1 4907 121 P53 ABERRATIONS DO NOT PREDICT INDIVIDUAL RESPONSE TO FLUDARABINE IN PATIENTS WITH B-CELL CHRONIC LYMPHOCYTIC LEUKAEMIA IN ADVANCED STAGES RAI III/IV. ABNORMALITIES OF P53 HAVE BEEN ASSOCIATED WITH SHORT SURVIVAL AND NON-RESPONSE TO THERAPY IN CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL). WE HAVE EVALUATED THE RATE OF RESPONSE TO FLUDARABINE AS FIRST-LINE THERAPY IN 54 PATIENTS WITH ADVANCED STAGE CLL, ANALYSING THE CYTOGENETIC PROFILE, ABERRATIONS IN P53, INCLUDING THE METHYLATION STATUS OF ITS PROMOTER, AND THE IMMUNOGLOBULIN HEAVY-CHAIN VARIABLE-REGION (IGVH) MUTATION STATUS. ACCORDING TO THE ADVANCED STAGE OF THE DISEASE IN THIS SERIES, 75% OF PATIENTS PRESENTED GENETIC ABERRATIONS ASSOCIATED WITH POOR PROGNOSIS: DEL(17P) AND/OR DEL(11Q), AND NO-MUTATED IGVH GENES. TEN PATIENTS (18.5%) HAD METHYLATION IN THE PROMOTER REGION OF P53. EIGHTY-THREE PER CENT OF PATIENTS TREATED ACHIEVED A RESPONSE, WITH A HIGH RATE OF COMPLETE REMISSION (47.6%). ALTHOUGH WE FOUND A SIGNIFICANT CORRELATION BETWEEN FAILURES AND THE PRESENCE OF P53 ABERRATIONS (P = 0.0065), EITHER WITH METHYLATION (P = 0.018) OR DELETION (P = 0.015), 64% OF THE PATIENTS WITH ABERRATIONS IN THIS GENE RESPONDED TO TREATMENT (11/17), SUGGESTING THAT FLUDARABINE INDUCES HIGH REMISSION RATES, EVEN IN THESE PATIENTS. THIS IS THE FIRST TIME THAT THE SIGNIFICANCE OF P53 PROMOTER METHYLATION STATUS IS DESCRIBED IN THIS PATHOLOGY, AND OUR DATA SUPPORT THAT THIS EPIGENETIC PHENOMENON COULD BE INVOLVED IN THE PATHOGENESIS AND CLINICAL EVOLUTION OF CLL. 2005 2 2753 39 EXPRESSION OF BCL2L12 IN CHRONIC LYMPHOCYTIC LEUKEMIA PATIENTS: ASSOCIATION WITH CLINICAL AND MOLECULAR PROGNOSTIC MARKERS. DYSREGULATION OF APOPTOSIS IS A DISTINCTIVE FEATURE OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), ALTHOUGH A UNIQUE MECHANISM UNDERLYING APOPTOSIS RESISTANCE OF CLL B LYMPHOCYTES HAS NOT BEEN IDENTIFIED YET. ABERRANT EXPRESSION AS WELL AS GENETIC AND EPIGENETIC ALTERATIONS OF NUMEROUS GENES INVOLVED IN DIFFERENT PATHWAYS OF APOPTOSIS REGULATION HAS BEEN DESCRIBED IN CLL. HERE, WE REPORT THE EXPRESSION ANALYSIS OF BCL2L12 (BCL2-LIKE 12), A NOVEL APOPTOTIC GENE BELONGING TO BCL2 FAMILY, IN 58 SERBIAN CLL PATIENTS. QUANTITATIVE REVERSE-TRANSCRIPTASE POLYMERASE CHAIN REACTION (QRT-PCR) ANALYSIS REVEALED A SIGNIFICANT OVEREXPRESSION OF BCL2L12 MRNA IN CLL SAMPLES COMPARED TO NON-LEUKEMIC SAMPLES, IMPLYING ITS ROLE IN THE PATHOGENESIS OF THE DISEASE. RECEIVER OPERATING CHARACTERISTIC (ROC) ANALYSIS SHOWED THAT BCL2L12 EXPRESSION EFFICIENTLY DISCRIMINATES CLL CASES FROM HEALTHY CONTROLS. HOWEVER, RELATIVELY HOMOGENOUS BCL2L12 MRNA EXPRESSION AMONG PATIENTS DID NOT REFLECT THEIR CLINICAL CHARACTERISTICS (WITH THE EXCEPTION OF LACTATE DEHYDROGENASE STATUS AND TIME FROM DIAGNOSIS TO TREATMENT) AND FAILED TO SHOW ASSOCIATION WITH THE MOST INFORMATIVE PROGNOSTIC MARKERS, NAMELY THE MUTATIONAL STATUS OF REARRANGED IMMUNOGLOBULIN HEAVY CHAIN VARIABLE REGION GENES, CD38 AND LIPOPROTEIN LIPASE GENE (LPL) EXPRESSION. 2013 3 27 31 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 4 1473 38 DISTINCT PATTERNS OF GLOBAL PROMOTER METHYLATION IN EARLY STAGE CHRONIC LYMPHOCYTIC LEUKEMIA. GENOMIC AND EPIGENOMIC STUDIES OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) ARE RESHAPING OUR UNDERSTANDING OF THE DISEASE AND HAVE PROVIDED NEW PERSPECTIVES FOR A MORE INDIVIDUALIZED DIAGNOSIS AND NEW POTENTIAL THERAPEUTIC TARGETS. IN THIS STUDY, THE GLOBAL PROMOTER METHYLATION PROFILE WAS DETERMINED IN HIGHLY PURIFIED B-CELLS FROM 37 (BINET STAGE A) CLL PATIENTS, USING HIGH-RESOLUTION METHYLATION MICROARRAYS (27,578 CPG). OVERALL, THE METHYLATION PATTERN CORRELATED WITH THE MAJOR BIOLOGICAL (ZAP-70 AND CD38), AND