1 4432 96 MOLECULAR CHARACTERIZATION OF RICHTER SYNDROME IDENTIFIES DE NOVO DIFFUSE LARGE B-CELL LYMPHOMAS WITH POOR PROGNOSIS. RICHTER SYNDROME (RS) IS THE TRANSFORMATION OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) INTO AGGRESSIVE LYMPHOMA, MOST COMMONLY DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL). WE CHARACTERIZE 58 PRIMARY HUMAN RS SAMPLES BY GENOME-WIDE DNA METHYLATION AND WHOLE-TRANSCRIPTOME PROFILING. OUR COMPREHENSIVE APPROACH DETERMINES RS DNA METHYLATION PROFILE AND UNRAVELS A CLL EPIGENETIC IMPRINT, ALLOWING CLL-RS CLONAL RELATIONSHIP ASSESSMENT WITHOUT THE NEED OF THE INITIAL CLL TUMOR DNA. DNA METHYLATION- AND TRANSCRIPTOMIC-BASED CLASSIFIERS WERE DEVELOPED, AND TESTING ON LANDMARK DLBCL DATASETS IDENTIFIES A POOR-PROGNOSIS, ACTIVATED B-CELL-LIKE DLBCL SUBSET IN 111/1772 SAMPLES. THE CLASSIFICATION ROBUSTLY IDENTIFIES PHENOTYPES VERY SIMILAR TO RS WITH A SPECIFIC GENOMIC PROFILE, ACCOUNTING FOR 4.3-8.3% OF DE NOVO DLBCLS. IN THIS WORK, RS MULTI-OMICS CHARACTERIZATION DETERMINES ONCOGENIC MECHANISMS, ESTABLISHES A SURROGATE MARKER FOR CLL-RS CLONAL RELATIONSHIP, AND PROVIDES A CLINICALLY RELEVANT CLASSIFIER FOR A SUBSET OF PRIMARY "RS-TYPE DLBCL" WITH UNFAVORABLE PROGNOSIS. 2023 2 3024 34 GENETICS AND PATHOGENESIS OF DIFFUSE LARGE B-CELL LYMPHOMA. BACKGROUND: DIFFUSE LARGE B-CELL LYMPHOMAS (DLBCLS) ARE PHENOTYPICALLY AND GENETICALLY HETEROGENEOUS. GENE-EXPRESSION PROFILING HAS IDENTIFIED SUBGROUPS OF DLBCL (ACTIVATED B-CELL-LIKE [ABC], GERMINAL-CENTER B-CELL-LIKE [GCB], AND UNCLASSIFIED) ACCORDING TO CELL OF ORIGIN THAT ARE ASSOCIATED WITH A DIFFERENTIAL RESPONSE TO CHEMOTHERAPY AND TARGETED AGENTS. WE SOUGHT TO EXTEND THESE FINDINGS BY IDENTIFYING GENETIC SUBTYPES OF DLBCL BASED ON SHARED GENOMIC ABNORMALITIES AND TO UNCOVER THERAPEUTIC VULNERABILITIES BASED ON TUMOR GENETICS. METHODS: WE STUDIED 574 DLBCL BIOPSY SAMPLES USING EXOME AND TRANSCRIPTOME SEQUENCING, ARRAY-BASED DNA COPY-NUMBER ANALYSIS, AND TARGETED AMPLICON RESEQUENCING OF 372 GENES TO IDENTIFY GENES WITH RECURRENT ABERRATIONS. WE DEVELOPED AND IMPLEMENTED AN ALGORITHM TO DISCOVER GENETIC SUBTYPES BASED ON THE CO-OCCURRENCE OF GENETIC ALTERATIONS. RESULTS: WE IDENTIFIED FOUR PROMINENT GENETIC SUBTYPES IN DLBCL, TERMED MCD (BASED ON THE CO-OCCURRENCE OF MYD88(L265P) AND CD79B MUTATIONS), BN2 (BASED ON BCL6 FUSIONS AND NOTCH2 MUTATIONS), N1 (BASED ON NOTCH1 MUTATIONS), AND EZB (BASED ON EZH2 MUTATIONS AND BCL2 TRANSLOCATIONS). GENETIC ABERRATIONS IN MULTIPLE GENES DISTINGUISHED EACH GENETIC SUBTYPE FROM OTHER DLBCLS. THESE SUBTYPES DIFFERED PHENOTYPICALLY, AS JUDGED BY DIFFERENCES IN GENE-EXPRESSION SIGNATURES AND RESPONSES TO IMMUNOCHEMOTHERAPY, WITH FAVORABLE SURVIVAL IN THE BN2 AND EZB SUBTYPES AND INFERIOR OUTCOMES IN THE MCD AND N1 SUBTYPES. ANALYSIS OF GENETIC PATHWAYS SUGGESTED THAT MCD AND BN2 DLBCLS RELY ON "CHRONIC ACTIVE" B-CELL RECEPTOR SIGNALING THAT IS AMENABLE TO THERAPEUTIC INHIBITION. CONCLUSIONS: WE UNCOVERED GENETIC SUBTYPES OF DLBCL WITH DISTINCT GENOTYPIC, EPIGENETIC, AND CLINICAL CHARACTERISTICS, PROVIDING A POTENTIAL NOSOLOGY FOR PRECISION-MEDICINE STRATEGIES IN DLBCL. (FUNDED BY THE INTRAMURAL RESEARCH PROGRAM OF THE NATIONAL INSTITUTES OF HEALTH AND OTHERS.). 2018 3 5512 33 RICHTER SYNDROME IN CHRONIC LYMPHOCYTIC LEUKEMIA: UPDATES ON BIOLOGY, CLINICAL FEATURES AND THERAPY. RICHTER SYNDROME (RS) OR RICHTER TRANSFORMATION IS THE DEVELOPMENT OF SECONDARY AGGRESSIVE LYMPHOMA IN THE SETTING OF UNDERLYING CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA (CLL/SLL). MOST FREQUENTLY CLL TRANSFORMS INTO DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL) (90%) AND RARELY (10%) INTO HODGKIN LYMPHOMA, TERMED HODGKIN VARIANT OF RICHTER SYNDROME (HVRS). RS IS GENERALLY CHARACTERIZED BY AN AGGRESSIVE CLINICAL COURSE AND POOR PROGNOSIS. IN RECENT YEARS, MAJOR ADVANCES HAVE BEEN MADE IN UNDERSTANDING GENETIC EVENTS WHICH RELATE TO THE PROGRESSION OF CLL OR TRANSFORMATION INTO RS. BETTER UNDERSTANDING OF THE