1 3024 149 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 2 4430 35 MOLECULAR BIOLOGY OF ONCOGENIC INFLAMMATORY PROCESSES. I. NON-ONCOGENIC AND ONCOGENIC PATHOGENS, INTRINSIC INFLAMMATORY REACTIONS WITHOUT PATHOGENS, AND MICRORNA/DNA INTERACTIONS (REVIEW). IN SOME INFLAMMASOMES TUMOR CELLS ARE GENERATED. THE INTERNAL ENVIRONMENT OF THE INFLAMMASOME IS CONDUCIVE TO THE INDUCTION OF MALIGNANT TRANSFORMATION. EPIGENETIC CHANGES INITIATE THIS PROCESS. THE SUBVERTED STROMAL CONNECTIVE TISSUE CELLS ACT TO PROMOTE AND SUSTAIN THE PROCESS OF MALIGNANT TRANS-FORMATION. IN ITS EARLY STAGES, THE PREMALIGNANT CELLS DEPEND ON PARACRINE CIRCUITRIES FOR THE RECEPTION OF GROWTH FACTORS. THE LIGANDS ARE DERIVED FROM THE CONNECTIVE TISSUE, AND THE RECEPTORS ARE EXPRESSED ON THE RECIPIENT PREMALIGNANT CELLS. THE INITIAL EVENTS ARE NOT A DIRECT ATTACK ON THE PROTO-ONCOGENES, AND THUS IT MAY BE ENTIRELY REVERSIBLE. EPIGENETIC PROCESSES OF HYPERMETHYLATION OF THE GENES AT THE PROMOTERS OF TUMOR SUPPRESSOR GENES (TO SILENCE THEM), AND DEACETYLATION OF THE HISTONES AIMED AT THE PROMOTERS OF PROTO-ONCOGENES (TO ACTIVATE THEM) ARE ON-GOING. A LARGE NUMBER OF SHORT RNA SEQUENCES (INTERFERING, MICRO-, SHORT HAIRPIN, NON-CODING RNAS) SILENCE TUMOR SUPPRESSOR GENES, BY NEUTRALIZING THEIR MRNAS. IN A SERIAL SEQUENCE ONCOGENES UNDERGO AMPLIFICATIONS, POINT-MUTATIONS, TRANSLOCATIONS AND FUSIONS. IN ITS EARLIEST STAGE, THE PROCESS IS REVERSIBLE BY DEMETHYLATION OF THE SILENCED SUPPRESSOR GENE PROMOTERS (TO REACTIVATE THEM), OR RE-ACETYLATION OF THE HISTONES OF THE ONCOGENE PROMOTERS, THUS DE-ACTIVATING THEM. THE EXTERNAL ADMINISTRATION OF HISTONE DEACETYLASE INHIBITORS USUALLY LEADS TO THE RESTORATION OF HISTONE ACETYLATION. IN TIME, THE UNCORRECTED PROCESSES SOLIDIFY INTO CONSTITUTIVE AND IRREVERSIBLE GENE MUTATIONS. SOME OF THE PATHOGENS INDUCING INFLAMMATIONS WITH CONSQUENTIAL MALIGNANT TRANSFORMATION CONTAIN ONCOGENIC GENE SEQUENCES (PAPILLOMA VIRUSES, EPSTEIN-BARR VIRUS, KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS, HEPATITIS B AND C VIRUSES, MERKEL CELL POLYOMA VIRUS, HELICOBACTER PYLORI, ENTEROTOXIGENIC BACTEROIDES FRAGILIS). THESE INDUCED MALIGNANCIES MAY BE MULTIFOCAL. OTHER PATHOGENS ARE DEVOID OF ANY KNOWN ONCOGENIC GENOMIC SEQUENCES (MYCOPLASMA VAV-CARCINOGENESIS, CHLAMYDIA MALT-LYMPHOMA GENESIS). IN THESE CASES THE HOST'S INFLAMMATORY REACTIONS INDUCE THE MALIGNANT TRANSFORMATION IN SERIAL SEQUENCES OF GENE ALTERATIONS INITIATED BY HYPOXIA AND REACTIVE OXYGEN AND NITROGEN SPECIES GENERATION. CARCINOGENIC INTRINSIC