MOLECULAR (IGHV MUTATION) MARKERS, DISTINGUISHING CLL CASES ACCORDING TO IGHV MUTATIONAL STATUS. CELL ADHESION MOLECULES WERE ENRICHED IN THE SIGNATURE OF UNMUTATED (UM) VERSUS MUTATED (M-) CLL. MOREOVER, IN M-CLL CPG HYPER-METHYLATION IN THREE GENES, INCLUDING SPG20, WAS SIGNIFICANTLY ANTI-CORRELATED WITH THE CORRESPONDING GENE EXPRESSION LEVEL. FINALLY, THE CORRELATION BETWEEN THE METHYLATION PATTERN AND CLINICAL PARAMETERS WAS INVESTIGATED. NOTABLY, OUT OF 42 METHYL-PROBES THAT WERE SIGNIFICANTLY ASSOCIATED WITH PROGRESSION FREE SURVIVAL (PFS), HYPER-METHYLATION OF SPG20 WAS ALSO POSITIVELY ASSOCIATED WITH PFS. THESE DATA SUPPORT THE NOTION THAT EPIGENETIC CHANGES HAVE CLINICAL IMPACT IN CLL AND MAY CONTRIBUTE TO THE IDENTIFICATION OF NOVEL CANDIDATE DISEASE-ASSOCIATED GENES POTENTIALLY USEFUL TO PREDICT THE CLINICAL OUTCOME OF EARLY STAGE CLL PATIENTS. 2014 5 3098 33 GENOMIC DISRUPTION OF THE HISTONE METHYLTRANSFERASE SETD2 IN CHRONIC LYMPHOCYTIC LEUKAEMIA. HISTONE METHYLTRANSFERASES (HMTS) ARE IMPORTANT EPIGENETIC REGULATORS OF GENE TRANSCRIPTION AND ARE DISRUPTED AT THE GENOMIC LEVEL IN A SPECTRUM OF HUMAN TUMOURS INCLUDING HAEMATOLOGICAL MALIGNANCIES. USING HIGH-RESOLUTION SINGLE NUCLEOTIDE POLYMORPHISM (SNP) ARRAYS, WE IDENTIFIED RECURRENT DELETIONS OF THE SETD2 LOCUS IN 3% (8/261) OF CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) PATIENTS. FURTHER VALIDATION IN TWO INDEPENDENT COHORTS SHOWED THAT SETD2 DELETIONS WERE ASSOCIATED WITH LOSS OF TP53, GENOMIC COMPLEXITY AND CHROMOTHRIPSIS. WITH NEXT-GENERATION SEQUENCING WE DETECTED MUTATIONS OF SETD2 IN AN ADDITIONAL 3.8% OF PATIENTS (23/602). IN MOST CASES, SETD2 DELETIONS OR MUTATIONS WERE OFTEN OBSERVED AS A CLONAL EVENT AND ALWAYS AS A MONO-ALLELIC LESION, LEADING TO REDUCED MRNA EXPRESSION IN SETD2-DISRUPTED CASES. PATIENTS WITH SETD2 ABNORMALITIES AND WILD-TYPE TP53 AND ATM FROM FIVE CLINICAL TRIALS EMPLOYING CHEMOTHERAPY OR CHEMO-IMMUNOTHERAPY HAD REDUCED PROGRESSION-FREE AND OVERALL SURVIVAL COMPARED WITH CASES WILD TYPE FOR ALL THREE GENES. CONSISTENT WITH ITS POSTULATED ROLE AS A TUMOUR SUPPRESSOR, OUR DATA HIGHLIGHT SETD2 ABERRATION AS A RECURRENT, EARLY LOSS-OF-FUNCTION EVENT IN CLL PATHOBIOLOGY LINKED TO AGGRESSIVE DISEASE. 2016 6 59 35 A GENOME-WIDE SCREEN IDENTIFIES FREQUENTLY METHYLATED GENES IN HAEMATOLOGICAL AND EPITHELIAL CANCERS. BACKGROUND: GENETIC AS WELL AS EPIGENETIC ALTERATIONS ARE A HALLMARK OF BOTH EPITHELIAL AND HAEMATOLOGICAL MALIGNANCIES. HIGH THROUGHPUT SCREENS ARE REQUIRED TO IDENTIFY EPIGENETIC MARKERS THAT CAN BE USEFUL FOR DIAGNOSTIC AND PROGNOSTIC PURPOSES ACROSS MALIGNANCIES. RESULTS: HERE WE REPORT FOR THE FIRST TIME THE USE OF THE MIRA ASSAY (METHYLATED CPG ISLAND RECOVERY ASSAY) IN COMBINATION WITH GENOME-WIDE CPG ISLAND ARRAYS TO IDENTIFY EPIGENETIC MOLECULAR MARKERS IN CHILDHOOD ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) ON A GENOME-WIDE SCALE. WE IDENTIFIED 30 GENES DEMONSTRATING METHYLATION FREQUENCIES OF > OR =25% IN CHILDHOOD ALL, NINE GENES SHOWED SIGNIFICANTLY DIFFERENT METHYLATION FREQUENCIES IN B VS T-ALL. FOR MAJORITY OF THE GENES EXPRESSION COULD BE RESTORED IN METHYLATED LEUKEMIA LINES AFTER TREATMENT WITH 5-AZADC. FORTY-FOUR PERCENT OF THE GENES REPRESENT TARGETS OF THE POLYCOMB COMPLEX. IN CHRONIC MYELOID LEUKEMIA (CML) TWO OF THE GENES, (TFAP2A AND EBF2), DEMONSTRATED INCREASED METHYLATION IN BLAST CRISIS COMPARED TO CHRONIC PHASE (P < 0.05). FURTHERMORE HYPERMETHYLATION OF AN AUTOPHAGY RELATED GENE ATG16L2 WAS ASSOCIATED WITH POORER PROGNOSIS IN TERMS OF MOLECULAR RESPONSE TO IMATINIB TREATMENT. LASTLY WE DEMONSTRATED THAT TEN OF THESE GENES WERE ALSO FREQUENTLY METHYLATED IN COMMON EPITHELIAL CANCERS. CONCLUSION: IN SUMMARY WE HAVE IDENTIFIED A LARGE NUMBER OF GENES SHOWING FREQUENT METHYLATION IN CHILDHOOD ALL, METHYLATION STATUS OF TWO OF THESE GENES IS ASSOCIATED WITH ADVANCED DISEASE IN CML AND METHYLATION STATUS OF ANOTHER GENE IS ASSOCIATED WITH PROGNOSIS. IN ADDITION A SUBSET OF THESE GENES MAY ACT AS EPIGENETIC MARKERS ACROSS HEMATOLOGICAL MALIGNANCIES AS WELL AS COMMON EPITHELIAL CANCERS. 