MOLECULAR PATHWAYS HAS REVEALED THAT RS IS NOT A SINGLE HOMOGENEOUS ENTITY. THE MAJORITY OF CASES ARE CLONALLY RELATED TO THE ORIGINAL CLL CLONE, WHILE A MINORITY DEVELOP FROM AN UNRELATED CLONE. THIS REVIEW SUMMARIZES NEW DATA RELATING TO THE MOLECULAR BIOLOGY AND THE GENETIC/EPIGENETIC CHANGES OCCURRING DURING RICHTER TRANSFORMATION, AND ALSO CONSIDERS THE CLINICAL FEATURES AND THERAPY FOR BOTH DLBCL-RS AND HODGKIN VARIANT-RS. 2015 4 1693 35 DUSP4 DEFICIENCY CAUSED BY PROMOTER HYPERMETHYLATION DRIVES JNK SIGNALING AND TUMOR CELL SURVIVAL IN DIFFUSE LARGE B CELL LYMPHOMA. THE EPIGENETIC DYSREGULATION OF TUMOR SUPPRESSOR GENES IS AN IMPORTANT DRIVER OF HUMAN CARCINOGENESIS. WE HAVE COMBINED GENOME-WIDE DNA METHYLATION ANALYSES AND GENE EXPRESSION PROFILING AFTER PHARMACOLOGICAL DNA DEMETHYLATION WITH FUNCTIONAL SCREENING TO IDENTIFY NOVEL TUMOR SUPPRESSORS IN DIFFUSE LARGE B CELL LYMPHOMA (DLBCL). WE FIND THAT A CPG ISLAND IN THE PROMOTER OF THE DUAL-SPECIFICITY PHOSPHATASE DUSP4 IS ABERRANTLY METHYLATED IN NODAL AND EXTRANODAL DLBCL, IRRESPECTIVE OF ABC OR GCB SUBTYPE, RESULTING IN LOSS OF DUSP4 EXPRESSION IN 75% OF >200 EXAMINED CASES. THE DUSP4 GENOMIC LOCUS IS FURTHER DELETED IN UP TO 13% OF AGGRESSIVE B CELL LYMPHOMAS, AND THE LACK OF DUSP4 IS A NEGATIVE PROGNOSTIC FACTOR IN THREE INDEPENDENT COHORTS OF DLBCL PATIENTS. ECTOPIC EXPRESSION OF WILD-TYPE DUSP4, BUT NOT OF A PHOSPHATASE-DEFICIENT MUTANT, DEPHOSPHORYLATES C-JUN N-TERMINAL KINASE (JNK) AND INDUCES APOPTOSIS IN DLBCL CELLS. PHARMACOLOGICAL OR DOMINANT-NEGATIVE JNK INHIBITION RESTRICTS DLBCL SURVIVAL IN VITRO AND IN VIVO AND SYNERGIZES STRONGLY WITH THE BRUTON'S TYROSINE KINASE INHIBITOR IBRUTINIB. OUR RESULTS INDICATE THAT DLBCL CELLS DEPEND ON JNK SIGNALING FOR SURVIVAL. THIS FINDING PROVIDES A MECHANISTIC BASIS FOR THE CLINICAL DEVELOPMENT OF JNK INHIBITORS IN DLBCL, IDEALLY IN SYNTHETIC LETHAL COMBINATIONS WITH INHIBITORS OF CHRONIC ACTIVE B CELL RECEPTOR SIGNALING. 2015 5 185 28 ACCUMULATION OF ABERRANT CPG HYPERMETHYLATION BY HELICOBACTER PYLORI INFECTION PROMOTES DEVELOPMENT AND PROGRESSION OF GASTRIC MALT LYMPHOMA. ABERRANT DNA HYPERMETHYLATION IS AN IMPORTANT MECHANISM FOR THE INACTIVATION OF TUMOR-RELATED GENES IN HUMAN TUMORS. GASTRIC MUCOSA-ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMAS ARISE FROM HELICOBACTER PYLORI-ASSOCIATED CHRONIC GASTRITIS; MOST PATIENTS ARE H. PYLORI-POSITIVE AND ERADICATION THERAPY IS HIGHLY EFFECTIVE. IN THE PRESENT STUDY, WE USED METHYLATION-SPECIFIC PCR TO ANALYZE THE DNA METHYLATION STATUS OF 11 TUMOR-RELATED GENES (KIP2, P16, HMLH-1, P15, P73, MGMT, DAPK, MINT1, MINT2, MINT31 AND HCAD) IN 21 SPECIMENS OF MALT LYMPHOMA, 5 SPECIMENS OF MALT LYMPHOMA WITH LARGE CELL COMPONENT (HIGH-GRADE MALT LYMPHOMA), 15 SPECIMENS OF DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL), 8 SPECIMENS OF COMPLETE REMISSION OF MALT LYMPHOMA AFTER ERADICATION THERAPY, 5 SPECIMENS WITH NO EVIDENCE OF MALIGNANCY AND PBMCS FROM 10 HEALTHY DONORS. THE AVERAGE NUMBER OF METHYLATED GENES WAS SIGNIFICANTLY GREATER IN GASTRIC LYMPHOMAS AS COMPARED TO NORMAL CONTROLS (P<0.001). THE CPG ISLAND METHYLATOR PHENOTYPE (CIMP) WAS OBSERVED IN 93.3% (14/15) OF DLBCLS, 100% (5/5) OF HIGH-GRADE MALT LYMPHOMAS AND 61.9% (13/21) OF MALT LYMPHOMAS; IN CONTRAST, CIMP WAS NOT FOUND IN THE CONTROL GROUP (0%). THE AVERAGE NUMBER OF METHYLATED GENES AND THE CIMP INCIDENCE SIGNIFICANTLY INCREASED WITH H. PYLORI INFECTION. FURTHERMORE, ABERRANT CPG METHYLATION OF SPECIFIC GENES, SUCH AS P16, MGMT AND MINT31, WAS CONSISTENTLY ASSOCIATED WITH H. PYLORI INFECTION. THESE FINDINGS STRONGLY SUGGEST THAT H. PYLORI INFECTION CAUSES THE ABERRANT DNA HYPERMETHYLATION OF SPECIFIC GENES AND INDUCES CIMP, WHICH IS AN IMPORTANT EPIGENETIC MECHANISM FOR THE DEVELOPMENT AND PROGRESSION OF GASTRIC MALT LYMPHOMA; ADDITIONALLY, OUR FINDINGS PROVIDE NEW EPIGENETIC MARKERS. 