1 2996 79 GENETIC PROFILE AND MICROSATELLITE INSTABILITY IN A CASE OF SECONDARY ESOPHAGEAL SQUAMOUS CELL CARCINOMA 12 YEARS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION FOR APLASTIC ANEMIA. WE REPORT ON A 16-YEAR-OLD JAPANESE BOY IN WHOM AN ESOPHAGEAL SQUAMOUS CELL CARCINOMA (ESCC) DEVELOPED 12 YEARS AFTER ALLOGENEIC HEMATOPOIETIC STEM CELL TRANSPLANTATION WAS PERFORMED FOR APLASTIC ANEMIA. A HIGH FREQUENCY OF MICROSATELLITE INSTABILITY WAS DETECTED IN SAMPLES OF ESCC. MOREOVER, THE DETECTION OF PATHOGENIC VARIANTS, INCLUDING SINGLE NUCLEOTIDE SUBSTITUTION OF TP53 (C.346C>T) AND BRCA2 (C.6952C>T) AND SPLICING OF KDM6A (C.1194+2T>G), SUGGEST THAT THE DEVELOPMENT OF ESCC IN THE PATIENT WAS TRIGGERED BY IMPAIRMENT OF CHECKPOINT AND REPAIR FOR DNA DAMAGE AND EPIGENETIC MODIFICATION THROUGH ACCUMULATION OF GENE MUTATIONS INDUCED BY CHRONIC GRAFT-VERSUS-HOST DISEASE AND PROLONGED ADMINISTRATION OF TACROLIMUS. 2020 2 4549 21 MUTATION ANALYSIS OF THERAPY-RELATED MYELOID NEOPLASMS. WE ANALYZED THE GENETIC MUTATION STATUS OF 13 PATIENTS WITH THERAPY-RELATED MYELOID NEOPLASMS (T-MN). CONSISTENT WITH PREVIOUS REPORTS, T-MN CELLS PREFERENTIALLY ACQUIRED MUTATIONS IN TP53 AND EPIGENETIC MODIFYING GENES, INSTEAD OF MUTATIONS IN TYROSINE KINASE AND SPLICEOSOME GENES. FURTHERMORE, WE COMPARED THE MUTATION STATUS OF THREE T-MN CELLS WITH EACH OF THE INITIAL LYMPHOID MALIGNANT CELLS, AND IDENTIFIED COMMON MUTATIONS AMONG T-MN AND THE INITIAL MALIGNANT CELLS IN TWO PATIENTS. IN A PATIENT WHO DEVELOPED CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML) AFTER FOLLICULAR LYMPHOMA (FL), TET2 MUTATION WAS IDENTIFIED IN BOTH CMML AND FL CELLS. NOTABLY, THE TET2 MUTATION WAS ALSO IDENTIFIED IN PERIPHERAL BLOOD CELLS IN THE DISEASE-FREE PERIOD WITH THE SAME ALLELIC FREQUENCY AS CMML AND FL CELLS, BUT NOT IN A GERM-LINE CONTROL, INDICATING THAT THE TET2 MUTATION OCCURRED SOMATICALLY IN THE INITIATING CLONE FOR BOTH MALIGNANT CELLS. ON THE OTHER HAND, A GERM-LINE MYB MUTATION WAS IDENTIFIED IN A PATIENT WHO DEVELOPED MYELODYSPLASTIC SYNDROMES (MDS) AFTER FL. THESE RESULTS SUGGEST THAT GERM-LINE DEPOSITION AND CLONAL HEMATOPOIESIS ARE CLOSELY ASSOCIATED WITH T-MN SUSCEPTIBILITY; HOWEVER, FURTHER ANALYSIS IS NECESSARY TO CLARIFY THE MECHANISM REQUIRED TO PROVIDE THE INITIATING CLONE WITH LINEAGE COMMITMENT AND CLONAL EXPANSION. 2018 3 3317 21 HISTOLOGICAL TRANSFORMATION TO SIGNET-RING CELL CARCINOMA IN A PATIENT WITH CLINICALLY AGGRESSIVE POORLY DIFFERENTIATED ADENOCARCINOMA OF THE ASCENDING COLON AFTER RESPONSE TO CHEMOTHERAPY PLUS CETUXIMAB: A CASE REPORT. BACKGROUND: ALTERATION OF CHEMOSENSITIVITY OR TUMOR AGGRESSIVENESS IN RESPONSE TO CHEMOTHERAPY HAS BEEN REPORTED, AND LIQUID BIOPSY ASSESSMENT DURING CHEMOTHERAPY FOR COLORECTAL CANCERS HAS CONFIRMED THE ACQUISITION OF MUTATIONS IN VARIOUS ONCOGENES. HOWEVER, THE OCCURRENCE OF HISTOLOGICAL TRANSFORMATION SEEMS TO BE EXTREMELY RARE IN COLORECTAL CANCERS, AND THE FEW EXISTING CASE REPORTS OF THIS TRANSFORMATION ARE FROM LUNG CANCER AND BREAST CANCER. IN THIS REPORT, WE DESCRIBE THE HISTOLOGICAL TRANSFORMATION OF CLINICALLY AGGRESSIVE SCIRRHOUS-TYPE POORLY DIFFERENTIATED ADENOCARCINOMA OF THE ASCENDING COLON TO SIGNET-RING CELL CARCINOMA IN ALMOST ALL RECURRENT TUMORS THAT WERE CONFIRMED BY AUTOPSY AFTER RESPONSE TO CHEMOTHERAPY PLUS CETUXIMAB. CASE PRESENTATION: A 59-YEAR-OLD WOMAN VISITED OUR HOSPITAL WITH WHOLE ABDOMINAL PAIN AND BODY WEIGHT LOSS AND WAS DIAGNOSED WITH SCIRRHOUS-TYPE POORLY DIFFERENTIATED ADENOCARCINOMA OF THE ASCENDING COLON WITH AGGRESSIVE LYMPH NODE METASTASES. THE INTRINSIC CHEMOSENSITIVITY OF THE TUMORS WAS EVIDENT UPON INITIATION OF MFOLFOX6 PLUS CETUXIMAB THERAPY, AND RIGHT HEMICOLECTOMY WAS PERFORMED, AND THE TUMOR OBVIOUSLY REMAINED IN THE PERIPANCREATIC AREA, PARAAORTIC REGION, OR OTHER RETROPERITONEAL AREAS. THE ASCENDING COLON TUMORS MAINLY CONSISTED OF POORLY DIFFERENTIATED ADENOCARCINOMA AND WERE NOT ASSOCIATED WITH SIGNET-RING CELL COMPONENTS EXCEPT FOR MINUTE CLUSTERS IN A FEW LYMPHATIC EMBOLI IN THE MAIN TUMOR. CHEMOTHERAPY WAS CONTINUED, AND METASTASES WERE