2010 7 2966 26 GENETIC AND EPIGENETIC PROFILING OF CLL DISEASE PROGRESSION REVEALS LIMITED SOMATIC EVOLUTION AND SUGGESTS A RELATIONSHIP TO MEMORY-CELL DEVELOPMENT. WE EXAMINED GENETIC AND EPIGENETIC CHANGES THAT OCCUR DURING DISEASE PROGRESSION FROM INDOLENT TO AGGRESSIVE FORMS OF CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) USING SERIAL SAMPLES FROM 27 PATIENTS. ANALYSIS OF DNA MUTATIONS GROUPED THE LEUKEMIA CASES INTO THREE CATEGORIES: EVOLVING (26%), EXPANDING (26%) AND STATIC (47%). THUS, APPROXIMATELY THREE-QUARTERS OF THE CLL CASES HAD LITTLE TO NO GENETIC SUBCLONAL EVOLUTION. HOWEVER, WE IDENTIFIED SIGNIFICANT RECURRENT DNA METHYLATION CHANGES DURING PROGRESSION AT 4752 CPGS ENRICHED FOR REGIONS NEAR POLYCOMB 2 REPRESSIVE COMPLEX (PRC2) TARGETS. PROGRESSION-ASSOCIATED CPGS NEAR THE PRC2 TARGETS UNDERGO METHYLATION CHANGES IN THE SAME DIRECTION DURING DISEASE PROGRESSION AS DURING NORMAL DEVELOPMENT FROM NAIVE TO MEMORY B CELLS. OUR STUDY SHOWS THAT CLL PROGRESSION DOES NOT TYPICALLY OCCUR VIA SUBCLONAL EVOLUTION, BUT THAT CERTAIN CPG SITES UNDERGO RECURRENT METHYLATION CHANGES. OUR RESULTS SUGGEST CLL PROGRESSION MAY INVOLVE DEVELOPMENTAL PROCESSES SHARED IN COMMON WITH THE GENERATION OF NORMAL MEMORY B CELLS. 2015 8 3532 33 IMATINIB INDEPENDENT ABERRANT METHYLATION OF NOV/CCN3 IN CHRONIC MYELOGENOUS LEUKEMIA PATIENTS: A MECHANISM UPSTREAM OF BCR-ABL1 FUNCTION? BACKGROUND: THE NOV GENE PRODUCT, CCN3, HAS BEEN REPORTED IN A DIVERSE RANGE OF TUMORS TO SERVE AS A NEGATIVE GROWTH REGULATOR, WHILE ACTING AS A TUMOR SUPPRESSOR IN CHRONIC MYELOGENOUS LEUKEMIA (CML). HOWEVER, THE PRECISE MECHANISM OF ITS SILENCING IN CML IS POORLY UNDERSTOOD. IN THE CURRENT STUDY, WE AIMED TO QUERY IF THE GENE REGULATION OF CCN3 IS MEDIATED BY THE PROMOTER METHYLATION IN THE PATIENTS WITH CML. IN ADDITION, TO CLARIFY WHETHER THE EPIGENETIC SILENCING IS AFFECTED BY BCR-ABL1 INHIBITION, WE ASSESSED THE METHYLATION STATUS IN THE PATIENTS AT DIFFERENT TIME INTERVALS FOLLOWING THE TYROSINE KINASE INHIBITION USING IMATINIB THERAPY, AS THE FIRST-LINE TREATMENT FOR THIS TYPE OF LEUKEMIA. METHODS: TO ADDRESS THIS ISSUE, WE APPLIED BISULFITE-SEQUENCING TECHNIQUE AS A HIGH-RESOLUTION METHOD TO STUDY THE REGULATORY SEGMENT OF THE CCN3 GENE. THE RESULTS WERE ANALYZED IN NEWLY DIAGNOSED CML PATIENTS AS WELL AS FOLLOWING IMATINIB THERAPY. WE ALSO EVALUATED THE CORRELATION OF CCN3 PROMOTER METHYLATION WITH BCR-ABL1 LEVELS. RESULTS: OUR FINDINGS REVEALED THAT THE METHYLATION OCCURS FREQUENTLY IN THE PROMOTER REGION OF CML PATIENTS SHOWING A SIGNIFICANT INCREASE OF THE METHYLATED PERCENTAGE AT THE CPG SITES COMPARED TO NORMAL INDIVIDUALS. INTERESTINGLY, THIS HYPERMETHYLATION WAS INDICATED TO BE INDEPENDENT OF BCR-ABL1 TITERS IN BOTH GROUPS, WHICH MIGHT SUGGEST A MECHANISM BEYOND THE BCR-ABL1 FUNCTION. CONCLUSION: DESPITE SUGGESTING THAT THE CCN3 HYPERMETHYLATION ACTS AS A MOLECULAR MECHANISM INDEPENDENT OF BCR-ABL1 FUNCTION IN CML PATIENTS, THIS SCENARIO REQUIRES FURTHER VALIDATION BY COMPLEMENTARY EXPERIMENTS. IN THE CASE OF ACTING UPSTREAM OF BCR-ABL1 SIGNALING, THE METHYLATION MARKER CAN PROVIDE EARLY DETECTION AND A NOVEL PLATFORM FOR TARGETED EPIGENETIC MODIFIERS FOR EFFICIENT TREATMENT IN IMATINIB RESISTANT PATIENTS. 