2009 6 1467 30 DISTINCT CLINICAL AND GENETIC FEATURES OF HEPATITIS B VIRUS-ASSOCIATED FOLLICULAR LYMPHOMA IN CHINESE PATIENTS. HEPATITIS B VIRUS (HBV) INFECTION HAS BEEN ASSOCIATED WITH AN INCREASED RISK FOR B-CELL LYMPHOMAS. WE PREVIOUSLY SHOWED THAT 20% OF DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL) PATIENTS FROM CHINA, AN ENDEMIC AREA OF HBV INFECTION, HAVE CHRONIC HBV INFECTION (SURFACE ANTIGEN-POSITIVE, HBSAG+) AND ARE CHARACTERIZED BY DISTINCT CLINICAL AND GENETIC FEATURES. HERE, WE SHOWED THAT 24% OF FOLLICULAR LYMPHOMA (FL) CHINESE PATIENTS ARE HBSAG+. COMPARED WITH THE HBSAG- FL PATIENTS, HBSAG+ PATIENTS ARE YOUNGER, HAVE A HIGHER HISTOLOGICAL GRADE AT DIAGNOSIS, AND HAVE A HIGHER INCIDENCE OF DISEASE PROGRESSION WITHIN 24 MONTHS. MOREOVER, BY SEQUENCING THE GENOMES OF 109 FL TUMORS, WE OBSERVED ENHANCED MUTAGENESIS AND DISTINCT GENETIC PROFILE IN HBSAG+ FLS, WITH A UNIQUE SET OF PREFERENTIALLY MUTATED GENES (TNFAIP3, FAS, HIST1H1C, KLF2, TP53, PIM1, TMSB4X, DUSP2, TAGAP, LYN, AND SETD2) BUT LACK OF THE HALLMARK OF HBSAG- FLS (IE, IGH/BCL2 TRANSLOCATIONS AND CREBBP MUTATIONS). TRANSCRIPTOMIC ANALYSES FURTHER SHOWED THAT HBSAG+ FLS DISPLAYED GENE-EXPRESSION SIGNATURES RESEMBLING THE ACTIVATED B-CELL-LIKE SUBTYPE OF DIFFUSE LARGE B-CELL LYMPHOMA, INVOLVING IRF4-TARGETED GENES AND NF-KAPPAB/MYD88 SIGNALING PATHWAYS. FINALLY, WE IDENTIFIED AN INCREASED INFILTRATION OF CD8+ MEMORY T CELLS, CD4+ TH1 CELLS, AND M1 MACROPHAGES AND HIGHER T-CELL EXHAUSTION GENE SIGNATURE IN HBSAG+ FL SAMPLES. TAKEN TOGETHER, WE PRESENT NEW GENETIC/EPIGENETIC EVIDENCE THAT LINKS CHRONIC HBV INFECTION TO B-CELL LYMPHOMAGENESIS, AND HBV-ASSOCIATED FL IS LIKELY TO HAVE A DISTINCT CELL-OF-ORIGIN AND REPRESENT AS A SEPARATE SUBTYPE OF FL. TARGETABLE GENETIC/EPIGENETIC ALTERATIONS IDENTIFIED IN TUMORS AND THEIR ASSOCIATED TUMOR MICROENVIRONMENT MAY PROVIDE POTENTIAL NOVEL THERAPEUTIC APPROACHES FOR THIS SUBGROUP OF PATIENTS. 2022 7 5462 25 RESEARCH PROGRESS ON EPIGENETICS OF SMALL B-CELL LYMPHOMA. SMALL B-CELL LYMPHOMA IS THE CLASSIFICATION OF B-CELL CHRONIC LYMPHOPROLIFERATIVE DISORDERS THAT INCLUDE CHRONIC LYMPHOCYTIC LEUKAEMIA/SMALL LYMPHOCYTIC LYMPHOMA, FOLLICULAR LYMPHOMA, MANTLE CELL LYMPHOMA, MARGINAL ZONE LYMPHOMA, LYMPHOPLASMACYTIC LYMPHOMA/WALDENSTROM MACROGLOBULINEMIA. THE CLINICAL PRESENTATION IS SOMEWHAT HETEROGENEOUS, AND ITS OCCURRENCE AND DEVELOPMENT MECHANISMS ARE NOT YET PRECISE AND MAY INVOLVE EPIGENETIC CHANGES. EPIGENETIC ALTERATIONS MAINLY INCLUDE DNA METHYLATION, HISTONE MODIFICATION, AND NON-CODING RNA, WHICH ARE ESSENTIAL FOR GENETIC DETECTION, EARLY DIAGNOSIS, AND ASSESSMENT OF TREATMENT RESISTANCE IN SMALL B-CELL LYMPHOMA. AS CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA HAS ALREADY BEEN REPORTED IN THE LITERATURE, THIS ARTICLE FOCUSES ON SMALL B-CELL LYMPHOMAS SUCH AS FOLLICULAR LYMPHOMA, MANTLE CELL LYMPHOMA, MARGINAL ZONE LYMPHOMA, AND WALDENSTROM MACROGLOBULINEMIA. IT DISCUSSES RECENT DEVELOPMENTS IN EPIGENETIC RESEARCH TO DIAGNOSE AND TREAT THIS GROUP OF LYMPHOMAS. THIS REVIEW PROVIDES NEW IDEAS FOR THE TREATMENT AND PROGNOSIS ASSESSMENT OF SMALL B-CELL LYMPHOMA BY EXPLORING THE CONNECTION BETWEEN SMALL B-CELL LYMPHOMA AND EPIGENETICS. 2022 8 2133 20 EPIGENETIC INACTIVATION OF THE MIR-34A IN HEMATOLOGICAL MALIGNANCIES. MIR-34A IS A TRANSCRIPTIONAL TARGET OF P53 AND IMPLICATED IN CARCINOGENESIS. WE STUDIED THE ROLE OF MIR-34A METHYLATION IN A PANEL OF HEMATOLOGICAL MALIGNANCIES INCLUDING ACUTE LEUKEMIA [ACUTE MYELOID LEUKEMIA (AML) AND ACUTE LYMPHOBLASTIC LEUKEMIA (ALL)], CHRONIC LEUKEMIA [CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AND CHRONIC MYELOID LEUKEMIA (CML)], MULTIPLE MYELOMA (MM) AND NON-HODGKIN'S LYMPHOMA (NHL). THE METHYLATION STATUS OF MIR-34A PROMOTER WAS STUDIED IN 12 CELL LINES AND 188 DIAGNOSTIC SAMPLES BY METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION. MIR-34A PROMOTER WAS UNMETHYLATED IN NORMAL CONTROLS BUT METHYLATED IN 75% LYMPHOMA AND 37% MYELOMA CELL LINES. HYPOMETHYLATING TREATMENT LED TO RE-EXPRESSION OF PRI-MIR-34A TRANSCRIPT IN LYMPHOMA CELLS WITH HOMOZYGOUS MIR-34A