1 6697 167 VARICELLA-ZOSTER VIRUS HUMAN GANGLIONIC LATENCY: A CURRENT SUMMARY. VARICELLA-ZOSTER VIRUS (VZV) IS A UBIQUITOUS HUMAN HERPES VIRUS TYPICALLY ACQUIRED IN CHILDHOOD WHEN IT CAUSES VARICELLA (CHICKENPOX), FOLLOWING WHICH THE VIRUS ESTABLISHES A LATENT INFECTION IN TRIGEMINAL AND DORSAL ROOT GANGLIA THAT LASTS FOR THE LIFE OF THE INDIVIDUAL. VZV SUBSEQUENTLY REACTIVATES, SPONTANEOUSLY OR AFTER SPECIFIC TRIGGERING FACTORS, TO CAUSE HERPES ZOSTER (SHINGLES), WHICH MAY BE COMPLICATED BY POSTHERPETIC NEURALGIA AND SEVERAL OTHER NEUROLOGICAL COMPLICATIONS INCLUDING VASCULOPATHY. OUR UNDERSTANDING OF VZV LATENCY LAGS BEHIND OUR KNOWLEDGE OF HERPES SIMPLEX VIRUS TYPE 1 (HSV-1) LATENCY PRIMARILY DUE TO THE DIFFICULTY IN PROPAGATING THE VIRUS TO HIGH TITERS IN A CELL-FREE STATE, AND THE LACK OF A SUITABLE SMALL-ANIMAL MODEL FOR STUDYING VIRUS LATENCY AND REACTIVATION. IT IS NOW ESTABLISHED BEYOND DOUBT THAT LATENT VZV IS PREDOMINANTLY LOCATED IN HUMAN GANGLIONIC NEURONS. VIRUS GENE TRANSCRIPTION DURING LATENCY IS EPIGENETICALLY REGULATED, AND APPEARS TO BE RESTRICTED TO EXPRESSION OF AT LEAST SIX GENES, WITH EXPRESSION OF GENE 63 BEING THE HALLMARK OF LATENCY. HOWEVER, VIRAL GENE TRANSCRIPTION MAY BE MORE EXTENSIVE THAN PREVIOUSLY THOUGHT. THERE IS ALSO EVIDENCE FOR SEVERAL VZV GENES BEING EXPRESSED AT THE PROTEIN LEVEL, INCLUDING VZV GENE 63-ENCODED PROTEIN, BUT RECENT EVIDENCE SUGGESTS THAT THIS MAY NOT BE A COMMON EVENT. THE NATURE AND EXTENT OF THE CHRONIC INFLAMMATORY RESPONSE IN LATENTLY INFECTED GANGLIA IS ALSO OF CURRENT INTEREST. THERE REMAIN SEVERAL QUESTIONS CONCERNING THE VZV LATENCY PROCESS THAT STILL NEED TO BE RESOLVED UNAMBIGUOUSLY AND IT IS LIKELY THAT THIS WILL REQUIRE THE USE OF NEWLY DEVELOPED MOLECULAR TECHNOLOGIES, SUCH AS GEXPS MULTIPLEX POLYMERASE CHAIN REACTION (PCR) FOR VIRUS TRANSCRIPTIONAL ANALYSIS AND CHIP-SEQ TO STUDY THE EPIGENETIC OF LATENT VIRUS GENOME ( LIU ET AL, 2010 , BMC BIOL 8: 56). 2010 2 40 67 A COMPARISON OF HERPES SIMPLEX VIRUS TYPE 1 AND VARICELLA-ZOSTER VIRUS LATENCY AND REACTIVATION. HERPES SIMPLEX VIRUS TYPE 1 (HSV-1; HUMAN HERPESVIRUS 1) AND VARICELLA-ZOSTER VIRUS (VZV; HUMAN HERPESVIRUS 3) ARE HUMAN NEUROTROPIC ALPHAHERPESVIRUSES THAT CAUSE LIFELONG INFECTIONS IN GANGLIA. FOLLOWING PRIMARY INFECTION AND ESTABLISHMENT OF LATENCY, HSV-1 REACTIVATION TYPICALLY RESULTS IN HERPES LABIALIS (COLD SORES), BUT CAN OCCUR FREQUENTLY ELSEWHERE ON THE BODY AT THE SITE OF PRIMARY INFECTION (E.G. WHITLOW), PARTICULARLY AT THE GENITALS. RARELY, HSV-1 REACTIVATION CAN CAUSE ENCEPHALITIS; HOWEVER, A THIRD OF THE CASES OF HSV-1 ENCEPHALITIS ARE ASSOCIATED WITH HSV-1 PRIMARY INFECTION. PRIMARY VZV INFECTION CAUSES VARICELLA (CHICKENPOX) FOLLOWING WHICH LATENT VIRUS MAY REACTIVATE DECADES LATER TO PRODUCE HERPES ZOSTER (SHINGLES), AS WELL AS AN INCREASINGLY RECOGNIZED NUMBER OF SUBACUTE, ACUTE AND CHRONIC NEUROLOGICAL CONDITIONS. FOLLOWING