ELIMINATED AT 8 MONTHS AFTER THE OPERATION; THIS RESPONSE WAS MAINTAINED FOR AN ADDITIONAL 4 MONTHS. DISCONTINUATION OF CHEMOTHERAPY PLUS CETUXIMAB RESULTED IN IMMEDIATE TUMOR RECURRENCE AND RAPID EXPANSION, AND THE PATIENT DIED OF THE RECURRENT TUMOR 1 YEAR AND 2 MONTHS AFTER THE OPERATION. AUTOPSY SPECIMENS REVEALED THAT ALMOST ALL OF THE RECURRENT TUMORS EXHIBITED TRANSFORMATION AND CONSISTED OF SIGNET-RING CELL HISTOLOGY. CONCLUSION: THIS CASE MIGHT SUGGEST THAT VARIOUS ONCOGENE MUTATIONS OR EPIGENETIC CHANGES RESULTING FROM CHEMOTHERAPY, ESPECIALLY REGIMENS THAT INCLUDE CETUXIMAB, CONTRIBUTE TO THE TRANSFORMATION OF NON-SIGNET-RING CELL COLORECTAL CARCINOMA TO SIGNET-RING CELL CARCINOMA HISTOLOGY AND CAN PROMOTE THE AGGRESSIVE CLINICAL PROGRESSION CHARACTERISTIC OF SIGNET-RING CELL CARCINOMA. 2023 4 5785 20 SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 RAT LIVER EPITHELIAL CELLS. SEVERAL STUDIES HAVE SHOWN THAT CULTURED RAT LIVER EPITHELIAL CELLS TRANSFORM SPONTANEOUSLY AFTER CHRONIC MAINTENANCE IN A CONFLUENT STATE IN VITRO. IN THE PRESENT STUDY, MULTIPLE INDEPENDENT LINEAGES OF LOW-PASSAGE WB-F344 RAT LIVER EPITHELIAL STEM-LIKE CELLS WERE INITIATED AND SUBJECTED IN PARALLEL TO SELECTION FOR SPONTANEOUS TRANSFORMATION TO DETERMINE WHETHER SPONTANEOUS ACQUISITION OF TUMORIGENICITY WAS THE RESULT OF EVENTS (GENETIC OR EPIGENETIC) THAT OCCURRED INDEPENDENTLY AND STOCHASTICALLY, OR REFLECTED THE EXPRESSION OF A PRE-EXISTING ALTERATION WITHIN THE PARENTAL WB-F344 CELL LINE. TEMPORAL ANALYSIS OF THE SPONTANEOUS ACQUISITION OF TUMORIGENICITY BY WB-F344 CELLS DEMONSTRATED LINEAGE-SPECIFIC DIFFERENCES IN THE TIME OF FIRST EXPRESSION OF THE TUMORIGENIC PHENOTYPE, FREQUENCIES AND LATENCIES OF TUMOR FORMATION, AND TUMOR DIFFERENTIATIONS. ALTHOUGH SPONTANEOUSLY TRANSFORMED WB-F344 CELLS PRODUCED DIVERSE TUMOR TYPES (INCLUDING HEPATOCELLULAR CARCINOMAS, CHOLANGIOCARCINOMAS, HEPATOBLASTOMAS, AND OSTEOGENIC SARCOMAS), INDIVIDUAL LINEAGES YIELDED TUMORS WITH CONSISTENT AND SPECIFIC PATTERNS OF DIFFERENTIATION. THESE RESULTS PROVIDE SUBSTANTIAL EVIDENCE THAT THE STOCHASTIC ACCUMULATION OF INDEPENDENT TRANSFORMING EVENTS DURING THE SELECTION REGIMEN IN VITRO WERE RESPONSIBLE FOR SPONTANEOUS NEOPLASTIC TRANSFORMATION OF WB-F344 CELLS. FURTHERMORE, CELL LINEAGE COMMITMENT TO A SPECIFIC DIFFERENTIATION PROGRAM WAS STABLE WITH TIME IN CULTURE AND WITH SITE OF TRANSPLANTATION. THIS IS THE FIRST REPORT OF A COHORT OF RELATED, BUT INDEPENDENT, RAT LIVER EPITHELIAL CELL LINES THAT COLLECTIVELY PRODUCE A SPECTRUM OF TUMOR TYPES BUT INDIVIDUALLY REPRODUCE A SPECIFIC TUMOR TYPE. THESE CELL LINES WILL PROVIDE VALUABLE REAGENTS FOR INVESTIGATION OF THE MOLECULAR MECHANISMS INVOLVED IN THE DIFFERENTIATION OF HEPATIC STEM-LIKE CELLS AND FOR EXAMINATION OF POTENTIAL CAUSAL RELATIONSHIPS IN SPONTANEOUSLY TRANSFORMED RAT LIVER EPITHELIAL CELL LINES BETWEEN MOLECULAR/CELLULAR ALTERATIONS AND THE ABILITY TO PRODUCE TUMORS IN SYNGENEIC ANIMALS. 1998 5 4837 20 ONCOGENIC GENE EXPRESSION AND EPIGENETIC REMODELING OF CIS-REGULATORY ELEMENTS IN ASXL1-MUTANT CHRONIC MYELOMONOCYTIC LEUKEMIA. MYELOID NEOPLASMS ARE CLONAL HEMATOPOIETIC STEM CELL DISORDERS DRIVEN BY THE SEQUENTIAL ACQUISITION OF RECURRENT GENETIC LESIONS. TRUNCATING MUTATIONS IN THE CHROMATIN REMODELER ASXL1 (ASXL1(MT)) ARE ASSOCIATED WITH A HIGH-RISK DISEASE PHENOTYPE WITH INCREASED PROLIFERATION, EPIGENETIC THERAPEUTIC RESISTANCE, AND POOR SURVIVAL OUTCOMES. WE PERFORMED A MULTI-OMICS INTERROGATION TO DEFINE GENE EXPRESSION AND CHROMATIN REMODELING ASSOCIATED WITH ASXL1(MT) IN CHRONIC MYELOMONOCYTIC LEUKEMIA (CMML). ASXL1(MT) ARE ASSOCIATED WITH A LOSS OF REPRESSIVE HISTONE METHYLATION AND INCREASE IN PERMISSIVE HISTONE METHYLATION AND ACETYLATION IN PROMOTER REGIONS. ASXL1(MT) ARE FURTHER ASSOCIATED WITH DE NOVO ACCESSIBILITY OF DISTAL ENHANCERS BINDING ETS TRANSCRIPTION FACTORS, TARGETING IMPORTANT LEUKEMOGENIC DRIVER GENES. CHROMATIN REMODELING OF PROMOTERS AND ENHANCERS IS STRONGLY ASSOCIATED WITH GENE EXPRESSION AND HETEROGENOUS AMONG OVEREXPRESSED GENES. THESE RESULTS PROVIDE A COMPREHENSIVE MAP OF THE TRANSCRIPTOME AND CHROMATIN LANDSCAPE OF ASXL1(MT) CMML, FORMING AN IMPORTANT FRAMEWORK FOR THE DEVELOPMENT OF NOVEL THERAPEUTIC STRATEGIES TARGETING ONCOGENIC CIS INTERACTIONS. 