2019 9 1424 23 DIFFERENTIAL DNA METHYLATION OF GENE PROMOTERS IN SMALL B-CELL LYMPHOMAS. IMPROVED CARE OF PATIENTS WITH SMALL B-CELL LYMPHOMAS (SBCLS) IS LIKELY TO RESULT FROM THE ONGOING DISCOVERY OF MOLECULAR MARKERS THAT BETTER DEFINE THESE MALIGNANT NEOPLASMS. WE IDENTIFIED MULTIPLE GENE LOCI WHOSE DNA METHYLATION PATTERNS DIFFERED BETWEEN 3 TYPES OF SBCL: B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA/SMALL LYMPHOCYTIC LYMPHOMA, MANTLE CELL LYMPHOMA, AND GRADES I AND II FOLLICULAR LYMPHOMA. THIS ANALYSIS WAS PERFORMED USING AN OLIGONUCLEOTIDE MICROARRAY THAT ALLOWED DETERMINATION OF THE DNA METHYLATION STATUS OF 156 LOCI IN 38 GENES. COMBINED BISULFITE RESTRICTION ANALYSIS AND METHYLATION-SPECIFIC POLYMERASE CHAIN REACTION WERE USED TO VALIDATE THE DIFFERENTIAL METHYLATION OF 6 OF THESE GENES. BY USING NON-HODGKIN LYMPHOMA CELL LINES AS MODELS, THESE GENES WERE EXAMINED FURTHER FOR METHYLATION AND GENE EXPRESSION RELATIONSHIPS. THIS STUDY ILLUSTRATES NONRANDOM EPIGENETIC ALTERATIONS IN SBCLS THAT SEEM TO PREFERENTIALLY INVOLVE LYMPHOMAS OF GERMINAL CENTER DERIVATION. 2005 10 15 27 450K-ARRAY ANALYSIS OF CHRONIC LYMPHOCYTIC LEUKEMIA CELLS REVEALS GLOBAL DNA METHYLATION TO BE RELATIVELY STABLE OVER TIME AND SIMILAR IN RESTING AND PROLIFERATIVE COMPARTMENTS. IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), THE MICROENVIRONMENT INFLUENCES GENE EXPRESSION PATTERNS; HOWEVER, KNOWLEDGE IS LIMITED REGARDING THE EXTENT TO WHICH METHYLATION CHANGES WITH TIME AND EXPOSURE TO SPECIFIC MICROENVIRONMENTS. USING HIGH-RESOLUTION 450K ARRAYS, WE PROVIDE THE MOST COMPREHENSIVE DNA METHYLATION STUDY OF CLL TO DATE, ANALYZING PAIRED DIAGNOSTIC/FOLLOW-UP SAMPLES FROM IGHV-MUTATED/UNTREATED AND IGHV-UNMUTATED/TREATED PATIENTS (N=36) AND PATIENT-MATCHED PERIPHERAL BLOOD AND LYMPH NODE SAMPLES (N=20). ON AN UNPRECEDENTED SCALE, WE REVEALED 2239 DIFFERENTIALLY METHYLATED CPG SITES BETWEEN IGHV-MUTATED AND UNMUTATED PATIENTS, WITH THE MAJORITY OF SITES POSITIONED OUTSIDE ANNOTATED CPG ISLANDS. INTRIGUINGLY, CLL PROGNOSTIC GENES (FOR EXAMPLE, CLLU1, LPL, ZAP70 AND NOTCH1), EPIGENETIC REGULATOR (FOR EXAMPLE, HDAC9, HDAC4 AND DNMT3B), B-CELL SIGNALING (FOR EXAMPLE, IBTK) AND NUMEROUS TGF-BETA AND NF-KAPPAB/TNF PATHWAY GENES WERE ALTERNATIVELY METHYLATED BETWEEN SUBGROUPS. CONTRARY, DNA METHYLATION OVER TIME WAS DEEMED RATHER STABLE WITH FEW RECURRENT CHANGES NOTED WITHIN SUBGROUPS. ALTHOUGH A LARGER NUMBER OF NON-RECURRENT CHANGES WERE IDENTIFIED AMONG IGHV-UNMUTATED RELATIVE TO MUTATED CASES OVER TIME, THESE EQUATED TO A LOW GLOBAL CHANGE. SIMILARLY, FEW CHANGES WERE IDENTIFIED BETWEEN COMPARTMENT CASES. ALTOGETHER, WE REVEAL CLL SUBGROUPS TO DISPLAY UNIQUE METHYLATION PROFILES AND UNVEIL METHYLATION AS RELATIVELY STABLE OVER TIME AND SIMILAR WITHIN DIFFERENT CLL COMPARTMENTS, IMPLYING ABERRANT METHYLATION AS AN EARLY LEUKEMOGENIC EVENT. 2013 11 4694 26 NEXT-GENERATION SEQUENCING IDENTIFIES MAJOR DNA METHYLATION CHANGES DURING PROGRESSION OF PH+ CHRONIC MYELOID LEUKEMIA. LITTLE IS KNOWN ABOUT THE IMPACT OF DNA METHYLATION ON THE EVOLUTION/PROGRESSION OF PH+ CHRONIC MYELOID LEUKEMIA (CML). WE INVESTIGATED THE METHYLOME OF CML PATIENTS IN CHRONIC PHASE (CP-CML), ACCELERATED PHASE (AP-CML) AND BLAST CRISIS (BC-CML) AS WELL AS IN CONTROLS BY REDUCED REPRESENTATION BISULFITE SEQUENCING. ALTHOUGH ONLY ~600 DIFFERENTIALLY METHYLATED CPG SITES WERE IDENTIFIED IN SAMPLES OBTAINED FROM CP-CML PATIENTS COMPARED WITH CONTROLS, ~6500 DIFFERENTIALLY METHYLATED CPG SITES WERE FOUND IN SAMPLES FROM BC-CML PATIENTS. IN THE MAJORITY OF AFFECTED CPG SITES, METHYLATION WAS INCREASED. IN CP-CML PATIENTS WHO PROGRESSED TO AP-CML/BC-CML, WE IDENTIFIED UP TO 897 GENES THAT WERE METHYLATED AT THE TIME OF PROGRESSION BUT NOT AT THE TIME OF DIAGNOSIS. USING