METHYLATION. IN PRIMARY SAMPLES AT DIAGNOSIS, MIR-34A METHYLATION WAS DETECTED IN 4% CLL, 5.5% MM SAMPLES AND 18.8% OF NHL AT DIAGNOSIS BUT NONE OF ALL, AML AND CML (P = 0.011). IN MM PATIENTS WITH PAIRED SAMPLES, MIR-34A METHYLATION STATUS REMAINED UNCHANGED AT PROGRESSION. AMONGST LYMPHOID MALIGNANCIES, MIR-34A WAS PREFERENTIALLY METHYLATED IN NHL (P = 0.018), IN PARTICULAR NATURAL KILLER (NK)/T-CELL LYMPHOMA. IN CONCLUSION, AMONGST HEMATOLOGICAL MALIGNANCIES, MIR-34A METHYLATION IS PREFERENTIALLY HYPERMETHYLATED IN NHL, IN PARTICULAR NK/T-CELL LYMPHOMA, IN A TUMOR-SPECIFIC MANNER, THEREFORE THE ROLE OF MIR-34A IN LYMPHOMAGENESIS WARRANTS FURTHER STUDY. 2010 9 5243 26 PROGNOSTIC IMPACT OF EPIGENETIC CLASSIFICATION IN CHRONIC LYMPHOCYTIC LEUKEMIA: THE CASE OF SUBSET #2. BASED ON THE METHYLATION STATUS OF 5 SINGLE CPG SITES, A NOVEL EPIGENETIC CLASSIFICATION OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) WAS RECENTLY PROPOSED, CLASSIFYING CLL PATIENTS INTO 3 CLINICO-BIOLOGICAL SUBGROUPS WITH DIFFERENT OUTCOME, TERMED MEMORY LIKE CLL (M-CLL), NAIVE LIKE CLL (N-CLL), AND A THIRD INTERMEDIATE CLL SUBGROUP (I-CLL). WHILE M-CLL AND N-CLL PATIENTS AT LARGE CORRESPONDED TO PATIENTS CARRYING MUTATED AND UNMUTATED IGHV GENES, RESPECTIVELY, LIMITED INFORMATION EXISTS REGARDING THE LESS DEFINED I-CLL GROUP. USING PYROSEQUENCING, WE INVESTIGATED THE PROGNOSTIC IMPACT OF THE PROPOSED 5 CPG SIGNATURE IN A WELL-CHARACTERIZED CLL COHORT (135 CASES), INCLUDING IGHV-MUTATED AND UNMUTATED PATIENTS AS WELL AS CLINICALLY AGGRESSIVE STEREOTYPED SUBSET #2 PATIENTS. OVERALL, WE CONFIRMED THE SIGNATURE'S ASSOCIATION WITH ESTABLISHED PROGNOSTIC MARKERS. MOREOVER, IN THE PRESENCE OF THE IGHV MUTATIONAL STATUS, THE EPIGENETIC SIGNATURE REMAINED INDEPENDENTLY ASSOCIATED WITH BOTH TIME-TO-FIRST-TREATMENT AND OVERALL SURVIVAL IN MULTIVARIATE ANALYSES. AS A PRIME FINDING, WE OBSERVED THAT SUBSET #2 PATIENTS WERE PREDOMINANTLY CLASSIFIED AS I-CLL, PROBABLY REFLECTING THEIR BORDERLINE IGHV MUTATIONAL STATUS (97-99% GERMLINE IDENTITY), THOUGH HAVING A SIMILARLY POOR PROGNOSIS AS N-CLL PATIENTS. IN SUMMARY, WE VALIDATED THE EPIGENETIC CLASSIFIER AS AN INDEPENDENT FACTOR IN CLL PROGNOSTICATION AND PROVIDE FURTHER EVIDENCE THAT SUBSET #2 IS A MEMBER OF THE I-CLL GROUP, HENCE SUPPORTING THE EXISTENCE OF A THIRD, INTERMEDIATE EPIGENETIC SUBGROUP. 2016 10 2131 19 EPIGENETIC INACTIVATION OF THE HSA-MIR-203 IN HAEMATOLOGICAL MALIGNANCIES. MIR-203 IS A TUMOUR SUPPRESSOR MICRORNA (MIRNA). WE STUDIED THE METHYLATION OF HSA-MIR-203 IN 150 SAMPLES INCLUDING ACUTE MYELOID LEUKAEMIA (AML), ACUTE LYMPHOBLASTIC LEUKAEMIA (ALL), CHRONIC MYELOID LEUKAEMIA (CML), CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) AND NON-HODGKIN'S LYMPHOMA (NHL) BY METHYLATION-SPECIFIC PCR, AND MIRNA EXPRESSION BY STEM-LOOP RT-QPCR. HSA-MIR-203 PROMOTER WAS UNMETHYLATED IN NORMAL CONTROLS BUT HOMOZYGOUSLY METHYLATED IN TWO AML AND FOUR LYMPHOMA CELL LINES, IN WHICH 5-AZA-2'-DEOXYCYTIDINE TREATMENT LED TO PROMOTER DEMETHYLATION AND MIR-203 RE-EXPRESSION. RESTORATION OF MIR-203 EXPRESSION IN LYMPHOMA CELLS INHIBITED CELLULAR PROLIFERATION AND INCREASED CELL DEATH, SUGGESTING AN INHERENT TUMOUR SUPPRESSOR ACTIVITY. IN PRIMARY SAMPLES, HSA-MIR-203 METHYLATION WAS ABSENT IN CML BUT DETECTED IN 5.0% ALL, 10.0% AML, 42.0% CLL AND 38.8% OF NHL (INCLUDING SIX [60.0%] NATURAL KILLER-CELL, NINE [40.9%] B-CELL AND FOUR [23.5%] T CELL NHL). MOREOVER, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH HYPERMETHYLATION OF HSA-MIR-34A, -124A AND -196B IN NHL BUT NOT CLL. IN CLL, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH A HIGHER PRESENTING HB LEVEL (P = 0.033). THE PROJECTED 10 YEAR OVERALL SURVIVAL OF THE CLL PATIENTS WAS 58.2%, WHICH WAS IMPACTED BY RAI STAGE AND HIGH-RISK KARYOTYPES BUT NOT HSA-MIR-203 METHYLATION. HSA-MIR-203 WAS MORE FREQUENTLY METHYLATED IN LYMPHOID THAN MYELOID MALIGNANCIES (P = 0.002). IN CONCLUSION, MIR-203, A TUMOUR SUPPRESSOR GENE, WAS HYPERMETHYLATED IN A TUMOUR-SPECIFIC MANNER WITH GENE SILENCING. HSA-MIR-203 WAS MORE FREQUENTLY HYPERMETHYLATED IN LYMPHOID THAN MYELOID MALIGNANCIES. IN NHL, HSA-MIR-203 METHYLATION WAS ASSOCIATED WITH CONCOMITANT METHYLATION OF OTHER TUMOUR SUPPRESSOR MIRNAS. THE FREQUENT HSA-MIR-203 METHYLATION IN LYMPHOID MALIGNANCIES SUGGESTED A PATHOGENETIC ROLE OF HSA-MIR-203 METHYLATION. 