PRIMARY INFECTION, BOTH VIRUSES ESTABLISH A LATENT INFECTION IN NEURONAL CELLS IN HUMAN PERIPHERAL GANGLIA. HOWEVER, THE DETAILED MECHANISMS OF VIRAL LATENCY AND REACTIVATION HAVE YET TO BE UNRAVELLED. IN BOTH CASES LATENT VIRAL DNA EXISTS IN AN 'END-LESS' STATE WHERE THE ENDS OF THE VIRUS GENOME ARE JOINED TO FORM STRUCTURES CONSISTENT WITH UNIT LENGTH EPISOMES AND CONCATEMERS, FROM WHICH VIRAL GENE TRANSCRIPTION IS RESTRICTED. IN LATENTLY INFECTED GANGLIA, THE MOST ABUNDANTLY DETECTED HSV-1 RNAS ARE THE SPLICED PRODUCTS ORIGINATING FROM THE PRIMARY LATENCY ASSOCIATED TRANSCRIPT (LAT). THIS PRIMARY LAT IS AN 8.3 KB UNSTABLE TRANSCRIPT FROM WHICH TWO STABLE (1.5 AND 2.0 KB) INTRONS ARE SPLICED. TRANSCRIPTS MAPPING TO 12 VZV GENES HAVE BEEN DETECTED IN HUMAN GANGLIA REMOVED AT AUTOPSY; HOWEVER, IT IS DIFFICULT TO ASCRIBE THESE AS TRANSCRIPTS PRESENT DURING LATENT INFECTION AS EARLY-STAGE VIRUS REACTIVATION MAY HAVE TRANSPIRED IN THE POST-MORTEM TIME PERIOD IN THE GANGLIA. NONETHELESS, LOW-LEVEL TRANSCRIPTION OF VZV ORF63 HAS BEEN REPEATEDLY DETECTED IN MULTIPLE GANGLIA REMOVED AS CLOSE TO DEATH AS POSSIBLE. THERE IS INCREASING EVIDENCE THAT HSV-1 AND VZV LATENCY IS EPIGENETICALLY REGULATED. IN VITRO MODELS THAT PERMIT PATHWAY ANALYSIS AND IDENTIFICATION OF BOTH EPIGENETIC MODULATIONS AND GLOBAL TRANSCRIPTIONAL MECHANISMS OF HSV-1 AND VZV LATENCY HOLD MUCH PROMISE FOR OUR FUTURE UNDERSTANDING IN THIS COMPLEX AREA. THIS REVIEW SUMMARIZES THE MOLECULAR BIOLOGY OF HSV-1 AND VZV LATENCY AND REACTIVATION, AND ALSO PRESENTS FUTURE DIRECTIONS FOR STUDY. 2015 3 3280 36 HERPES ZOSTER OPHTHALMICUS FOLLOWING ONABOTULINUMTOXINA ADMINISTRATION FOR CHRONIC MIGRAINE: A CASE REPORT AND LITERATURE REVIEW. BACKGROUND: THERE IS A GROWING BODY OF LITERATURE DOCUMENTING LOCAL HERPES ZOSTER OUTBREAK FOLLOWING PROCEDURES. THE MECHANISM UNDERLYING THESE OUTBREAKS REMAINS ELUSIVE. WE PRESENT A CASE OF ZOSTER FOLLOWING ONABOTULINUMTOXINA (BTX) FOR MIGRAINE AND A LITERATURE REVIEW. METHODS: CHART AND LITERATURE REVIEW. CASE: A 72-YEAR-OLD WOMAN WITH CHRONIC MIGRAINE RECEIVED BTX INJECTIONS FOR 3 YEARS WITHOUT INCIDENT. SHE HAD A HISTORY OF THORACIC ZOSTER WITH SUBSEQUENT POST-HERPETIC NEURALGIA. IN AUGUST 2013, 48 HOURS AFTER RECEIVING BTX INJECTIONS, SHE DEVELOPED A PAINFUL RASH IN THE RIGHT V1 DISTRIBUTION CONSISTENT WITH HERPES ZOSTER OPHTHALMICUS. ONE WEEK LATER THE RASH HAD RESOLVED WITHOUT TREATMENT. LITERATURE REVIEW: WE IDENTIFIED 65 (INCLUDING 2 FROM JUEL-JENSON) CASES OF ZOSTER REACTIVATION FOLLOWING MINOR PROCEDURES. THESE CASES TEND TO BE IN YOUNG PATIENTS WITHOUT SPECIFIC RISK FACTORS. OUTBREAKS CHARACTERISTICALLY OCCUR AT THE LEVEL OF EXPOSURE TO LOCAL TRAUMA. DISCUSSION: OUR REVIEW SUGGESTS THAT LOCAL TRAUMA, REGARDLESS OF THE NATURE OF STIMULI, MAY BE SUFFICIENT FOR ZOSTER REACTIVATION. WE HYPOTHESIZE THAT THE STRESSORS IN THESE REPORTED CASES EXERT A LOCAL EPIGENETIC INFLUENCE ON VIRAL TRANSCRIPTION, ALLOWING FOR VIRAL REACTIVATION. CONCLUSION: ZOSTER IS A POTENTIAL COMPLICATION OF BTX ADMINISTRATION FOR CHRONIC MIGRAINE IN ADULTS. PHYSICIAN AWARENESS CAN REDUCE THE SIGNIFICANT MORBIDITY ASSOCIATED WITH THIS DISEASE. 