RNA-SEQUENCING, WE OBSERVED DOWNREGULATED EXPRESSION OF MANY OF THESE GENES IN BC-CML COMPARED WITH CP-CML SAMPLES. SEVERAL OF THEM ARE WELL-KNOWN TUMOR-SUPPRESSOR GENES OR REGULATORS OF CELL PROLIFERATION, AND GENE RE-EXPRESSION WAS OBSERVED BY THE USE OF EPIGENETIC ACTIVE DRUGS. TOGETHER, OUR RESULTS DEMONSTRATE THAT CPG SITE METHYLATION CLEARLY INCREASES DURING CML PROGRESSION AND THAT IT MAY PROVIDE A USEFUL BASIS FOR REVEALING NEW TARGETS OF THERAPY IN ADVANCED CML. 2016 12 4221 32 METHYLATION AND SILENCING OF PROTEIN TYROSINE PHOSPHATASE RECEPTOR TYPE O IN CHRONIC LYMPHOCYTIC LEUKEMIA. PURPOSE: PREVIOUS STUDIES IN OUR LABORATORY HAVE SHOWN THE PROGRESSIVE METHYLATION AND SUPPRESSION OF THE GENE ENCODING PROTEIN TYROSINE PHOSPHATASE, PTPRO, IN THE LIVERS OF RATS FED A METHYL-DEFICIENT DIET THAT INDUCES HEPATOCARCINOGENESIS. SUBSEQUENTLY, WE OBSERVED THE METHYLATION OF PTPRO IN PRIMARY HUMAN LUNG TUMORS AND ALSO SHOWED ITS POTENTIAL TUMOR SUPPRESSOR CHARACTERISTICS. THE PRESENT STUDY WAS UNDERTAKEN TO INVESTIGATE WHETHER THE TRUNCATED FORM OF PTPRO (PTPROT), SPECIFICALLY EXPRESSED IN NAIVE B LYMPHOCYTES, WAS ALSO METHYLATED AND SUPPRESSED IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), A DISEASE GENERALLY AFFECTING B LYMPHOCYTES. EXPERIMENTAL DESIGN AND RESULTS: INITIAL SCREENING SHOWED THAT 60% OF THE 52 CLL SAMPLES ANALYZED USING METHYLATION-SPECIFIC PCR ASSAY WERE METHYLATED COMPARED WITH B LYMPHOCYTES FROM NORMAL INDIVIDUALS, WHICH WERE NOT METHYLATED. THE EXPRESSION OF PTPROT, AS MEASURED BY SEMIQUANTITATIVE REVERSE TRANSCRIPTION-PCR, INVERSELY CORRELATED WITH METHYLATION IN THE FEW SAMPLES TESTED. ANALYSIS OF ADDITIONAL SAMPLES (N = 50) BY COMBINED BISULFITE RESTRICTION ANALYSIS SHOWED THAT THE PTPRO CPG ISLAND WAS METHYLATED IN 82% OF PATIENTS WITH CLL COMPARED WITH B LYMPHOCYTES FROM NORMAL INDIVIDUALS. FURTHERMORE, OVERALL EXPRESSION OF PTPRO WAS REDUCED IN CLL RELATIVE TO NORMAL LYMPHOCYTES. THE PTPRO GENE WAS ALSO SUPPRESSED BY METHYLATION IN THE CLL CELL LINE WAC3CD5, WHERE IT COULD BE REACTIVATED UPON TREATMENT WITH THE DNA HYPOMETHYLATING AGENT 5-AZAC. ECTOPIC EXPRESSION OF PTPROT IN A NONEXPRESSING CELL LINE INCREASED GROWTH INHIBITION WITH FLUDARABINE TREATMENT, A THERAPY COMMONLY USED FOR CLL. CONCLUSION: THIS STUDY REVEALS THE POTENTIAL ROLE OF PTPRO METHYLATION AND SILENCING IN CLL TUMORIGENESIS AND ALSO PROVIDES A NOVEL MOLECULAR TARGET IN THE EPIGENETIC THERAPY. 2007 13 1561 39 DNA METHYLATION OF CHRONIC LYMPHOCYTIC LEUKEMIA WITH DIFFERENTIAL RESPONSE TO CHEMOTHERAPY. ACQUIRED RESISTANCE TO CHEMOTHERAPY IS AN IMPORTANT CLINICAL PROBLEM AND CAN ALSO OCCUR WITHOUT DETECTABLE CYTOGENETIC ABERRATIONS OR GENE MUTATIONS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS MOLECULARLY WELL CHARACTERIZED AND HAS BEEN ELEMENTAL FOR ESTABLISHING CENTRAL PARADIGMS IN ONCOLOGY. THIS PROMPTED US TO CHECK WHETHER SPECIFIC EPIGENETIC CHANGES AT THE LEVEL OF DNA METHYLATION MIGHT UNDERLIE DEVELOPMENT OF TREATMENT RESISTANCE. WE USED ILLUMINA INFINIUM HUMANMETHYLATION450 BEADCHIPS TO OBTAIN DNA METHYLATION PROFILES OF 71 CLL PATIENTS WITH DIFFERENTIAL RESPONSES. THIRTY-SIX PATIENTS WERE CATEGORIZED AS RELAPSED/REFRACTORY AFTER TREATMENT WITH FLUDARABINE OR BENDAMUSTINE AND 21 OF THEM HAD GENETIC ABERRATIONS OF TP53. THE OTHER 35 PATIENTS WERE UNTREATED AT THE TIME OF SAMPLING AND 15 OF THEM HAD GENETIC ABERRATION OF TP53. ALTHOUGH WE COULD NOT CORRELATE CHEMORESISTANCE WITH EPIGENETIC CHANGES, THE PATIENTS WERE COMPREHENSIVELY CHARACTERIZED REGARDING RELEVANT PROGNOSTIC AND MOLECULAR MARKERS (E.G. IGHV MUTATION STATUS, CHROMOSOME ABERRATIONS, TP53 MUTATION STATUS, CLINICAL PARAMETERS), WHICH MAKES OUR DATASET A UNIQUE AND VALUABLE RESOURCE THAT CAN BE USED BY RESEARCHERS TO TEST ALTERNATIVE HYPOTHESES. 