INFLAMMATORY PROCESSES ENDOGENOUSLY INITIATED WITHOUT A PATHOGEN ARE RECOGNIZED. CHRONIC INFLAMMATORY PROCESSES SIGNAL THE RNA/DNA COMPLEX. IN RESPONSE, THE DNA MAY REVERT INTO ITS ANCIENT PRIMORDIAL 'IMMORTAL' FORMAT, WHICH THE CLINICS RECOGNIZE AS 'ONCOGENESIS'. THE DNA REMAINS THE ULTIMATE MASTER OF BIOENGINEERING IN ORDER TO SUSTAIN LIFE. A DISCUSSION ON THE MOST VERSATILE AND RESISTANT PRIMORDIAL RNA/DNA COMPLEX AND THE PRE-, PROTO-, AND UNICELLULAR WORLD IN WHICH THEY CO-EXISTED IS INCLUDED. 2012 3 5475 28 RESTORING MLL REACTIVATES LATENT TUMOR SUPPRESSION-MEDIATED VULNERABILITY TO PROTEASOME INHIBITORS. MLL UNDERGOES MULTIPLE DISTINCT CHROMOSOMAL TRANSLOCATIONS TO YIELD AGGRESSIVE LEUKEMIA WITH DISMAL OUTCOMES. BESIDES THEIR WELL-ESTABLISHED ROLE IN LEUKEMOGENESIS, MLL FUSIONS ALSO POSSESS LATENT TUMOR-SUPPRESSIVE ACTIVITY, WHICH CAN BE EXPLOITED AS EFFECTIVE CANCER TREATMENT STRATEGIES USING PHARMACOLOGICAL MEANS SUCH AS PROTEASOME INHIBITORS (PIS). HERE, USING MLL-REARRANGED XENOGRAFTS AND MLL LEUKEMIC CELLS AS MODELS, WE SHOW THAT WILD-TYPE MLL IS INDISPENSABLE FOR THE LATENT TUMOR-SUPPRESSIVE ACTIVITY OF MLL FUSIONS. MLL DYSFUNCTION, SHOWN AS LOSS OF THE CHROMATIN ACCUMULATION AND SUBSEQUENT DEGRADATION OF MLL, COMPROMISES THE LATENT TUMOR SUPPRESSION OF MLL-AF4 AND IS INSTRUMENTAL FOR THE ACQUIRED PI RESISTANCE. MECHANISTICALLY, MLL DYSFUNCTION IS CAUSED BY CHRONIC PI TREATMENT-INDUCED EPIGENETIC REPROGRAMMING THROUGH THE H2BUB-ASH2L-MLL AXIS AND CAN BE SPECIFICALLY RESTORED BY HISTONE DEACETYLASE (HDAC) INHIBITORS, WHICH INDUCE HISTONE ACETYLATION AND RECRUITS MLL ON CHROMATIN TO PROMOTE CELL CYCLE GENE EXPRESSION. OUR FINDINGS NOT ONLY DEMONSTRATE THE MECHANISM UNDERLYING THE INEVITABLE ACQUISITION OF PI RESISTANCE IN MLL LEUKEMIC CELLS, BUT ALSO ILLUSTRATE THAT PREVENTING THE EMERGENCE OF PI-RESISTANT CELLS CONSTITUTES A NOVEL RATIONALE FOR COMBINATION THERAPY WITH PIS AND HDAC INHIBITORS IN MLL LEUKEMIAS. 2020 4 1704 35 DYNAMICS OF MINIMAL RESIDUAL DISEASE IN NEUROBLASTOMA PATIENTS. NEUROBLASTOMA IS A COMMON EXTRACRANIAL SOLID TUMOR OF NEURAL CREST (NC) ORIGIN THAT ACCOUNTS FOR UP TO 15% OF ALL PEDIATRIC CANCER DEATHS. THE DISEASE ARISES FROM A TRANSIENT POPULATION OF NC CELLS THAT UNDERGO AN EPITHELIAL-MESENCHYMAL TRANSITION (EMT) AND GENERATE DIVERSE CELL-TYPES AND TISSUES. PATIENTS WITH NEUROBLASTOMA ARE CHARACTERIZED BY THEIR EXTREME HETEROGENEITY RANGING FROM SPONTANEOUS REGRESSION TO MALIGNANT PROGRESSION. MORE THAN HALF OF NEWLY DIAGNOSED PATIENTS PRESENT HIGHLY METASTATIC TUMORS AND ARE