2011 11 4874 28 OVERCOMING ACQUIRED EPIGENETIC RESISTANCE TO BTK INHIBITORS. THE USE OF BRUTON TYROSINE KINASE (BTK) INHIBITORS TO BLOCK B-CELL RECEPTOR (BCR)-DEPENDENT NF-KAPPAB ACTIVATION IN LYMPHOID MALIGNANCIES HAS BEEN A MAJOR CLINICAL ADVANCE, YET ACQUIRED THERAPEUTIC RESISTANCE IS A RECURRING PROBLEM. WE MODELED THE DEVELOPMENT OF RESISTANCE TO THE BTK INHIBITOR IBRUTINIB IN THE ACTIVATED B-CELL (ABC) SUBTYPE OF DIFFUSE LARGE B-CELL LYMPHOMA, WHICH RELIES ON CHRONIC ACTIVE BCR SIGNALING FOR SURVIVAL. THE PRIMARY MODE OF RESISTANCE WAS EPIGENETIC, DRIVEN IN PART BY THE TRANSCRIPTION FACTOR TCF4. THE RESULTANT PHENOTYPIC SHIFT ALTERED BCR SIGNALING SUCH THAT THE GTPASE RAC2 SUBSTITUTED FOR BTK IN THE ACTIVATION OF PHOSPHOLIPASE CGAMMA2, THEREBY SUSTAINING NF-KAPPAB ACTIVITY. THE INTERACTION OF RAC2 WITH PHOSPHOLIPASE CGAMMA2 WAS ALSO INCREASED IN CHRONIC LYMPHOCYTIC LEUKEMIA CELLS FROM PATIENTS WITH PERSISTENT OR PROGRESSIVE DISEASE ON BTK INHIBITOR TREATMENT. WE IDENTIFIED CLINICALLY AVAILABLE DRUGS THAT CAN TREAT EPIGENETIC IBRUTINIB RESISTANCE, SUGGESTING COMBINATION THERAPEUTIC STRATEGIES. SIGNIFICANCE: IN DIFFUSE LARGE B-CELL LYMPHOMA, WE SHOW THAT PRIMARY RESISTANCE TO BTK INHIBITORS IS DUE TO EPIGENETIC RATHER THAN GENETIC CHANGES THAT CIRCUMVENT THE BTK BLOCKADE. WE ALSO OBSERVED THIS RESISTANCE MECHANISM IN CHRONIC LYMPHOCYTIC LEUKEMIA, SUGGESTING THAT EPIGENETIC ALTERATIONS MAY CONTRIBUTE MORE TO BTK INHIBITOR RESISTANCE THAN CURRENTLY THOUGHT.SEE RELATED COMMENTARY BY PASQUALUCCI, P. 555. THIS ARTICLE IS HIGHLIGHTED IN THE IN THIS ISSUE FEATURE, P. 549. 2021 12 5229 26 PRO-APOPTOTIC TP53 HOMOLOG TAP63 IS REPRESSED VIA EPIGENETIC SILENCING AND B-CELL RECEPTOR SIGNALLING IN CHRONIC LYMPHOCYTIC LEUKAEMIA. CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) IS AN ACCUMULATIVE DISORDER MARKED BY DEFICIENT APOPTOSIS. THE TP53 HOMOLOG TAP63 PROMOTES APOPTOSIS AND CHEMOSENSITIVITY IN SOLID TUMOURS AND ITS DEREGULATION MAY CONTRIBUTE TO CLL CELL SURVIVAL. WE FOUND THAT TAP63ALPHA WAS THE MOST PREVALENT TP63 ISOFORM IN CLL. COMPARED TO HEALTHY B CELLS, TAP63 MRNA WAS REPRESSED IN 55.7% OF CLL SAMPLES. TP63 PROMOTER METHYLATION WAS HIGH IN CLL AND INVERSELY CORRELATED WITH TP63 PROTEIN EXPRESSION IN B-CELL LYMPHOMA CELL LINES. SIRNA-MEDIATED KNOCKDOWN OF TP63 RESULTED IN PARTIAL PROTECTION FROM SPONTANEOUS APOPTOSIS ACCOMPANIED BY REDUCTIONS IN PMAIP1 (NOXA), BBC3 (PUMA), AND BAX MRNA IN CLL CELLS AND INCREASED PROLIFERATION OF RAJI LYMPHOMA CELLS. TAP63 MRNA LEVELS WERE HIGHER IN CLL WITH UNMUTATED IGHV. B-CELL RECEPTOR (BCR) ENGAGEMENT LED TO REPRESSION OF TP63 MRNA EXPRESSION IN MALIGNANT B CELLS, WHILE PHARMACOLOGICAL INHIBITION OF BCR SIGNALLING PREVENTED TP63 DOWNREGULATION. MIR21, KNOWN TO TARGET TAP63, CORRELATED INVERSELY WITH TAP63 EXPRESSION IN CLL, AND BCR-MEDIATED DOWNREGULATION OF TP63 WAS ACCOMPANIED BY MIR21 UPREGULATION IN MOST CLL SAMPLES. OUR DATA ILLUSTRATE THE PRO-APOPTOTIC FUNCTION OF TP63, PROVIDE INSIGHTS INTO THE MECHANISMS OF BCR-TARGETING AGENTS, AND ESTABLISH A RATIONALE FOR DESIGNING NOVEL APPROACHES TO INDUCE TP63 IN CLL AND B-CELL LYMPHOMA. 