2022 6 2935 17 GENETIC ALTERATION ASSOCIATED WITH CHRONIC LYMPHOCYTIC LEUKEMIA. THE GENETICS OF B-CELL CHRONIC LYMPHOCYTIC LEUKEMIA (B-CLL) DIFFER CONSIDERABLY FROM MOST OTHER FORMS OF HEMATOLOGIC MALIGNANCY WHICH ARE USUALLY CHARACTERIZED BY CHROMOSOME TRANSLOCATIONS. B-CLL TYPICALLY CONTAINS CHROMOSOMAL DELETIONS AND CHROMOSOMES 13Q14 AND 11Q22-->Q23 ARE THE MOST COMMON. THESE TWO REGIONS APPEAR TO SHARE A COMMON ANCESTRAL ORIGIN (AUER ET AL., 2007B). OVERALL, CHROMOSOMAL ABNORMALITIES CAN BE FOUND IN THE MAJORITY OF PATIENTS WITH B-CLL WHEN USING SENSITIVE TECHNIQUES (DOHNERET AL., 2000) AND POSSIBLY REFLECTS AN UNDERLYING PREDISPOSITION, WITH A SMALL BUT SIGNIFICANT NUMBER OF FAMILIAL CASES. ALTHOUGH SINGLE AND CONSISTENT ABNORMALITIES ARE MOST COMMON, MULTIPLE REARRANGEMENTS CAN OCCUR, OFTEN WITH DISEASE PROGRESSION (FEGANETAL., 1995; DOHNER ET AL., 2000). REGIONS OF RECURRENT DELETION SUGGEST THE PRESENCE OF TUMOR SUPPRESSOR GENES IF FOLLOWING KNUDSON'S THEORETICAL 2-HIT MODEL. HOWEVER, DESPITE EXTENSIVE SEQUENCING ANALYSIS OVER THE LAST DECADE AND LACK OF PATHOGENIC MUTATIONS IDENTIFIED, THERE HAS BEEN A MOVE AWAY FROM THIS SUGGESTED HYPOTHESIS AND ALTERNATIVE MECHANISMS OF GENE INACTIVATION INVOLVING EPIGENETIC SILENCING OR HAPLOINSUFFICIENCY MAY BE CONSIDERED AS MORE LIKELY IN THIS DISEASE. THIS REVIEW FOCUSES ON THE COMMON GENETIC ABNORMALITIES IN B-CLL AND RELATES THEM TO SOME OF THE MORE RECENT HYPOTHESES ON INACTIVATION OF GENES WITHIN THESE REGIONS OF DELETION. 2007 7 1260 14 CURRENT VIEWS ON THE INTERPLAY BETWEEN TYROSINE KINASES AND PHOSPHATASES IN CHRONIC MYELOID LEUKEMIA. CHRONIC MYELOID LEUKEMIA (CML) IS A MYELOPROLIFERATIVE DISORDER CHARACTERIZED BY BCR-ABL1 ONCOGENE EXPRESSION. THIS DYSREGULATED PROTEIN-TYROSINE KINASE (PTK) IS KNOWN AS THE PRINCIPAL DRIVER OF THE DISEASE AND IS TARGETED BY TYROSINE KINASE INHIBITORS (TKIS). EXTENSIVE DOCUMENTATION HAS ELUCIDATED HOW THE TRANSFORMATION OF MALIGNANT CELLS IS CHARACTERIZED BY MULTIPLE GENETIC/EPIGENETIC CHANGES LEADING TO THE LOSS OF TUMOR-SUPPRESSOR GENES FUNCTION OR PROTO-ONCOGENES EXPRESSION. THE IMPAIRMENT OF ADEQUATE LEVELS OF SUBSTRATES PHOSPHORYLATION, THUS AFFECTING THE BALANCE PTKS AND PROTEIN PHOSPHATASES (PPS), REPRESENTS A WELL-ESTABLISHED CELLULAR MECHANISM TO ESCAPE FROM SELF-LIMITING SIGNALS. IN THIS REVIEW, WE FOCUS OUR ATTENTION ON THE CHARACTERIZATION OF AND INTERACTIONS BETWEEN PTKS AND PPS, EMPHASIZING THEIR BIOLOGICAL ROLES IN DISEASE EXPANSION, THE REGULATION OF LSCS AND TKI RESISTANCE. WE DECIDED TO SEPARATE THOSE PPS THAT HAVE BEEN VALIDATED IN PRIMARY CELL MODELS OR LEUKEMIA MOUSE MODELS FROM THOSE WHOSE STUDIES HAVE BEEN PERFORMED ONLY IN CELL LINES (AND, THUS, REQUIRE VALIDATION), AS THERE MAY BE DIFFERENCES IN THE MANNER THAT THE ASSOCIATED PATHWAYS ARE MODIFIED UNDER THESE TWO CONDITIONS. THIS REVIEW SUMMARIZES THE ROLES OF DIVERSE PPS, WITH HOPE THAT BETTER KNOWLEDGE OF THE INTERPLAY AMONG PHOSPHATASES AND KINASES WILL EVENTUALLY RESULT IN A BETTER UNDERSTANDING OF THIS DISEASE AND CONTRIBUTE TO ITS ERADICATION. 2021 8 6222 15 THE LANDSCAPE OF SOMATIC MUTATIONS IN LYMPHOBLASTOID CELL LINES. SOMATIC MUTATIONS HAVE IMPORTANT BIOLOGICAL RAMIFICATIONS WHILE EXERTING SUBSTANTIAL RATE, TYPE, AND GENOMIC LOCATION HETEROGENEITY. YET, THEIR SPORADIC OCCURRENCE MAKES THEM DIFFICULT TO STUDY AT SCALE AND ACROSS INDIVIDUALS. LYMPHOBLASTOID CELL LINES (LCLS), A MODEL SYSTEM FOR HUMAN POPULATION AND FUNCTIONAL GENOMICS, HARBOR LARGE NUMBERS OF SOMATIC MUTATIONS AND HAVE BEEN EXTENSIVELY GENOTYPED. BY COMPARING 1,662 LCLS, WE REPORT THAT THE MUTATIONAL LANDSCAPE OF THE GENOME VARIES ACROSS INDIVIDUALS IN TERMS OF THE NUMBER OF MUTATIONS, THEIR GENOMIC LOCATIONS, AND THEIR SPECTRA; THIS VARIATION MAY ITSELF BE MODULATED BY SOMATIC TRANS-ACTING MUTATIONS. MUTATIONS ATTRIBUTED TO THE TRANSLESION DNA POLYMERASE ETA FOLLOW TWO DIFFERENT MODES OF FORMATION, WITH ONE MODE ACCOUNTING