STRATIFIED INTO A HIGH-RISK GROUP WITH DISMAL OUTCOME. AS MANY AS 20% OF HIGH-RISK PATIENTS HAVE RESIDUAL DISEASE THAT IS REFRACTORY OR PROGRESSIVE DURING INDUCTION CHEMOTHERAPY. ALTHOUGH A MAJORITY OF HIGH-RISK PATIENTS ACHIEVE REMISSION, LARGER PART OF THOSE PATIENTS HAS MINIMAL RESIDUAL DISEASE (MRD) THAT CAUSES RELAPSE EVEN AFTER ADDITIONAL CONSOLIDATION THERAPY. MRD IS COMPOSED OF DRUG-RESISTANT TUMOR CELLS AND DYNAMICALLY PRESENTED AS CANCER STEM CELLS (CSCS) IN RESIDUAL TUMORS, CIRCULATING TUMOR CELLS (CTCS) IN PERIPHERAL BLOOD (PB), AND DISSEMINATED TUMOR CELLS (DTCS) IN BONE MARROW (BM) AND OTHER METASTATIC SITES. EMT APPEARS TO BE A KEY MECHANISM FOR CANCER CELLS TO ACQUIRE MRD PHENOTYPES AND MALIGNANT AGGRESSIVENESS. DUE TO THE RESTRICTED AVAILABILITY OF RESIDUAL TUMORS, PB AND BM HAVE BEEN USED TO ISOLATE AND ANALYZE CTCS AND DTCS TO EVALUATE MRD IN CANCER PATIENTS. IN ADDITION, RECENT TECHNICAL ADVANCES MAKE IT POSSIBLE TO USE CIRCULATING TUMOR DNA (CTDNA) SHED FROM TUMOR CELLS INTO PB FOR MRD EVALUATION. BECAUSE MRD CAN BE DETECTED BY TUMOR-SPECIFIC ANTIGENS, GENETIC OR EPIGENETIC CHANGES, AND MRNAS, NUMEROUS ASSAYS USING DIFFERENT METHODS AND SAMPLES HAVE BEEN REPORTED TO DETECT MRD IN CANCER PATIENTS. IN CONTRAST TO THE TUMOR-SPECIFIC GENE-REARRANGEMENT-POSITIVE ACUTE LYMPHOBLASTIC LEUKEMIA (ALL) AND THE ONCOGENIC FUSION-GENE-POSITIVE CHRONIC MYELOGENOUS LEUKEMIA (CML) AND SEVERAL SOLID TUMORS, THE CLINICAL SIGNIFICANCE OF MRD REMAINS TO BE ESTABLISHED IN NEUROBLASTOMA. GIVEN THE EXTREME HETEROGENEITY OF NEUROBLASTOMA, DYNAMICS OF MRD IN NEUROBLASTOMA PATIENTS WILL HOLD A KEY TO THE CLINICAL VALIDATION. IN THIS REVIEW, WE SUMMARIZE THE BIOLOGY AND DETECTION METHODS OF CANCER MRD IN GENERAL AND EVALUATE THE AVAILABLE ASSAYS AND CLINICAL SIGNIFICANCE OF NEUROBLASTOMA MRD TO CLARIFY ITS DYNAMICS IN NEUROBLASTOMA PATIENTS. 2019 5 331 27 ALTERATION IN MITOCHONDRIAL DYNAMICS PROMOTES THE PROINFLAMMATORY RESPONSE OF MICROGLIA AND IS INVOLVED IN CEREBELLAR DYSFUNCTION OF YOUNG AND AGED MICE FOLLOWING LPS EXPOSURE. CEREBELLAR DYSFUNCTION IS IMPLICATED IN IMPAIRED MOTOR COORDINATION AND BALANCE, THUS DISTURBING THE DYNAMICS OF SENSORIMOTOR INTEGRATION. NEUROINFLAMMATION AND AGING COULD BE PROMINENT CONTRIBUTORS TO CEREBELLAR ABERRATION. ADDITIONALLY, CHANGES IN MITOCHONDRIAL DYNAMICS MAY PRECEDE MICROGLIA ACTIVATION IN SEVERAL CHRONIC NEURODEGENERATIVE DISEASES; HOWEVER, THE UNDERLYING MECHANISM REMAINS LARGELY UNKNOWN. HERE USING LPS (1 MG/KG I.P. FOR FOUR CONSECUTIVE DAYS) STIMULATION IN BOTH YOUNG (3 