2013 13 3902 30 LEARNING FROM THE FAILURES OF DRUG DISCOVERY IN B-CELL NON-HODGKIN LYMPHOMAS AND PERSPECTIVES FOR THE FUTURE: CHRONIC LYMPHOCYTIC LEUKEMIA AND DIFFUSE LARGE B-CELL LYMPHOMA AS TWO ENDS OF A SPECTRUM IN DRUG DEVELOPMENT. DESPITE SUBSTANTIAL RECENT ADVANCES, THERE IS STILL AN UNMET NEED FOR BETTER THERAPIES IN B-CELL NON HODGKIN LYMPHOMAS (B-NHL), ESPECIALLY IN RELAPSED OR REFRACTORY DISEASE. MANY NOVEL TARGETED DRUGS HAVE BEEN DEVELOPED BASED ON A BETTER MOLECULAR UNDERSTANDING OF B-NHL. AREAS COVERED: THIS ARTICLE FOCUSES ON CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) AS A REPRESENTATIVE FOR INDOLENT LYMPHOMAS AND PARADIGMATIC FOR THE TREMENDOUS PROGRESS IN TREATING B-NHL ON THE ONE HAND AND DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL) AS A REPRESENTATIVE FOR AGGRESSIVE LYMPHOMAS AND PARADIGMATIC FOR MANY UNSOLVED PROBLEMS IN LYMPHOMA TREATMENT OR THE OTHER HAND. WE HIGHLIGHT SALIENT POINTS IN CURRENT THERAPIES TARGETING GENETIC, EPIGENETIC, IMMUNOLOGICAL AND MICROENVIRONMENTAL ALTERATIONS. POSSIBLE REASONS FOR DRUG FAILURE IN CLINICAL TRIALS LIKE TUMOR HETEROGENEITY, CLONAL EVOLUTION AND DRUG RESISTANCE MECHANISMS ARE DISCUSSED. BASED THEREON, SOME PERSPECTIVES FOR FURTHER DRUG DISCOVERY ARE GIVEN. EXPERT OPINION: IN VIEW OF THE PATHOGENETIC COMPLEXITY OF LYMPHOMAS, THERAPIES TARGETING EXCLUSIVELY A SINGLE ALTERATION MAY FAIL BECAUSE RESISTANCE MECHANISMS ARE PRESENT EITHER INITIALLY OR EVOLVE DURING TREATMENT. THEREFORE, FUTURE THERAPIES IN B-NHL MAY HAVE TO TARGET THE GREATEST POSSIBLE NUMBER OF GENETIC, IMMUNOLOGICAL OR EPIGENETIC ALTERATIONS STILL ALLOWING TOLERABILITY AND TO MONITOR THESE ALTERATIONS DURING THERAPY. 2017 14 557 27 B-CELL ANTIGEN RECEPTOR SIGNALING IN CHRONIC LYMPHOCYTIC LEUKEMIA: THERAPEUTIC TARGETS AND TRANSLATIONAL OPPORTUNITIES. B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY CLONALLY EXPANDED AND MOLECULARLY HETEROGENEOUS POPULATIONS OF B LYMPHOCYTES WITH IMPAIRED APOPTOTIC MECHANISMS. THIS OCCURS AS A RESULT OF MULTIPLE GENETIC AND EPIGENETIC ABNORMALITIES, INCLUDING CHROMOSOMAL ABERRATIONS AND ENHANCER REGION HYPOMETHYLATION, OFTEN IMPINGING ON INTRACELLULAR SIGNALING PATHWAYS THAT ARE ESSENTIAL TO NORMAL B-CELL ACTIVATION, PROLIFERATION, AND SURVIVAL. THE B-CELL ANTIGEN RECEPTOR (BCR) SIGNALING IS ONE SUCH PATHWAY USURPED BY MALIGNANT B CELLS, AS EXEMPLIFIED BY THE EARLY PHASE CLINICAL SUCCESS ACHIEVED BY SMALL-MOLECULE AGENTS TARGETING KEY PLAYERS INVOLVED IN THE PATHWAY. SUCH NEW TARGETED AGENTS, INCLUDING THOSE THAT INHIBIT THE FUNCTION OF SPLEEN TYROSINE KINASE (SYK), BRUTON'S TYROSINE KINASE (BTK), PHOSPHATIDYLINOSITOL 3-KINASES (PI3K), AND B-CELL LYMPHOMA 2 (BCL-2), ALONG WITH THE CURRENT STANDARD THERAPY COMPRISING CHEMO-IMMUNOTHERAPIES WITH OR WITHOUT B-CELL DEPLETING BIOLOGIC AGENT RITUXIMAB (ANTI-CD20 MONOCLONAL ANTIBODY), SHOULD EXPAND THE ARMAMENTARIUM FOR CLL THERAPY. WE REVIEW THE THERAPEUTIC AGENTS CURRENTLY IN CLINICAL DEVELOPMENT WHICH TARGET DIFFERENT EFFECTORS OF THE MALIGNANT BCR SIGNALING, AND DISCUSS THEIR OVERLAPPING AND DISCRIMINATING TRANSLATIONAL OPPORTUNITIES IN THE CONTEXT OF CLL TREATMENT. 2013 15 941 33 CHRONIC LYMPHOCYTIC LEUKEMIA B-CELL NORMAL CELLULAR COUNTERPART: CLUES FROM A FUNCTIONAL PERSPECTIVE. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY THE CLONAL EXPANSION OF SMALL MATURE-LOOKING CD19+ CD23+ CD5+ B-CELLS THAT ACCUMULATE IN THE BLOOD, BONE MARROW, AND LYMPHOID ORGANS. TO DATE, NO CONSENSUS HAS BEEN REACHED CONCERNING THE NORMAL CELLULAR COUNTERPART OF CLL B-CELLS AND SEVERAL B-CELL TYPES HAVE BEEN PROPOSED. CLL B-CELLS HAVE REMARKABLE PHENOTYPIC AND GENE EXPRESSION PROFILE HOMOGENEITY. IN RECENT YEARS, THE MOLECULAR AND CELLULAR BIOLOGY OF CLL HAS BEEN ENRICHED BY SEMINAL INSIGHTS THAT ARE LEADING TO A BETTER UNDERSTANDING OF THE NATURAL HISTORY OF THE DISEASE. IMMUNOPHENOTYPIC AND MOLECULAR APPROACHES (INCLUDING IMMUNOGLOBULIN HEAVY-CHAIN VARIABLE GENE MUTATIONAL STATUS, TRANSCRIPTIONAL AND EPIGENETIC PROFILING) COMPARING THE NORMAL B-CELL SUBSET AND CLL B-CELLS PROVIDE SOME NEW INSIGHTS INTO THE NORMAL CELLULAR COUNTERPART. FUNCTIONAL CHARACTERISTICS (INCLUDING ACTIVATION REQUIREMENTS AND PROPENSITY FOR PLASMA CELL DIFFERENTIATION) OF CLL B-CELLS HAVE NOW BEEN INVESTIGATED FOR 50 YEARS. B-CELL SUBSETS DIFFER SUBSTANTIALLY IN TERMS OF THEIR FUNCTIONAL FEATURES. ANALYSIS OF SHARED FUNCTIONAL CHARACTERISTICS MAY REVEAL SIMILARITIES BETWEEN NORMAL B-CELL SUBSETS AND CLL B-CELLS, ALLOWING SPECULATIVE ASSIGNMENT OF A NORMAL CELLULAR COUNTERPART FOR CLL B-CELLS. IN THIS REVIEW, WE SUMMARIZE CURRENT DATA REGARDING PERIPHERAL B-CELL DIFFERENTIATION AND HUMAN B-CELL SUBSETS AND SUGGEST POSSIBILITIES FOR A NORMAL CELLULAR COUNTERPART BASED ON THE FUNCTIONAL CHARACTERISTICS OF CLL B-CELLS. HOWEVER, A DEFINITIVE NORMAL CELLULAR COUNTERPART CANNOT BE ATTRIBUTED ON THE BASIS OF THE AVAILABLE DATA. WE DISCUSS THE FUNCTIONAL CHARACTERISTICS REQUIRED FOR A CELL TO BE LOGICALLY CONSIDERED TO BE THE NORMAL COUNTERPART OF CLL B-CELLS. 