FOR THE HYPERMUTABILITY OF THE INACTIVE X CHROMOSOME. NONETHELESS, THE DISTRIBUTION OF MUTATIONS ALONG THE INACTIVE X CHROMOSOME APPEARS TO FOLLOW AN EPIGENETIC MEMORY OF THE ACTIVE FORM. 2023 9 2462 16 EPIGENETIC THERAPY OF MYELODYSPLASTIC SYNDROMES CONNECTS TO CELLULAR DIFFERENTIATION INDEPENDENTLY OF ENDOGENOUS RETROELEMENT DEREPRESSION. BACKGROUND: MYELODYSPLASTIC SYNDROMES (MDS) AND ACUTE MYELOID LEUKAEMIA (AML) ARE CHARACTERISED BY ABNORMAL EPIGENETIC REPRESSION AND DIFFERENTIATION OF BONE MARROW HAEMATOPOIETIC STEM CELLS (HSCS). DRUGS THAT REVERSE EPIGENETIC REPRESSION, SUCH AS 5-AZACYTIDINE (5-AZA), INDUCE HAEMATOLOGICAL IMPROVEMENT IN HALF OF TREATED PATIENTS. ALTHOUGH THE MECHANISMS UNDERLYING THERAPY SUCCESS ARE NOT YET CLEAR, INDUCTION OF ENDOGENOUS RETROELEMENTS (ERES) HAS BEEN HYPOTHESISED. METHODS: USING RNA SEQUENCING (RNA-SEQ), WE COMPARED THE TRANSCRIPTION OF ERES IN BONE MARROW HSCS FROM A NEW COHORT OF MDS AND CHRONIC MYELOMONOCYTIC LEUKAEMIA (CMML) PATIENTS BEFORE AND AFTER 5-AZA TREATMENT WITH HSCS FROM HEALTHY DONORS AND AML PATIENTS. WE FURTHER EXAMINED ERE TRANSCRIPTION USING THE MOST COMPREHENSIVE ANNOTATION OF ERE-OVERLAPPING TRANSCRIPTS EXPRESSED IN HSCS, GENERATED HERE BY DE NOVO TRANSCRIPT ASSEMBLY AND SUPPORTED BY FULL-LENGTH RNA-SEQ. RESULTS: CONSISTENT WITH PRIOR REPORTS, WE FOUND THAT TREATMENT WITH 5-AZA INCREASED THE REPRESENTATION OF ERE-DERIVED RNA-SEQ READS IN THE TRANSCRIPTOME. HOWEVER, SUCH INCREASES WERE COMPARABLE BETWEEN TREATMENT RESPONSES AND FAILURES. THE EXTENDED VIEW OF HSC TRANSCRIPTIONAL DIVERSITY OFFERED BY DE NOVO TRANSCRIPT ASSEMBLY ARGUED AGAINST 5-AZA-RESPONSIVE ERES AS DETERMINANTS OF THE OUTCOME OF THERAPY. INSTEAD, IT UNCOVERED PRE-TREATMENT EXPRESSION AND ALTERNATIVE SPLICING OF DEVELOPMENTALLY REGULATED GENE TRANSCRIPTS AS PREDICTORS OF THE RESPONSE OF MDS AND CMML PATIENTS TO 5-AZA TREATMENT. CONCLUSIONS: OUR STUDY IDENTIFIES THE DEVELOPMENTALLY REGULATED TRANSCRIPTIONAL SIGNATURES OF PROTEIN-CODING AND NON-CODING GENES, RATHER THAN ERES, AS CORRELATES OF A FAVOURABLE RESPONSE OF MDS AND CMML PATIENTS TO 5-AZA TREATMENT AND OFFERS NOVEL CANDIDATES FOR FURTHER EVALUATION. 2019 10 6584 15 TRIGGERING RECEPTORS EXPRESSED ON MYELOID CELLS 1 : OUR NEW PARTNER IN HUMAN ONCOLOGY? INFLAMMATION IS RECOGNIZED AS ONE OF THE HALLMARKS OF CANCER. INDEED, STRONG EVIDENCE INDICATES THAT CHRONIC INFLAMMATION PLAYS A MAJOR ROLE IN ONCOGENESIS, PROMOTING GENOME INSTABILITY, EPIGENETIC ALTERATIONS, PROLIFERATION AND DISSEMINATION OF CANCER CELLS. MONONUCLEAR PHAGOCYTES (MPS) HAVE BEEN IDENTIFIED AS KEY CONTRIBUTORS OF THE INFLAMMATORY INFILTRATE IN SEVERAL SOLID HUMAN NEOPLASIA, PROMOTING ANGIOGENESIS AND CANCER PROGRESSION. ONE OF THE MOST DESCRIBED AMPLIFIERS OF MPS PRO-INFLAMMATORY INNATE IMMUNE RESPONSE IS THE TRIGGERING RECEPTORS EXPRESSED ON MYELOID CELLS 1 (TREM-1). GROWING EVIDENCE SUGGESTS TREM-1 INVOLVEMENT IN ONCOGENESIS THROUGH CANCER RELATED INFLAMMATION AND THE SURROUNDING TUMOR MICROENVIRONMENT. IN HUMAN ONCOLOGY, HIGH LEVELS OF TREM-1 AND/OR ITS SOLUBLE FORM HAVE BEEN ASSOCIATED WITH POORER SURVIVAL DATA IN SEVERAL SOLID MALIGNANCIES, ESPECIALLY IN HEPATOCELLULAR CARCINOMA AND LUNG CANCER. TREM-1 SHOULD BE CONSIDERED AS A POTENTIAL BIOMARKER IN HUMAN ONCOLOGY AND COULD BE USED AS A NEW THERAPEUTIC TARGET OF INTEREST IN HUMAN ONCOLOGY (TREM-1 INHIBITORS, TREM-1 AGONISTS). MORE CLINICAL STUDIES ARE URGENTLY NEEDED TO CONFIRM TREM-1 (AND TREM FAMILY) ROLES IN THE PROGNOSIS AND THE TREATMENT OF HUMAN SOLID CANCERS. 