MONTHS OLD) AND AGED (12 MONTHS OLD) MICE, FOLLOWED BY MOLECULAR ANALYSIS ON THE 21ST DAY, WE HAVE EXPLORED THE CORRELATION BETWEEN AGING AND MITOCHONDRIAL DYNAMIC ALTERATION IN THE BACKDROP OF CHRONIC NEUROINFLAMMATION. FOLLOWING LPS STIMULATION, WE OBSERVED MICROGLIA ACTIVATION AND SUBSEQUENT ELEVATION IN PROINFLAMMATORY CYTOKINES (M1; TNF-ALPHA, IFN-GAMMA) WITH NLRP3 ACTIVATION AND A CONCOMITANT REDUCTION IN THE EXPRESSION OF ANTI-INFLAMMATORY MARKERS (M2; YM1, TGF-BETA1) IN THE CEREBELLAR TISSUE OF AGED MICE COMPARED WITH THE YOUNG LPS AND AGED CONTROLS. REMARKABLY, SENESCENCE (P21, P27, P53) AND EPIGENETIC (HDAC2) MARKERS WERE FOUND UPREGULATED IN THE CEREBELLUM TISSUE OF THE AGED LPS GROUP, SUGGESTING THEIR CRUCIAL ROLE IN LPS-INDUCED CEREBELLAR DEFICIT. FURTHER, WE DEMONSTRATED ALTERATION IN THE ANTAGONISTIC FORCES OF MITOCHONDRIAL FUSION AND FISSION WITH INCREASED EXPRESSION OF THE MITOCHONDRIAL FISSION-RELATED GENE [FIS1] AND DECREASED FUSION-RELATED GENES [MFN1 AND MFN2]. WE NOTED INCREASED MTDNA COPY NUMBER, MICROGLIA ACTIVATION, AND INFLAMMATORY RESPONSE OF IL1-BETA AND IFN-GAMMA POST-CHRONIC NEUROINFLAMMATION IN AGED LPS GROUP. OUR RESULTS SUGGEST THAT THE CROSSTALK BETWEEN MITOCHONDRIAL DYNAMICS AND ALTERED MICROGLIAL ACTIVATION PARADIGM IN CHRONIC NEUROINFLAMMATORY CONDITIONS MAY BE THE KEY TO UNDERSTANDING THE CEREBELLAR MOLECULAR MECHANISM. 2023 6 1828 20 EFFECTS OF INHALED TOBACCO SMOKE ON THE PULMONARY TUMOR MICROENVIRONMENT. TOBACCO SMOKE IS A MULTICOMPONENT MIXTURE OF CHEMICAL, ORGANIC, AND INORGANIC COMPOUNDS, AS WELL AS ADDITIVE SUBSTANCES AND RADIOACTIVE MATERIALS. MANY STUDIES HAVE PROVED THE CARCINOGENICITY OF VARIOUS OF THESE COMPOUNDS THROUGH THE INDUCTION OF DNA ADDUCTS, MUTATIONAL POTENTIAL, EPIGENETIC CHANGES, GENE FUSIONS, AND CHROMOSOMAL EVENTS. THE TUMOR MICROENVIRONMENT PLAYS AN IMPORTANT ROLE IN MALIGNANT TUMOR FORMATION AND PROGRESSION THROUGH THE REGULATION OF EXPRESSION OF KEY MOLECULES WHICH MEDIATE THE RECRUITMENT OF IMMUNE CELLS TO THE TUMOR SITE AND SUBSEQUENTLY REGULATE TUMOR GROWTH AND METASTASIS. IN THIS CHAPTER, WE DISCUSS THE EFFECTS OF INHALED TOBACCO SMOKE IN THE TUMOR MICROENVIRONMENT OF THE RESPIRATORY TRACT. THE MECHANISMS UNDERLYING THESE EFFECTS AS WELL AS THEIR LINK WITH TUMOR PROGRESSION ARE ANALYZED. 