2020 14 1682 28 DRUG-MICROENVIRONMENT PERTURBATIONS REVEAL RESISTANCE MECHANISMS AND PROGNOSTIC SUBGROUPS IN CLL. THE TUMOUR MICROENVIRONMENT AND GENETIC ALTERATIONS COLLECTIVELY INFLUENCE DRUG EFFICACY IN CANCER, BUT CURRENT EVIDENCE IS LIMITED AND SYSTEMATIC ANALYSES ARE LACKING. USING CHRONIC LYMPHOCYTIC LEUKAEMIA (CLL) AS A MODEL DISEASE, WE INVESTIGATED THE INFLUENCE OF 17 MICROENVIRONMENTAL STIMULI ON 12 DRUGS IN 192 GENETICALLY CHARACTERISED PATIENT SAMPLES. BASED ON MICROENVIRONMENTAL RESPONSE, WE IDENTIFIED FOUR SUBGROUPS WITH DISTINCT CLINICAL OUTCOMES BEYOND KNOWN PROGNOSTIC MARKERS. RESPONSE TO MULTIPLE MICROENVIRONMENTAL STIMULI WAS AMPLIFIED IN TRISOMY 12 SAMPLES. TRISOMY 12 WAS ASSOCIATED WITH A DISTINCT EPIGENETIC SIGNATURE. BROMODOMAIN INHIBITION REVERSED THIS EPIGENETIC PROFILE AND COULD BE USED TO TARGET MICROENVIRONMENTAL SIGNALLING IN TRISOMY 12 CLL. WE QUANTIFIED THE IMPACT OF MICROENVIRONMENTAL STIMULI ON DRUG RESPONSE AND THEIR DEPENDENCE ON GENETIC ALTERATIONS, IDENTIFYING INTERLEUKIN 4 (IL4) AND TOLL-LIKE RECEPTOR (TLR) STIMULATION AS THE STRONGEST ACTUATORS OF DRUG RESISTANCE. IL4 AND TLR SIGNALLING ACTIVITY WAS INCREASED IN CLL-INFILTRATED LYMPH NODES COMPARED WITH HEALTHY SAMPLES. HIGH IL4 ACTIVITY CORRELATED WITH FASTER DISEASE PROGRESSION. THE PUBLICLY AVAILABLE DATASET CAN FACILITATE THE INVESTIGATION OF CELL-EXTRINSIC MECHANISMS OF DRUG RESISTANCE AND DISEASE PROGRESSION. 2022 15 139 34 ABERRANT DNA METHYLATION IS ASSOCIATED WITH DISEASE PROGRESSION, RESISTANCE TO IMATINIB AND SHORTENED SURVIVAL IN CHRONIC MYELOGENOUS LEUKEMIA. THE EPIGENETIC IMPACT OF DNA METHYLATION IN CHRONIC MYELOGENOUS LEUKEMIA (CML) IS NOT COMPLETELY UNDERSTOOD. TO ELUCIDATE ITS ROLE WE ANALYZED 120 PATIENTS WITH CML FOR METHYLATION OF PROMOTER-ASSOCIATED CPG ISLANDS OF 10 GENES. FIVE GENES WERE IDENTIFIED BY DNA METHYLATION SCREENING IN THE K562 CELL LINE AND 3 GENES IN PATIENTS WITH MYELOPROLIFERATIVE NEOPLASMS. THE CDKN2B GENE WAS SELECTED FOR ITS FREQUENT METHYLATION IN MYELOID MALIGNANCIES AND ABL1 AS THE TARGET OF BCR-ABL TRANSLOCATION. THIRTY PATIENTS WERE IMATINIB-NAIVE (MOSTLY TREATED BY INTERFERON-ALPHA BEFORE THE IMATINIB ERA), 30 WERE IMATINIB-RESPONSIVE, 50 WERE IMATINIB-RESISTANT, AND 10 WERE IMATINIB-INTOLERANT. WE QUANTIFIED DNA METHYLATION BY BISULFITE PYROSEQUENCING. THE AVERAGE NUMBER OF METHYLATED GENES WAS 4.5 PER PATIENT IN THE CHRONIC PHASE, INCREASING SIGNIFICANTLY TO 6.2 IN THE ACCELERATED AND 6.4 IN THE BLASTIC PHASE. HIGHER NUMBERS OF METHYLATED GENES WERE ALSO OBSERVED IN PATIENTS RESISTANT OR INTOLERANT TO IMATINIB. THESE PATIENTS ALSO SHOWED ALMOST EXCLUSIVE METHYLATION OF A PUTATIVE TRANSPORTER OSCP1. ABNORMAL METHYLATION OF A SRC SUPPRESSOR GENE PDLIM4 WAS ASSOCIATED WITH SHORTENED SURVIVAL INDEPENDENTLY OF CML STAGE AND IMATINIB RESPONSIVENESS. WE CONCLUDE THAT ABERRANT DNA METHYLATION IS ASSOCIATED WITH CML PROGRESSION AND THAT DNA METHYLATION COULD BE A MARKER ASSOCIATED WITH IMATINIB RESISTANCE. FINALLY, DNA METHYLATION OF PDLIM4 MAY HELP IDENTIFY A SUBSET OF CML PATIENTS THAT WOULD BENEFIT FROM TREATMENT WITH SRC/ABL INHIBITORS. 