2022 11 3316 15 HISTIOCYTIC SARCOMA AS A SECONDARY MALIGNANCY: PATHOBIOLOGY, DIAGNOSIS, AND TREATMENT. HISTIOCYTIC SARCOMA (HS) IS AN EXTREMELY RARE NON-LANGERHANS CELL DISORDER WITH AN AGGRESSIVE COURSE AND LIMITED TREATMENT OPTIONS. RECENT ADVANCES IN MOLECULAR/GENETIC SEQUENCING HAVE SUGGESTED A COMMON CLONAL ORIGIN BETWEEN VARIOUS HEMATOLYMPHOID DISORDERS AND CASES OF SECONDARY HS. DERIVING CONCLUSIONS FROM PREVIOUSLY REPORTED CASES OF HS ARISING SECONDARILY TO CERTAIN HEMATOLYMPHOID DISORDERS, HERE WE HAVE TRIED TO PROVIDE INSIGHT INTO THE MECHANISMS INFLUENCING THIS EVOLUTION. WE ALSO DISCUSS A CLINICAL CASE OF A 72-YEAR-OLD MAN WITH A DIAGNOSIS OF CHRONIC MYELOID LEUKEMIA (CML), PRESENTING SUBSEQUENTLY WITH A HETEROGENEOUS LIVER MASS POSITIVE WITH A DIAGNOSIS OF HS. THE LIVER MASS SHOWED A RETAINED BCR-ABL1 TRANSLOCATION SUGGESTING CLONALITY BETWEEN THE CML AND HS. AS SEEN IN OUR CASE AND OTHER REPORTED CASES OF HS DERIVED SECONDARILY, THE CONCURRENT EXPRESSION OF IMMUNOGLOBULIN HEAVY (IGH)-/LIGHT-CHAIN REARRANGEMENTS OR CYTOGENETIC MARKERS COMMON TO THE PRIMARY MALIGNANCY SUGGESTS AN EVOLUTIONARY MECHANISM INVOLVING LINEAGE SWITCHING THAT COULD POTENTIALLY BE INFLUENCED BY GENETIC OR EPIGENETIC CUES WHICH MAY OCCUR AT THE LEVEL OF A PROGENITOR OR THE MALIGNANT CELL ITSELF. 2016 12 2469 9 EPIGENETIC TRAJECTORIES OF THE PREMALIGNANT-TO-MALIGNANT TRANSITION OF CHRONIC LYMPHOCYTIC LEUKEMIA. KRETZMER AND COLLEAGUES SHOW THAT THE TRANSITION TO ALTERED METHYLOME OCCURS VERY EARLY IN CHRONIC LYMPHOCYTIC LEUKEMIA, AND ONCE ACQUIRED, IT IS A CLONAL AND EXTREMELY STABLE CHANGE. HOWEVER, THE PRECISE TIME POINT WHEN THE LEUKEMIC CLONE STARTS DEVIATING SIGNIFICANTLY FROM THE NORMAL B-CELL DIFFERENTIATION TRAJECTORY IS STILL ELUSIVE. SEE RELATED ARTICLE BY KRETZMER ET AL., P. 54. 2021 13 5249 23 PROGRAMMED CELL DEATH-1 PATHWAY INHIBITION IN MYELOID MALIGNANCIES: IMPLICATIONS FOR MYELOPROLIFERATIVE NEOPLASMS. MYELOPROLIFERATIVE NEOPLASMS (MPNS) ARE CLONAL HEMATOPOIETIC DISEASES THAT BELONG TO THE SPECTRUM OF MYELOID MALIGNANCIES (MYMS), WHICH ALSO INCLUDE MYELODYSPLASTIC SYNDROMES (MDS), ACUTE MYELOID LEUKEMIA (AML), AND CHRONIC MYELOGENOUS LEUKEMIA (CML). WHILE HEMATOPOIETIC STEM CELL TRANSPLANTATION (HSCT) IS A POTENTIALLY CURATIVE THERAPEUTIC APPROACH TO MANY MYMS, THE ASSOCIATED MORBIDITY AND MORTALITY HAVE NECESSITATED THE DEVELOPMENT OF NON-HSCT THERAPEUTICS FOR SYMPTOM MANAGEMENT AND DISEASE COURSE MODIFICATION. IMMUNE CHECKPOINT INHIBITION, IN PARTICULAR ALONG THE PROGRAMMED CELL DEATH PROTEIN 1 (PD-1)/B7-H1 (PD-L1) AXIS, IS AN ESTABLISHED STRATEGY IN SOLID TUMORS WITH POTENTIAL AS AN ADJUNCTIVE THERAPY IN HEMATOLOGIC MALIGNANCIES. SEMINAL STUDIES SUGGEST THAT THE PRO-INFLAMMATORY MICROENVIRONMENT OF MYMS CAN SUPPRESS T LYMPHOCYTE-MEDIATED IMMUNITY VIA PD-1 SIGNALING AND THAT RESPONSE TO MAINSTAY EPIGENETIC THERAPIES FOR MYMS MAY BE GOVERNED BY PD-1 GENE REGULATION. ALTHOUGH THE ROLE OF PD-1 SIGNALING IN MPN PATHOGENESIS AND PROGRESSION IS AS YET UNCLEAR, RESEARCH IN MPN PATIENTS HAS REVEALED EXPANSION OF MYELOID-DERIVED SUPPRESSOR CELLS (MDSCS), WHICH MAY EFFECT HOST IMMUNE TOLERANCE OF TUMOR VIA TEMPORALLY AND SPATIALLY SPECIFIC ACTIVATION OF PD-1/PD-L1 SIGNALING. THE CURRENT UNDERSTANDING OF IMMUNE DYSFUNCTION IN MPNS AND ANALOGOUS MYMS OFFERS A COMPELLING RATIONALE TO STUDY PD-1/PD-L1 INHIBITION IN PATIENTS AS A NOVEL TREATMENT OPTION. 2017 14 1043 22 CLINICAL CHARACTERISTICS AND WHOLE EXOME/TRANSCRIPTOME SEQUENCING OF COEXISTING CHRONIC MYELOID LEUKEMIA AND MYELOFIBROSIS. MYELOPROLIFERATIVE NEOPLASMS (MPNS) ARE CLONAL HEMATOPOIETIC STEM CELL (HSC) DISORDERS THAT CAN BE CLASSIFIED ON THE BASIS OF GENETIC, CLINICAL, PHENOTYPIC FEATURES. GENETIC LESIONS SUCH AS JAK2 MUTATIONS AND BCR-ABL TRANSLOCATION ARE OFTEN MUTUALLY EXCLUSIVE IN MPN PATIENTS AND LEAD TO ESSENTIAL THROMBOCYTHEMIA, POLYCYTHEMIA VERA, OR MYELOFIBROSIS OR CHRONIC MYELOID LEUKEMIA, RESPECTIVELY. NEVERTHELESS, COEXISTENCE OF THESE GENETIC ABERRATIONS IN THE SAME PATIENT HAS BEEN REPORTED. WHETHER THESE ABERRATIONS OCCUR IN THE SAME STEM CELL OR A DIFFERENT CELL IS UNCLEAR, BUT AN UNSTABLE GENOME IN THE HSCS SEEMS TO BE THE COMMON ANTECEDENT. IN AN EFFORT TO CHARACTERIZE THE UNDERLYING GENETIC EVENTS THAT MIGHT CONTRIBUTE TO THE APPEARANCE OF MORE THAN ONE MPN IN A PATIENT, WE STUDIED NEOPLASTIC CELLS FROM PATIENTS WITH DUAL MPNS BY NEXT-GENERATION SEQUENCING. WE OBSERVED THAT MOST PATIENTS WITH TWO MPNS HARBORED MUTATIONS IN GENES KNOWN TO CONTRIBUTE TO CLONAL HEMATOPOIESIS THROUGH ALTERED EPIGENETIC REGULATION SUCH AS TET2, ASXL1/2, SRSF2, AND IDH2 AT VARYING FREQUENCIES (1%-47%). IN ADDITION, WE FOUND THAT SOME PATIENTS ALSO HARBORED ONCOGENIC MUTATIONS IN N/KRAS, TP53, BRAF, EZH2, AND GNAS AT LOW FREQUENCIES, WHICH PROBABLY REPRESENT CLONAL EVOLUTION. THESE FINDINGS SUPPORT THE HYPOTHESIS THAT HEMATOPOIETIC CELLS FROM MPN PATIENTS HARBOR MULTIPLE GENETIC ABERRATIONS, SOME OF WHICH CAN CONTRIBUTE TO CLONAL DOMINANCE. ACQUIRING MUTATIONS IN JAK2/CALR/MPL OR THE BCR-ABL TRANSLOCATION PROBABLY DRIVE THE ONCOGENIC PHENOTYPE TOWARDS A SPECIFIC MPN. FURTHER, WE PROPOSE THAT THE ACQUISITION OF BCR-ABL IN THESE PATIENTS IS FREQUENTLY A SECONDARY EVENT RESULTING FROM AN UNSTABLE GENOME. 