2018 16 5666 25 SF3B1-MUTATED CHRONIC LYMPHOCYTIC LEUKEMIA SHOWS EVIDENCE OF NOTCH1 PATHWAY ACTIVATION INCLUDING CD20 DOWNREGULATION. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS CHARACTERIZED BY A LOW CD20 EXPRESSION, IN PART EXPLAINED BY AN EPIGENETIC-DRIVEN DOWNREGULATION TRIGGERED BY MUTATIONS OF THE NOTCH1 GENE. IN THE PRESENT STUDY, BY TAKING ADVANTAGE OF A WIDE AND WELL-CHARACTERIZED CLL COHORT (N=537), WE DEMONSTRATE THAT CD20 EXPRESSION IS DOWNREGULATED IN SF3B1-MUTATED CLL IN AN EXTENT SIMILAR TO NOTCH1-MUTATED CLL. IN FACT, SF3B1-MUTATED CLL CELLS SHOW COMMON FEATURES WITH NOTCH1-MUTATED CLL CELLS, INCLUDING A GENE EXPRESSION PROFILE ENRICHED OF NOTCH1-RELATED GENE SETS AND ELEVATED EXPRESSION OF THE ACTIVE INTRACYTOPLASMIC NOTCH1. ACTIVATION OF THE NOTCH1 SIGNALING AND DOWN-REGULATION OF SURFACE CD20 IN SF3B1-MUTATED CLL CELLS CORRELATE WITH OVER-EXPRESSION OF AN ALTERNATIVELY SPLICED FORM OF DVL2, A COMPONENT OF THE WNT PATHWAY AND NEGATIVE REGULATOR OF THE NOTCH1 PATHWAY. THESE FINDINGS ARE CONFIRMED BY SEPARATELY ANALYZING THE CD20-DIM AND CD20-BRIGHT CELL FRACTIONS FROM SF3B1-MUTATED CASES AS WELL AS BY DVL2 KNOCK-OUT EXPERIMENTS IN CLL-LIKE CELL MODELS. ALTOGETHER, THE CLINICAL AND BIOLOGICAL FEATURES THAT CHARACTERIZE NOTCH1-MUTATED CLL MAY ALSO BE RECAPITULATED IN SF3B1-MUTATED CLL, CONTRIBUTING TO EXPLAIN THE POOR PROGNOSIS OF THIS CLL SUBSET AND PROVIDING THE RATIONALE FOR EXPANDING NOVEL AGENTS-BASED THERAPIES TO SF3B1-MUTATED CLL. 2021 17 3520 31 IGLV3-21R110 IDENTIFIES AN AGGRESSIVE BIOLOGICAL SUBTYPE OF CHRONIC LYMPHOCYTIC LEUKEMIA WITH INTERMEDIATE EPIGENETICS. B-CELL RECEPTOR (BCR) SIGNALING IS CRUCIAL FOR CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) BIOLOGY. IGLV3-21-EXPRESSING B CELLS MAY ACQUIRE A SINGLE POINT MUTATION (R110) THAT TRIGGERS AUTONOMOUS BCR SIGNALING, CONFERRING AGGRESSIVE BEHAVIOR. EPIGENETIC STUDIES HAVE DEFINED 3 CLL SUBTYPES BASED ON METHYLATION SIGNATURES REMINISCENT OF NAIVE-LIKE (N-CLL), INTERMEDIATE (I-CLL), AND MEMORY-LIKE (M-CLL) B CELLS WITH DIFFERENT BIOLOGICAL FEATURES. I-CLL CARRIES A BORDERLINE IGHV MUTATIONAL LOAD AND SIGNIFICANTLY HIGHER USE OF IGHV3-21/IGLV3-21. TO DETERMINE THE CLINICAL AND BIOLOGICAL FEATURES OF IGLV3-21R110 CLL AND ITS RELATIONSHIP TO THESE EPIGENETIC SUBTYPES, WE CHARACTERIZED THE IMMUNOGLOBULIN GENE OF 584 CLL CASES USING WHOLE-GENOME/EXOME AND RNA SEQUENCING. IGLV3-21R110 WAS DETECTED IN 6.5% OF CASES: 30 (38%) OF 79 I-CLLS, 5 (1.7%) OF 291 M-CLLS, AND 1 (0.5%) OF 189 N-CLLS. ALL STEREOTYPE SUBSET 2 CASES CARRIED IGLV3-21R110, WHEREAS 62% OF IGLV3-21R110 I-CLL CASES HAD NONSTEREOTYPED BCR IMMUNOGLOBULINS. IGLV3-21R110 I-CLL HAD A SIGNIFICANTLY HIGHER NUMBER OF SF3B1 AND ATM MUTATIONS AND TOTAL NUMBER OF DRIVER ALTERATIONS. HOWEVER, THE R110 MUTATION WAS THE SOLE ALTERATION IN 1 I-CLL AND WAS ACCOMPANIED ONLY BY DEL(13Q) IN 3. ALTHOUGH IGHV MUTATIONAL STATUS VARIED, IGLV3-21R110 I-CLL TRANSCRIPTOMICALLY RESEMBLED N-CLL/UNMUTATED IGHV CLL WITH A SPECIFIC SIGNATURE INCLUDING WNT5A/B OVEREXPRESSION. IN CONTRAST, I-CLL LACKING IGLV3-21R110 MIRRORED M-CLL/MUTATED IGHV. PATIENTS WITH IGLV3-21R110 I-CLL HAD A SHORT TIME TO FIRST TREATMENT AND OVERALL SURVIVAL SIMILAR TO THOSE OF N-CLL/UNMUTATED IGHV PATIENTS, WHEREAS PATIENTS WITH NON-IGLV3-21R110 I-CLL HAD A GOOD PROGNOSIS SIMILAR TO THAT OF PATIENTS WITH M-CLL/MUTATED IGHV. IGLV3-21R110 DEFINES A CLL SUBGROUP WITH SPECIFIC BIOLOGICAL FEATURES AND AN UNFAVORABLE PROGNOSIS INDEPENDENT OF IGHV MUTATIONAL STATUS AND EPIGENETIC SUBTYPE. 