2020 7 5301 24 PROTEIN PHOSPHATASE 2A CATALYTIC SUBUNIT ALPHA PLAYS A MYD88-DEPENDENT, CENTRAL ROLE IN THE GENE-SPECIFIC REGULATION OF ENDOTOXIN TOLERANCE. MYD88, THE INTRACELLULAR ADAPTOR OF MOST TLRS, MEDIATES EITHER PROINFLAMMATORY OR IMMUNOSUPPRESSIVE SIGNALING THAT CONTRIBUTES TO CHRONIC INFLAMMATION-ASSOCIATED DISEASES. ALTHOUGH GENE-SPECIFIC CHROMATIN MODIFICATIONS REGULATE INFLAMMATION, THE ROLE OF MYD88 SIGNALING IN ESTABLISHING SUCH EPIGENETIC LANDSCAPES UNDER DIFFERENT INFLAMMATORY STATES REMAINS ELUSIVE. USING QUANTITATIVE PROTEOMICS TO ENUMERATE THE INFLAMMATION-PHENOTYPIC CONSTITUENTS OF THE MYD88 INTERACTOME, WE FOUND THAT IN ENDOTOXIN-TOLERANT MACROPHAGES, PROTEIN PHOSPHATASE 2A CATALYTIC SUBUNIT ALPHA (PP2AC) ENHANCES ITS ASSOCIATION WITH MYD88 AND IS CONSTITUTIVELY ACTIVATED. KNOCKDOWN OF PP2AC PREVENTS SUPPRESSION OF PROINFLAMMATORY GENES AND RESISTANCE TO APOPTOSIS. THROUGH SITE-SPECIFIC DEPHOSPHORYLATION, CONSTITUTIVELY ACTIVE PP2AC DISRUPTS THE SIGNAL-PROMOTING TLR4-MYD88 COMPLEX AND BROADLY SUPPRESSES THE ACTIVITIES OF MULTIPLE PROINFLAMMATORY/PROAPOPTOTIC PATHWAYS AS WELL, SHIFTING PROINFLAMMATORY MYD88 SIGNALING TO A PROSURVIVAL MODE. CONSTITUTIVELY ACTIVE PP2AC TRANSLOCATED WITH MYD88 INTO THE NUCLEI OF TOLERANT MACROPHAGES ESTABLISHES THE IMMUNOSUPPRESSIVE PATTERN OF CHROMATIN MODIFICATIONS AND REPRESSES CHROMATIN REMODELING TO SELECTIVELY SILENCE PROINFLAMMATORY GENES, COORDINATING THE MYD88-DEPENDENT INFLAMMATION CONTROL AT BOTH SIGNALING AND EPIGENETIC LEVELS UNDER ENDOTOXIN-TOLERANT CONDITIONS. 2013 8 5477 26 RESTORING THE FUNCTIONAL IMMUNOGENICITY OF CHRONIC LYMPHOCYTIC LEUKEMIA USING EPIGENETIC MODIFIERS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS A MALIGNANCY ARISING FROM IMMUNE CELLS (B-LYMPHOCYTES) ENDOWED WITH INTRINSIC ANTIGEN-PRESENTING CAPABILITIES. SUCH A FUNCTION HOWEVER IS LOST DURING MALIGNANT TRANSFORMATION AND CLL CELLS ARE WELL KNOWN FOR THEIR INABILITY TO PROCESS AND PRESENT ANTIGENS TO THE T-CELL ARM OF THE IMMUNE SYSTEM. INSTEAD, MALIGNANT CLL CELLS ELICIT A VAST ARRAY OF IMMUNE REGULATORY MECHANISMS CONDUCIVE TO T-CELL DYSFUNCTION AND IMMUNOSUPPRESSION. PREVIOUSLY, WE HAVE SHOWN THAT TREATMENT OF CLL CELLS WITH THE DEMETHYLATING AGENT 5-AZA-2'-DEOXYCYTIDINE UNLEASHED TARGET ANTIGEN EXPRESSION. HERE WE SHOW FOR THE FIRST TIME THAT COMBINING TWO EPIGENETIC MODIFIERS, 5-AZA-2'-DEOXYCYTIDINE AND THE HISTONE DEACETYLASE INHIBITOR LAQ824 EFFECTIVELY RESTORES THE IMMUNOGENICITY OF CLL CELL LINES AS WELL AS PRIMARY CELLS OBTAINED FROM CLL PATIENTS. INDEED, SUCH A COMBINATION INDUCES THE EXPRESSION OF NOVEL AND HIGHLY ANTIGENIC CANCER-TESTIS ANTIGENS (CTAS) AND COSTIMULATORY MOLECULES. THESE CHANGES FACILITATE THE FORMATION OF ROBUST SUPRAMOLECULAR ACTIVATION COMPLEXES (SMAC) BETWEEN CLL CELLS AND RESPONDER T-CELLS LEADING TO INTRACELLULAR SIGNALING, LYTIC GRANULE MOBILIZATION, AND POLARIZATION OF FUNCTIONAL AND RELEVANT T-CELL RESPONSES. THIS CASCADE OF T-CELL ACTIVATING EVENTS TRIGGERED BY CLL CELLS WITH RESTORED APC FUNCTION, POINTS TO COMBINED EPIGENETIC MODIFIER TREATMENT AS A POTENTIAL IMMUNOTHERAPEUTIC STRATEGY FOR CLL PATIENTS. 