2017 15 4388 22 MLL2/KMT2D AND MLL3/KMT2C EXPRESSION CORRELATES WITH DISEASE PROGRESSION AND RESPONSE TO IMATINIB MESYLATE IN CHRONIC MYELOID LEUKEMIA. BACKGROUND: CHRONIC MYELOID LEUKEMIA (CML) IS A CLONAL MYELOPROLIFERATIVE NEOPLASM WHOSE PATHOGENESIS IS LINKED TO THE PHILADELPHIA CHROMOSOME PRESENCE THAT GENERATES THE BCR-ABL1 FUSION ONCOGENE. TYROSINE KINASE INHIBITORS (TKI) SUCH AS IMATINIB MESYLATE (IM) DRAMATICALLY IMPROVED THE TREATMENT EFFICIENCY AND SURVIVAL OF CML PATIENTS BY TARGETING BCR-ABL TYROSINE KINASE. THE DISEASE SHOWS THREE DISTINCT CLINICAL-LABORATORY STAGES: CHRONIC PHASE, ACCELERATED PHASE AND BLAST CRISIS. ALTHOUGH PATIENTS IN THE CHRONIC PHASE RESPOND WELL TO TREATMENT, PATIENTS IN THE ACCELERATED PHASE OR BLAST CRISIS USUALLY SHOW THERAPY RESISTANCE AND CML RELAPSE. IT IS CRUCIAL, THEREFORE, TO IDENTIFY BIOMARKERS TO PREDICT CML GENETIC EVOLUTION AND RESISTANCE TO TKI THERAPY, CONSIDERING NOT ONLY THE EFFECTS OF GENETIC ABERRATIONS BUT ALSO THE ROLE OF EPIGENETIC ALTERATIONS DURING THE DISEASE. ALTHOUGH DYSREGULATIONS IN EPIGENETIC MODULATORS SUCH AS HISTONE METHYLTRASNFERASES HAVE ALREADY BEEN DESCRIBED FOR SOME HEMATOLOGIC MALIGNANCIES, TO DATE VERY LIMITED DATA IS AVAILABLE FOR CML, ESPECIALLY WHEN CONSIDERING THE LYSINE METHYLTRANSFERASE MLL2/KMT2D AND MLL3/KMT2C. METHODS: HERE WE INVESTIGATED THE EXPRESSION PROFILE OF BOTH GENES IN CML PATIENTS IN DIFFERENT STAGES OF THE DISEASE, IN PATIENTS SHOWING DIFFERENT RESPONSES TO THERAPY WITH IM AND IN NON-NEOPLASTIC CONTROL SAMPLES. IMATINIB SENSITIVE AND RESISTANT CML CELL LINES WERE ALSO USED TO INVESTIGATE WHETHER TREATMENT WITH OTHER TYROSINE KINASE INHIBITORS INTERFERED IN THEIR EXPRESSION. RESULTS: IN PATIENTS, BOTH METHYLTRANSFERASES WERE EITHER UPREGULATED OR WITH BASAL EXPRESSION LEVEL DURING THE CHRONIC PHASE COMPARED TO CONTROLS. INTERESTINGLY, MLL3/KMT2C AND SPECIALLY MLL2/KMT2D LEVELS DECREASED DURING DISEASE PROGRESSION CORRELATING WITH DISTINCT CLINICAL STAGES. FURTHERMORE, MLL2/KMT2D WAS DECREASED IN PATIENTS RESISTANT TO IM TREATMENT. A RESCUE IN THE EXPRESSION OF BOTH MLL GENES WAS OBSERVED IN KCL22S, A CML CELL LINE SENSITIVE TO IM, AFTER TREATMENT WITH DASATINIB OR NILOTINIB WHICH WAS ASSOCIATED WITH A HIGHER RATE OF APOPTOSIS, AN ENHANCED EXPRESSION OF P21 (CDKN1A) AND A CONCOMITANT DECREASE IN THE EXPRESSION OF CDK2, CDK4 AND CYCLIN B1 (CCNB1) IN COMPARISON TO UNTREATED KCL22S CONTROL OR IM RESISTANT KCL22R CELL LINE, WHICH SUGGESTS INVOLVEMENT OF P53 REGULATED PATHWAY. CONCLUSION: OUR RESULTS ESTABLISHED A NEW ASSOCIATION BETWEEN MLL2/KMT2D AND MLL3/KMT2C GENES WITH CML AND SUGGEST THAT MLL2/KMT2D IS ASSOCIATED WITH DISEASE EVOLUTION AND MAY BE A POTENTIAL MARKER TO PREDICT THE DEVELOPMENT OF THERAPY RESISTANCE. 2018 16 4545 17 MUTANT P53 GAIN OF FUNCTION AND CHEMORESISTANCE: THE ROLE OF MUTANT P53 IN RESPONSE TO CLINICAL CHEMOTHERAPY. PURPOSE: TO REVIEW MECHANISMS UNDERLYING MUTANT P53 (MUTP53) GAIN OF FUNCTION (GOF) AND MUTP53-INDUCED CHEMORESISTANCE, AND TO INVESTIGATE THE ROLE OF MUTP53 IN RESPONSE TO CLINICAL CHEMOTHERAPY. METHODS: WE SEARCHED THE PUBMED DATABASE FOR CLINICAL STUDIES FROM THE PAST DECADE, INCLUDING DATA EVALUATING THE IMPACT OF MUTP53 IN CLINICAL CHEMOTHERAPY RESPONSE. RESULTS: INTERACTIONS BETWEEN MUTP53 AND TRANSCRIPTIONAL FACTORS, PROTEINS OR DNA STRUCTURES, AS WELL AS EPIGENETIC REGULATION, CONTRIBUTE TO MUTP53 GOF. MAJOR MECHANISMS OF MUTP53-INDUCED CHEMORESISTANCE INCLUDE ENHANCED DRUG EFFLUX AND METABOLISM, PROMOTING SURVIVAL, INHIBITING APOPTOSIS, UPREGULATING