2011 16 5275 32 PROMOTER METHYLATION OF THE BONE MORPHOGENETIC PROTEIN-6 GENE IN ASSOCIATION WITH ADULT T-CELL LEUKEMIA. BONE MORPHOGENETIC PROTEINS (BMP), BELONGING TO THE TRANSFORMING GROWTH FACTOR-BETA SUPERFAMILY, ARE MULTIFUNCTIONAL REGULATORS OF CELL PROLIFERATION, DIFFERENTIATION AND APOPTOSIS IN VARIOUS TYPES OF MALIGNANT CELLS. IN THIS STUDY, WE INVESTIGATED BMP-6 PROMOTER METHYLATION IN PATIENTS WITH VARIOUS TYPES OF LEUKEMIAS. THE BMP-6 METHYLATION WAS FOUND PREFERENTIALLY IN ADULT T-CELL LEUKEMIA (ATL) (49 OF 60, 82%) COMPARED WITH OTHER TYPES OF LEUKEMIAS STUDIED INCLUDING ACUTE MYELOID LEUKEMIA (3 OF 67, 5%), ACUTE LYMPHOBLASTIC LEUKEMIA (6 OF 38, 16%) AND CHRONIC LYMPHOCYTIC LEUKEMIA (1 OF 21, 5%). AMONG SUBTYPES OF ATL, THE BMP-6 GENE WAS MORE FREQUENTLY METHYLATED IN AGGRESSIVE ATL FORMS OF ACUTE (96%) AND LYMPHOMA (94%) TYPES THAN LESS MALIGNANT CHRONIC ATL (44%) AND SMOLDERING ATL (20%). WE ALSO ANALYZED THE METHYLATION STATUS OF PERIPHERAL BLOOD MONONUCLEAR CELLS FROM HEALTHY DONORS AND NONMALIGNANT LYMPH NODES WITH REACTIVE LYMPHADENOPATHY, NONE OF WHICH SHOWED DETECTABLE BMP-6 METHYLATION IN THIS STUDY. THE BMP-6 METHYALTION WAS CORRELATED WITH DECREASED MRNA TRANSCRIPT AND PROTEIN EXPRESSION. EXPRESSION OF BMP-6 WAS RESTORED BY THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE, SUGGESTING THAT METHYLATION WAS ASSOCIATED WITH THE TRANSCRIPTIONAL SILENCING. SERIAL ANALYSIS DEMONSTRATED AN INCREASING METHYLATION OF CPG SITES IN THE BMP-6 PROMOTER AND THE RESULTANT SUPPRESSION OF BMP-6 EXPRESSION AS ATL PROGRESSED. THESE FINDINGS SUGGESTED THAT BMP-6 PROMOTER METHYLATION IS LIKELY TO BE A COMMON EPIGENETIC EVENT AT LATER STAGES OF ATL AND THAT THE METHYLATION PROFILES MAY BE USEFUL FOR THE STAGING OF ATL AS WELL AS FOR EVALUATION OF THE INDIVIDUAL RISK OF DEVELOPING THE DISEASE. 2008 17 2689 24 EVOLUTION OF DNA METHYLATION IS LINKED TO GENETIC ABERRATIONS IN CHRONIC LYMPHOCYTIC LEUKEMIA. ALTHOUGH CLONAL SELECTION BY GENETIC DRIVER ABERRATIONS IN CANCER IS WELL DOCUMENTED, THE ABILITY OF EPIGENETIC ALTERATIONS TO PROMOTE TUMOR EVOLUTION IS UNDEFINED. WE USED 450K ARRAYS AND NEXT-GENERATION SEQUENCING TO EVALUATE INTRATUMOR HETEROGENEITY AND EVOLUTION OF DNA METHYLATION AND GENETIC ABERRATIONS IN CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). CLL CASES EXHIBIT VAST INTERPATIENT DIFFERENCES IN INTRATUMOR METHYLATION HETEROGENEITY, WITH GENETICALLY CLONAL CASES MAINTAINING LOW METHYLATION HETEROGENEITY AND UP TO 10% OF TOTAL CPGS IN A MONOALLELICALLY METHYLATED STATE. INCREASING METHYLATION HETEROGENEITY CORRELATES WITH ADVANCED GENETIC SUBCLONAL COMPLEXITY. SELECTION OF NOVEL DNA METHYLATION PATTERNS IS OBSERVED ONLY IN CASES THAT UNDERGO GENETIC EVOLUTION, AND INDEPENDENT GENETIC EVOLUTION IS UNCOMMON AND IS RESTRICTED TO LOW-RISK ALTERATIONS. THESE RESULTS REVEAL THAT ALTHOUGH EVOLUTION OF DNA METHYLATION OCCURS IN HIGH-RISK, CLINICALLY PROGRESSIVE CASES, POSITIVE SELECTION OF NOVEL METHYLATION PATTERNS ENTAILS COEVOLUTION OF GENETIC ALTERATION(S) IN CLL. 2014 18 3896 27 LARGE-SCALE ANALYSIS OF DNA METHYLATION IN CHRONIC LYMPHOCYTIC LEUKEMIA. AIMS: B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A HETEROGENEOUS MALIGNANCY THAT CLINICALLY RANGES FROM INDOLENT TO RAPIDLY PROGRESSIVE. CLL, LIKE OTHER CANCERS, CAN BE AFFECTED BY EPIGENETIC ALTERATIONS. MATERIALS & METHODS: A MICROARRAY DISCOVERY-BASED STUDY WAS INITIATED TO DETERMINE DNA METHYLATION IN CLL CASES WITH A RANGE OF CD38 EXPRESSION (1-92%). RESULTS: MANY LOCI WERE EITHER METHYLATED OR UNMETHYLATED ACROSS ALL CD38 LEVELS, BUT DIFFERENTIAL METHYLATION WAS ALSO OBSERVED FOR SOME GENES. GENOMIC SEQUENCING OF DLEU7 CONFIRMED EXTENSIVE CYTOSINE METHYLATION PREFERENTIALLY IN PATIENT SAMPLES WITH LOW CD38 EXPRESSION, WHEREAS NRP2, SFRP2 AND ADAM12 WERE MORE COMMONLY METHYLATED IN THOSE WITH HIGH CD38 EXPRESSION. CONCLUSION: THIS STUDY DEMONSTRATES THAT CLL IS AFFECTED BY CPG ISLAND METHYLATION IN SOME GENES THAT SEGREGATE WITH CD38 EXPRESSION LEVELS, WHILE MOST OTHERS SHOW SIMILAR METHYLATION PATTERNS ACROSS ALL LEVELS. THE CPG ISLAND METHYLATION IN CERTAIN FUNCTIONAL GENE GROUPS AND PATHWAY-ASSOCIATED GENES THAT ARE KNOWN TO BE DEREGULATED IN CLL PROVIDES ADDITIONAL INSIGHTS INTO THE CLL METHYLOME AND EPIGENETIC CONTRIBUTION TO CELLULAR DYSFUNCTION. IT WILL NOW BE USEFUL TO INVESTIGATE THE EFFECTIVENESS OF EPIGENETIC THERAPEUTIC REVERSAL OF THESE ALTERATIONS TO DEVELOP EFFECTIVE TREATMENTS FOR THE DISEASE. 