2011 9 1031 29 CIRCULATING TUMOR DNA DETECTION AND ITS APPLICATION STATUS IN GASTRIC CANCER: A NARRATIVE REVIEW. CIRCULATING TUMOR DNA (CTDNA) IS THE SMALL GENOMIC FRAGMENT RELEASED BY TUMOR CELLS INTO THE CIRCULATING SYSTEM, WHICH CARRIES THE GENE VARIATION FEATURES, SUCH AS MUTATION, INSERTION, DELETION, REARRANGEMENT, COPY NUMBER VARIATION (CNV) AND METHYLATION, RENDERING IT AN IMPORTANT BIOMARKER. IT CAN BE USED NOT ONLY TO DIAGNOSE CERTAIN TYPES OF SOLID TUMORS, BUT ALSO TO MONITOR THE THERAPEUTIC RESPONSE AND EXPLORE THE MINIMAL RESIDUAL DISEASE (MRD) AND RESISTANT MUTATION OF TARGETED THERAPY. THEREFORE, CTDNA DETECTION MAY BECOME THE PREFERRED NON-INVASIVE TUMOR SCREENING METHOD. FOR PATIENTS WHO CANNOT RECEIVE FURTHER GENE DETECTION DUE TO INSUFFICIENT OR RESTRICTED SAMPLE COLLECTION WITH THE DEFINED PATHOLOGICAL DIAGNOSIS, CTDNA DETECTION CAN BE CARRIED OUT TO DETERMINE THE GENE MUTATION TYPE, WITH NO NEED FOR REPEATED SAMPLING. GASTRIC CANCER (GC) IS A MALIGNANCY WITH EXTREMELY HIGH MORBIDITY AND MORTALITY, AND ITS GENESIS AND DEVELOPMENT ARE THE CONSEQUENCE OF INTERACTIONS OF MULTIPLE FACTORS, INCLUDING ENVIRONMENT, DIET, HEREDITY, HELICOBACTER PYLORI INFECTION, CHRONIC INFLAMMATORY INFILTRATION, AND PRECANCEROUS LESION. AS THE RESEARCH ON GC MOVES FORWARD, THE EXISTING RESEARCH MAINLY FOCUSES ON GENETIC AND EPIGENETIC CHANGES, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, NON-CODING RNA CHANGES, GENE MUTATION, GENE HETEROZYGOSITY LOSS AND MICROSATELLITE INSTABILITY. THIS PAPER AIMED TO SUMMARIZE THE CONTENTS OF CTDNA DETECTION, ITS APPLICATION STATUS IN GC AND CLINICAL SIGNIFICANCE. 2021 10 5184 23 PREMATURE CHROMOSOME CONDENSATION ASSAY TO STUDY INFLUENCE OF HIGH-LEVEL NATURAL RADIATION ON THE INITIAL DNA DOUBLE STRAND BREAK REPAIR IN HUMAN G(0) LYMPHOCYTES. THE INHERENT CAPACITY OF INDIVIDUALS TO EFFICIENTLY REPAIR IONIZING RADIATION INDUCED DNA DOUBLE STRAND BREAKS (DSBS) MAY BE INHERITED, HOWEVER, IT IS INFLUENCED BY SEVERAL EPIGENETIC AND ENVIRONMENTAL FACTORS. A PILOT STUDY TESTED WHETHER CHRONIC LOW DOSE NATURAL RADIATION EXPOSURE INFLUENCES THE REJOINING OF INITIAL DNA DSBS INDUCED BY A 2 GY GAMMA-IRRADIATION IN 22 INDIVIDUALS FROM HIGH (>1.5 MGY/YEAR) AND NORMAL (