DNA REPAIR, SUPPRESSING AUTOPHAGY, ELEVATING MICROENVIRONMENTAL RESISTANCE AND INDUCING A STEM-LIKE PHENOTYPE. CLINICALLY, MUTP53 PREDICTED RESISTANCE TO CHEMOTHERAPY IN DIFFUSE LARGE B-CELL LYMPHOMA, AND ESOPHAGEAL AND OROPHARYNGEAL CANCERS, BUT ITS IMPACT ON CHRONIC LYMPHOCYTIC LEUKEMIA WAS UNCLEAR. IN BLADDER CANCER, MUTP53 DID NOT PREDICT RESISTANCE, WHEREAS IN SOME BREAST AND OVARIAN CANCERS, IT WAS ASSOCIATED WITH SENSITIVITY TO CERTAIN CHEMOTHERAPEUTIC AGENTS. CONCLUSION: MUTP53 HAS AN INTRICATE ROLE IN THE RESPONSE TO CLINICAL CHEMOTHERAPY AND SHOULD NOT BE INTERPRETED IN ISOLATION. FURTHERMORE, WHEN PREDICTING TUMOR RESPONSE TO CHEMOTHERAPY BASED ON THE P53 STATUS, THE DRUGS USED SHOULD ALSO BE TAKEN INTO CONSIDERATION. THESE CONCEPTS REQUIRE FURTHER INVESTIGATION. 2017 17 2637 17 EPIGENOME-WIDE STUDY IDENTIFIES EPIGENETIC OUTLIERS IN NORMAL MUCOSA OF PATIENTS WITH COLORECTAL CANCER. NONGENETIC PREDISPOSITION TO COLORECTAL CANCER CONTINUES TO BE DIFFICULT TO MEASURE PRECISELY, HAMPERING EFFORTS IN TARGETED PREVENTION AND SCREENING. EPIGENETIC CHANGES IN THE NORMAL MUCOSA OF PATIENTS WITH COLORECTAL CANCER CAN SERVE AS A TOOL IN PREDICTING COLORECTAL CANCER OUTCOMES. WE IDENTIFIED EPIGENETIC CHANGES AFFECTING THE NORMAL MUCOSA OF PATIENTS WITH COLORECTAL CANCER. DNA METHYLATION PROFILING ON NORMAL COLON MUCOSA FROM 77 PATIENTS WITH COLORECTAL CANCER AND 68 CONTROLS IDENTIFIED A DISTINCT SUBGROUP OF NORMALLY-APPEARING MUCOSA WITH MARKEDLY DISRUPTED DNA METHYLATION AT A LARGE NUMBER OF CPGS, TERMED AS "OUTLIER METHYLATION PHENOTYPE" (OMP) AND ARE PRESENT IN 15 OF 77 PATIENTS WITH CANCER VERSUS 0 OF 68 CONTROLS (P < 0.001). SIMILAR FINDINGS WERE ALSO SEEN IN PUBLICLY AVAILABLE DATASETS. COMPARISON OF NORMAL COLON MUCOSA TRANSCRIPTION PROFILES OF PATIENTS WITH OMP CANCER WITH THOSE OF PATIENTS WITH NON-OMP CANCER INDICATES GENES WHOSE PROMOTERS ARE HYPERMETHYLATED IN THE OMP PATIENTS ARE ALSO TRANSCRIPTIONALLY DOWNREGULATED, AND THAT MANY OF THE GENES MOST AFFECTED ARE INVOLVED IN INTERACTIONS BETWEEN EPITHELIAL CELLS, THE MUCUS LAYER, AND THE MICROBIOME. ANALYSIS OF 16S RRNA PROFILES SUGGESTS THAT NORMAL COLON MUCOSA OF OMPS ARE ENRICHED IN BACTERIAL GENERA ASSOCIATED WITH COLORECTAL CANCER RISK, ADVANCED TUMOR STAGE, CHRONIC INTESTINAL INFLAMMATION, MALIGNANT TRANSFORMATION, NOSOCOMIAL INFECTIONS, AND KRAS MUTATIONS. IN CONCLUSION, OUR STUDY IDENTIFIES AN EPIGENETICALLY DISTINCT OMP GROUP IN THE NORMAL MUCOSA OF PATIENTS WITH COLORECTAL CANCER THAT IS CHARACTERIZED BY A DISRUPTED METHYLOME, ALTERED GENE EXPRESSION, AND MICROBIAL DYSBIOSIS. PROSPECTIVE STUDIES ARE NEEDED TO DETERMINE WHETHER OMP COULD SERVE AS A BIOMARKER FOR AN ELEVATED EPIGENETIC RISK FOR COLORECTAL CANCER DEVELOPMENT. PREVENTION RELEVANCE: OUR STUDY IDENTIFIES AN EPIGENETICALLY DISTINCT OMP GROUP IN THE NORMAL MUCOSA OF PATIENTS WITH COLORECTAL CANCER THAT IS CHARACTERIZED BY A DISRUPTED METHYLOME, ALTERED GENE EXPRESSION, AND MICROBIAL DYSBIOSIS. IDENTIFICATION OF OMPS IN HEALTHY CONTROLS AND PATIENTS WITH COLORECTAL CANCER WILL LEAD TO PREVENTION AND BETTER PROGNOSIS, RESPECTIVELY. 2022 18 5688 15 SILENCING EFFECTS OF MUTANT RAS SIGNALLING ON TRANSCRIPTOMES. MUTATED GENES OF THE RAS FAMILY ENCODING SMALL GTP-BINDING PROTEINS DRIVE NUMEROUS CANCERS, INCLUDING PANCREATIC, COLON AND LUNG TUMORS. BESIDES THE NUMEROUS EFFECTS OF MUTANT RAS GENE EXPRESSION ON ABERRANT PROLIFERATION, TRANSFORMED PHENOTYPES, METABOLISM, AND THERAPY RESISTANCE, THE MOST STRIKING CONSEQUENCES OF CHRONIC RAS ACTIVATION ARE CHANGES OF THE GENETIC PROGRAM. BY PERFORMING SYSTEMATIC GENE EXPRESSION STUDIES IN CELLULAR MODELS THAT ALLOW COMPARISONS OF PRE-NEOPLASTIC WITH RAS-TRANSFORMED CELLS, WE AND OTHERS HAVE ESTIMATED THAT 7 PERCENT OR MORE OF ALL TRANSCRIPTS ARE ALTERED IN CONJUNCTION WITH THE EXPRESSION OF THE ONCOGENE. IN THIS CONTEXT, THE NUMBER OF UP-REGULATED TRANSCRIPTS APPROXIMATES THAT OF DOWN-REGULATED TRANSCRIPTS. WHILE UP-REGULATED TRANSCRIPTION FACTORS SUCH AS MYC, FOSL1, AND HMGA2 HAVE BEEN IDENTIFIED AND CHARACTERIZED AS RAS-RESPONSIVE DRIVERS OF THE ALTERED TRANSCRIPTOME, THE