2009 19 5210 24 PRENEOPLASTIC ALTERATIONS DEFINE CLL DNA METHYLOME AND PERSIST THROUGH DISEASE PROGRESSION AND THERAPY. MOST HUMAN CANCERS CONVERGE TO A DEREGULATED METHYLOME WITH REDUCED GLOBAL LEVELS AND ELEVATED METHYLATION AT SELECT CPG ISLANDS. TO INVESTIGATE THE EMERGENCE AND DYNAMICS OF THE CANCER METHYLOME, WE CHARACTERIZED GENOME-WIDE DNA METHYLATION IN PRE-NEOPLASTIC MONOCLONAL B CELL LYMPHOCYTOSIS (MBL) AND CHRONIC LYMPHOCYTIC LEUKEMIA (CLL), INCLUDING SERIAL SAMPLES COLLECTED ACROSS DISEASE COURSE. WE DETECTED THE ABERRANT TUMOR-ASSOCIATED METHYLATION LANDSCAPE AT CLL DIAGNOSIS AND FOUND NO SIGNIFICANTLY DIFFERENTIALLY METHYLATED REGIONS IN THE HIGH-COUNT MBL-TO-CLL TRANSITION. PATIENT METHYLOMES SHOWED REMARKABLE STABILITY WITH NATURAL DISEASE AND POST-THERAPY PROGRESSION. SINGLE CLL CELLS WERE CONSISTENTLY ABERRANTLY METHYLATED, INDICATING A HOMOGENEOUS TRANSITION TO THE ALTERED EPIGENETIC STATE, AND A DISTINCT EXPRESSION PROFILE TOGETHER WITH MBL CELLS COMPARED TO NORMAL B CELLS. OUR LONGITUDINAL ANALYSIS REVEALS THE CANCER METHYLOME TO EMERGE EARLY, WHICH MAY PROVIDE A PLATFORM FOR SUBSEQUENT GENETICALLY-DRIVEN GROWTH DYNAMICS AND TOGETHER WITH ITS PERSISTENT PRESENCE SUGGESTS A CENTRAL ROLE IN THE NORMAL-TO-CANCER TRANSITION. 2021 20 6488 33 TP53 R72P POLYMORPHISM MODULATES DNA METHYLATION IN HEPATOCELLULAR CARCINOMA. BACKGROUND: HEPATOCELLULAR CARCINOMA (HCC) IS CHARACTERIZED BY WIDESPREAD EPIDEMIOLOGICAL AND MOLECULAR HETEROGENEITY. PREVIOUS WORK SHOWED THAT IN THE WESTERN PART OF NORTH AFRICA, A REGION OF LOW INCIDENCE OF HCC, MUTATIONS ARE SCARCE FOR THIS TUMOR TYPE. AS EPIGENETIC CHANGES ARE CONSIDERED POSSIBLE SURROGATES TO MUTATIONS IN HUMAN CANCERS, WE DECIDED, THUS, TO CHARACTERIZE DNA METHYLATION IN HCC FROM NORTH-AFRICAN PATIENTS. METHODS: A SET OF 11 LOCI WAS INVESTIGATED IN A SERIES OF 45 TUMOR SPECIMENS USING METHYLATION-SPECIFIC AND COMBINED-BISULFITE RESTRICTION ASSAY PCR. RESULTS OBTAINED ON CLINICAL SAMPLES WERE SUBSEQUENTLY VALIDATED IN LIVER CANCER CELL LINES. RESULTS: DNA METHYLATION AT TUMOR SUPPRESSOR LOCI IS SIGNIFICANTLY HIGHER IN SAMPLES DISPLAYING CHROMOSOME INSTABILITY. MORE IMPORTANTLY, DNA METHYLATION WAS SIGNIFICANTLY HIGHER IN ARG/ARG WHEN COMPARED TO PRO/PRO GENOTYPE CARRIERS AT CODON 72 RS1042522 OF TP53 (65% VS 20% METHYLATED LOCI, P = 0.0006), A POLYMORPHISM ALREADY KNOWN TO AFFECT SOMATIC MUTATION RATE IN HUMAN CARCINOMAS. IN VITRO EXPERIMENTS IN CELL LINES INDICATED THAT ENZYMES CONTROLLING DNA METHYLATION WERE DIFFERENTIALLY REGULATED BY CODON 72 ARG OR PRO ISOFORMS OF P53. FURTHERMORE, THE ARG72-CARRYING VERSION OF P53 WAS SHOWN TO RE-METHYLATE DNA MORE RAPIDLY THAN THE PRO-HARBORING ISOFORM. FINALLY, PRO-CARRYING CELL LINES WERE SHOWN TO BE SIGNIFICANTLY MORE RESISTANT TO DECITABINE TREATMENT (TWO-FOLD, P = 0.005). CONCLUSIONS: OUR DATA SUGGEST THAT ARG72PRO POLYMORPHISM IN A WT P53 CONTEXT MAY ACT AS A PRIMARY DRIVER OF EPIGENETIC CHANGES IN HCC. IT SUGGESTS, IN ADDITION, THAT RS1042522 GENOTYPE MAY PREDICT SENSITIVITY TO EPIGENETIC-TARGETED THERAPY. THIS MODEL OF LIVER TUMORIGENESIS THAT ASSOCIATES LOW PENETRANCE GENETIC PREDISPOSITION TO EPIGENETIC CHANGES EMERGES FROM A REGION OF LOW HCC INCIDENCE AND IT MAY, THEREFORE, APPLY ESSENTIALLY TO POPULATION LIVING IN SIMILAR AREAS. SURVEYS ON POPULATIONS SUBMITTED TO HIGHLY MUTAGENIC CONDITIONS AS PERINATALLY-ACQUIRED CHRONIC HEPATITIS B OR AFLATOXIN B1 EXPOSURE REMAINED TO BE CONDUCTED TO VALIDATE OUR OBSERVATIONS AS A GENERAL MODEL. 2015