
Conflicts Of Interest ◽  
Detection System ◽  
Clinical Stage ◽  
Lymphocytic Leukemia ◽  
Unsupervised Hierarchical Cluster ◽  
Mirna Signature

Abstract Abstract 3897 Chronic lymphocytic leukemia (CLL) is frequently associated with autoimmune hemolytic anemia (AIHA). However, the mechanisms governing the association between CLL and AIHA are poorly understood. MicroRNAs (miRNAs) are small 18–22 nucleotide long RNA molecules that regulate gene expression and play a key role in several biological processes. Importantly, deregulated miRNA expression has been implicated both in CLL and autoimmunity. This led us to speculate that patients with CLL who develop AIHA might have a different miRNA expression pattern as compared to those in whom this complication is not observed. We report here the first results of this study. We have evaluated the miRNA expression in purified CLL cells (CD19+, CD5+) from 14 patients who developed AIHA over the course of their disease and 19 sex-, age-, and clinical stage-matched controls who, after a comparable follow up time, did not develop this complication. The expression of 377 mature miRNAs was analyzed using TaqMan Human MicroRNA Arrays A v2.0 (Applied Biosystems) in an ABI 7900 HT sequence detection system. miRNA expression data was analyzed by the 2–ΔΔCt method, using RNU48 as endogenous control. Statistical analyses were performed with TiGR MultiExperiment Viewer, BRB-ArrayTools and R software. The unsupervised hierarchical cluster analysis identified two groups (CLL AIHA+ and CLL AIHA-). The supervised analysis revealed 7 miRNAs that were down-regulated in CLL AIHA+ patients compared to CLL AIHA- patients: miR-19a, miR-20a, miR-29c, miR-146b-5p, miR-324-3p, miR-340, miR-660. Interestingly, miR-146, which has previously been related to autoimmunity, regulates IL-1 receptor-associated kinase 1 and TNF receptor-associated factor 6, two key adapter molecules downstream of Toll-like and cytokine receptors. The prediction analysis of microarrays (PAM) was used to determine a set of miRNAs able to classify the samples into CLL AIHA+ and CLL AIHA-. We obtained a 122-miRNA model that classified CLL AIHA+ patients with a sensitivity of 69.4% and specificity of 68.4%. This model correctly classified 67% of the analyzed samples. In summary, CLL AIHA+ samples were characterized by a distinctive signature of 7 down-regulated miRNAs, one of which (miR-146) has previously been related to autoimmunity. Moreover, we identified 122 miRNAs that are able to predict AIHA in CLL patients. This is the first study establishing a relationship with CLL associated with AIHA and a distinctive miRNA signature, which should be useful for further studies aimed at unfolding the biologic complexity of AIHA in CLL. Disclosures: No relevant conflicts of interest to declare.

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