2021 18 147 31 ABERRANT EPIGENETIC GENE REGULATION IN LYMPHOID MALIGNANCIES. IN LYMPHOID MALIGNANCIES, ABERRANT EPIGENETIC MECHANISMS SUCH AS DNA METHYLATION AND HISTONE MODIFICATIONS INFLUENCE CHROMATIN ARCHITECTURE AND CAN RESULT IN ALTERED GENE EXPRESSION. THESE ALTERATIONS COMMONLY AFFECT GENES THAT PLAY IMPORTANT ROLES IN THE CELL CYCLE, APOPTOSIS, AND DNA REPAIR IN NON-HODGKIN LYMPHOMA (NHL). THE ABILITY TO IDENTIFY EPIGENETIC MODIFICATIONS TO THESE IMPORTANT GENES HAS INCREASED EXPONENTIALLY DUE TO ADVANCES IN TECHNOLOGY. AS A RESULT, THERE ARE WELL-DEFINED, GENE-SPECIFIC EPIGENETIC ABERRATIONS ASSOCIATED WITH NHL COMPRISING FOLLICULAR LYMPHOMA (FL), MANTLE CELL LYMPHOMA (MCL), CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), AND DIFFUSE LARGE B-CELL LYMPHOMA (DLBCL). THE IDENTIFICATION OF THESE GENES IS IMPORTANT BECAUSE THEY MAY BE USED AS BIOMARKERS FOR PROGNOSIS, DIAGNOSIS AND IN DEVELOPING IMPROVED TREATMENT STRATEGIES. ALSO IMPORTANT, IN THE CONTROL OF GENE EXPRESSION, IS THE PACKAGING OF DNA WITHIN THE NUCLEUS OF A CELL. THIS PACKAGING CAN BE DISTORTED BY EPIGENETIC ALTERATIONS AND MAY ALTER THE ACCESSIBILITY OF CERTAIN REGIONS OF THE GENOME IN CANCER CELLS. THIS REVIEW DISCUSSES THE IMPACT OF KNOWN EPIGENETIC ABERRATION ON THE REGULATION OF GENE EXPRESSION IN NHL AND PROVIDES INSIGHT INTO THE SPATIAL CONFORMATION OF THE GENOME (DNA PACKAGING) IN ACUTE LYMPHOBLASTIC LEUKEMIA. 2013 19 27 28 A B-CELL EPIGENETIC SIGNATURE DEFINES THREE BIOLOGIC SUBGROUPS OF CHRONIC LYMPHOCYTIC LEUKEMIA WITH CLINICAL IMPACT. PROSPECTIVE IDENTIFICATION OF PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) DESTINED TO PROGRESS WOULD GREATLY FACILITATE THEIR CLINICAL MANAGEMENT. RECENTLY, WHOLE-GENOME DNA METHYLATION ANALYSES IDENTIFIED THREE CLINICOBIOLOGIC CLL SUBGROUPS WITH AN EPIGENETIC SIGNATURE RELATED TO DIFFERENT NORMAL B-CELL COUNTERPARTS. HERE, WE DEVELOPED A CLINICALLY APPLICABLE METHOD TO IDENTIFY THESE SUBGROUPS AND TO STUDY THEIR CLINICAL RELEVANCE. USING A SUPPORT VECTOR MACHINE APPROACH, WE BUILT A PREDICTION MODEL USING FIVE EPIGENETIC BIOMARKERS THAT WAS ABLE TO CLASSIFY CLL PATIENTS ACCURATELY INTO THE THREE SUBGROUPS, NAMELY NAIVE B-CELL-LIKE, INTERMEDIATE AND MEMORY B-CELL-LIKE CLL. DNA METHYLATION WAS QUANTIFIED BY HIGHLY REPRODUCIBLE BISULFITE PYROSEQUENCING ASSAYS IN TWO INDEPENDENT CLL SERIES. IN THE INITIAL SERIES (N=211), THE THREE SUBGROUPS SHOWED DIFFERENTIAL LEVELS OF IGHV (IMMUNOGLOBULIN HEAVY-CHAIN LOCUS) MUTATION (P<0.001) AND VH USAGE (P<0.03), AS WELL AS DIFFERENT CLINICAL FEATURES AND OUTCOME IN TERMS OF TIME TO FIRST TREATMENT (TTT) AND OVERALL SURVIVAL (P<0.001). A MULTIVARIATE COX MODEL SHOWED THAT EPIGENETIC CLASSIFICATION WAS THE STRONGEST PREDICTOR OF TTT (P<0.001) ALONG WITH BINET STAGE (P<0.001). THESE FINDINGS WERE CORROBORATED IN A VALIDATION SERIES (N=97). IN THIS STUDY, WE DEVELOPED A SIMPLE AND ROBUST METHOD USING EPIGENETIC BIOMARKERS TO CATEGORIZE CLLS INTO THREE SUBGROUPS WITH DIFFERENT CLINICOBIOLOGIC FEATURES AND OUTCOME. 2015 20 6373 19 THE ROLE OF MIRNAS AND EPIGENETIC MECHANISMS IN PRIMARY GASTRIC MUCOSA-ASSOCIATED LYMPHOID TISSUE LYMPHOMA. GASTRIC MUCOSA-ASSOCIATED LYMPHOID TISSUE (MALT) LYMPHOMA IS A RARE LOW-GRADE B-CELL NON-HODGKIN LYMPHOMA ASSOCIATED WITH HELICOBACTER PYLORI INFECTION AND THE SUBSEQUENT CHRONIC INFLAMMATION. SIGNIFICANT PROGRESS IN UNDERSTANDING THE PATHOGENESIS OF THE DISEASE HAS ALREADY BEEN MADE. HOWEVER, THE EXACT MOLECULAR PATHWAYS OF LYMPHOMAGENESIS REMAIN UNCLEAR. FURTHERMORE, DIFFICULTIES REGARDING ACCURATE DIAGNOSIS OF GASTRIC MALT LYMPHOMA AND ITS DISCRIMINATION FROM GASTRITIS OR OTHER LYMPHOMA SUBTYPES ARISE. RECENT STUDIES EVALUATE THE ROLE OF MIRNAS AND EPIGENETIC ALTERATIONS ON MALT LYMPHOMA PATHOGENESIS AND PROGNOSIS. THIS REVIEW CRITICALLY SUMMARIZES THE MOST IMPORTANT DATA ON THE ROLE OF MIRNAS AND EPIGENETICS IN MALT LYMPHOMAS PATHOGENESIS, PROGNOSIS AND TREATMENT. 2016