SUPPRESSED FACTORS HAVE BEEN LESS WELL STUDIED AS POTENTIAL REGULATORS OF THE GENETIC PROGRAM AND TRANSFORMED PHENOTYPE IN THE BREADTH OF THEIR OCCURRENCE. WE THEREFORE HAVE COLLECTED INFORMATION ON DOWNREGULATED RAS-RESPONSIVE FACTORS AND DISCUSS THEIR POTENTIAL ROLE AS TUMOR SUPPRESSORS THAT ARE LIKELY TO ANTAGONIZE ACTIVE CANCER DRIVERS. TO BETTER UNDERSTAND THE ACTIVE MECHANISMS THAT ENTAIL ANTI-RAS FUNCTION AND THOSE THAT LEAD TO LOSS OF TUMOR SUPPRESSOR ACTIVITY, WE FOCUS ON THE TUMOR SUPPRESSOR HREV107 (ALIAS PLAAT3 [PHOSPHOLIPASE A AND ACYLTRANSFERASE 3], PLA2G16 [PHOSPHOLIPASE A2, GROUP XVI] AND HRASLS3 [HRAS-LIKE SUPPRESSOR 3]). INACTIVATING HREV107 MUTATIONS IN TUMORS ARE EXTREMELY RARE, HENCE EPIGENETIC CAUSES MODULATED BY THE RAS PATHWAY ARE LIKELY TO LEAD TO DOWN-REGULATION AND LOSS OF FUNCTION. 2023 19 409 17 ANALYSIS OF GENES ENCODING EPIGENETIC REGULATORS IN MYELOPROLIFERATIVE NEOPLASMS: COEXISTENCE OF A NOVEL SETBP1 MUTATION IN A PATIENT WITH A P.V617F JAK2 POSITIVE MYELOFIBROSIS. IN RECENT YEARS IT HAS BEEN SHOWN THAT THE CAUSES OF CHRONIC MYELOPROLIFERATIVE NEOPLASMS (MPNS) ARE MORE COMPLEX THAN A SIMPLE SIGNALING ABERRATION AND MANY OTHER MUTATED GENES AFFECTING DIFFERENT CELL PROCESSES HAVE BEEN DESCRIBED. FOR INSTANCE, MUTATIONS IN GENES ENCODING EPIGENETIC REGULATORS ARE MORE FREQUENT THAN EXPECTED. ONE OF THE LATEST GENES DESCRIBED AS MUTATED IS SET BINDING PROTEIN 1 (SETBP1). IN SILICO TOOLS HAVE REVEALED THAT THERE ARE SEVERAL HUMAN SETBP1 PARALOGOUS TO NUCLEAR RECEPTOR BINDING SET DOMAIN PROTEIN 1 (NSD1), NSD2 AND NSD3, FOR EXAMPLE, WHICH ARE ALSO INVOLVED IN THE DEVELOPMENT OF OTHER HEMATOLOGICAL MALIGNANCIES. THEREFORE, THE PRESENT STUDY ANALYZED THE MUTATIONAL STATUS OF NSD1, NSD2, NSD3 AND SETBP1 IN BCR-ABL1 NEGATIVE MPNS WITH OR WITHOUT JANUS KINASE 2 (JAK2) P.V617F MUTATION. THE PRESENT STUDY REVEALED THAT THE NSD GENES ARE NOT FREQUENTLY MUTATED IN MPNS. HOWEVER, A NOVEL SETBP1 MUTATION WAS IDENTIFIED IN A PATIENT WITH P.V617F JAK2 POSITIVE PRIMARY MYELOFIBROSIS. THESE RESULTS PROVIDE FURTHER INSIGHT INTO THE GENETIC COMPLEXITY OF MPNS. 2019 20 3693 20 INFLAMMATORY CELLS CAN ALTER THE LEVELS OF H3K9AC AND GAMMAH2AX IN DYSPLASTIC CELLS AND FAVOR TUMOR PHENOTYPE. ORAL POTENTIALLY MALIGNANT DISORDERS (OPMD) ARE CLINICAL PRESENTATIONS THAT CARRY AN INCREASED RISK OF CANCER DEVELOPMENT. CURRENTLY, EPITHELIAL DYSPLASIA GRADE IS BASED ON ARCHITECTURAL AND CYTOLOGICAL EPITHELIAL CHANGES AND IS USED TO PREDICT THE MALIGNANT TRANSFORMATION OF THESE LESIONS. HOWEVER, PREDICTING WHICH OPMD WILL PROGRESS TO A MALIGNANT TUMOR IS VERY CHALLENGING. INFLAMMATORY INFILTRATES CAN FAVOR CANCER DEVELOPMENT, AND RECENT STUDIES SUGGEST THAT THIS ASSOCIATION WITH OPMD LESIONS MAY BE RELATED TO THE ETIOLOGY AND/OR AGGRESSIVE CLINICAL BEHAVIOR OF THESE LESIONS. EPIGENETIC CHANGES SUCH AS HISTONE MODIFICATIONS MAY MEDIATE CHRONIC INFLAMMATION AND ALSO FAVOR TUMOR CELLS IN IMMUNE RESISTANCE AND EVASION. THIS STUDY AIMED TO EVALUATE THE RELATIONSHIP BETWEEN HISTONE ACETYLATION (H3K9AC) AND DNA DAMAGE IN THE CONTEXT OF DYSPLASTIC LESIONS WITH PROMINENT CHRONIC INFLAMMATION. IMMUNOFLUORESCENCE OF "LOW-RISK" AND "HIGH-RISK" OPMD LESIONS (N = 24) AND INFLAMMATORY FIBROUS HYPERPLASIA (N = 10) AS THE CONTROL GROUP WAS PERFORMED TO ASSESS HISTONE ACETYLATION LEVELS AND DNA DAMAGE THROUGH THE PHOSPHORYLATION OF H2AX (GAMMAH2AX). CELL CO-CULTURE ASSAYS WITH PBMCS AND ORAL KERATINOCYTE CELL LINES (NOK-SI, DOK, AND SCC-25) WERE PERFORMED TO ASSESS PROLIFERATION, ADHESION, MIGRATION, AND EPITHELIAL-MESENCHYMAL TRANSITION (EMT). ORAL DYSPLASTIC LESIONS SHOWED A HYPOACETYLATION OF H3K9 AND LOW LEVELS OF GAMMAH2AX COMPARED TO CONTROL. THE CONTACT OF DYSPLASTIC ORAL KERATINOCYTES WITH PBMCS FAVORED EMT AND THE LOSS OF CELL-CELL ADHESION. ON THE OTHER HAND, P27 LEVELS INCREASED AND CYCLIN E DECREASED IN DOK, INDICATING CELL CYCLE ARREST. WE CONCLUDE THAT THE PRESENCE OF CHRONIC INFLAMMATION ASSOCIATED TO DYSPLASTIC LESIONS IS CAPABLE OF PROMOTING EPIGENETIC ALTERATIONS, WHICH IN TURN CAN FAVOR THE PROCESS OF MALIGNANT TRANSFORMATION. 2023