2015 4 6044 40 THE COMPLEX BIOLOGY OF HUMAN CYTOMEGALOVIRUS LATENCY. WHILE MANY VIRAL INFECTIONS ARE LIMITED AND EVENTUALLY RESOLVED BY THE HOST IMMUNE RESPONSE OR BY DEATH OF THE HOST, OTHER VIRUSES ESTABLISH LONG-TERM RELATIONSHIPS WITH THE HOST BY WAY OF A PERSISTENT INFECTION, THAT RANGE FROM CHRONIC VIRUSES THAT MAY BE EVENTUALLY CLEARED TO THOSE THAT ESTABLISH LIFE-LONG PERSISTENT OR LATENT INFECTION. VIRUSES INFECTING HOSTS FROM BACTERIA TO HUMANS ESTABLISH QUIESCENT INFECTIONS THAT MUST BE REACTIVATED TO PRODUCE PROGENY. FOR MAMMALIAN VIRUSES, MOST NOTABLY HERPESVIRUSES, THIS QUIESCENT MAINTENANCE OF VIRAL GENOMES IN THE ABSENCE OF VIRUS REPLICATION IS REFERRED TO AS LATENCY. THE LATENT STRATEGY ALLOWS THE VIRUS TO PERSIST QUIESCENTLY WITHIN A SINGLE HOST UNTIL CONDITIONS INDICATE A NEED TO REACTIVATE TO REACH A NEW HOST OR, TO RE-SEED A RESERVOIR WITHIN THE HOST. HERE, I REVIEW COMMON THEMES IN VIRAL STRATEGIES TO REGULATE THE LATENT CYCLE AND REACTIVATE FROM IT RANGING FROM BACTERIOPHAGE TO HERPESVIRUSES WITH A FOCUS ON HUMAN CYTOMEGALOVIRUS (HCMV). THEMES CENTRAL TO HERPESVIRUS LATENCY INCLUDE, EPIGENETIC REPRESSION OF VIRAL GENE EXPRESSION AND MECHANISMS TO REGULATE HOST SIGNALING AND SURVIVAL. CRITICAL TO THE SUCCESS OF A LATENT PROGRAM ARE MECHANISMS BY WHICH THE VIRUS CAN "SENSE" FLUCTUATIONS IN HOST BIOLOGY (WITHIN THE HOST) OR ENVIRONMENT (OUTSIDE THE HOST) AND MAKE APPROPRIATE "DECISIONS" TO MAINTAIN LATENCY OR RE-INITIATE THE REPLICATIVE PROGRAM. THE SIGNALS OR ENVIRONMENTS THAT INDICATE THE ESTABLISHMENT OF A LATENT STATE, THE VERY NATURE OF THE LATENT STATE, AS WELL AS THE SIGNALS DRIVING REACTIVATION HAVE BEEN TOPICS OF INTENSE STUDY FROM BACTERIOPHAGE TO HUMAN VIRUSES, AS THESE QUESTIONS ENCOMPASS THE HEIGHT OF COMPLEXITY IN VIRUS-HOST INTERACTIONS-WHERE THE HOST AND THE VIRUS COEXIST. 2022 5 1057 33 CLINICAL MANIFESTATIONS AND EPIGENETIC REGULATION OF ORAL HERPESVIRUS INFECTIONS. THE ORAL CAVITY IS OFTEN THE FIRST SITE WHERE VIRUSES INTERACT WITH THE HUMAN BODY. THE ORAL EPITHELIUM IS A MAJOR SITE OF VIRAL ENTRY, REPLICATION AND SPREAD TO OTHER CELL TYPES, WHERE CHRONIC INFECTION CAN BE ESTABLISHED. IN ADDITION, SALIVA HAS BEEN SHOWN AS A PRIMARY ROUTE OF PERSON-TO-PERSON TRANSMISSION FOR MANY VIRUSES. FROM A CLINICAL PERSPECTIVE, VIRAL INFECTION CAN LEAD TO SEVERAL ORAL MANIFESTATIONS, RANGING FROM COMMON INTRAORAL LESIONS TO TUMORS. DESPITE THE CLINICAL AND BIOLOGICAL RELEVANCE OF INITIAL ORAL INFECTION, LITTLE IS KNOWN ABOUT THE MECHANISM OF REGULATION OF THE VIRAL LIFE CYCLE IN THE ORAL CAVITY. SEVERAL VIRUSES UTILIZE HOST EPIGENETIC MACHINERY TO PROMOTE THEIR OWN LIFE CYCLE. IMPORTANTLY, VIRAL HIJACKING OF HOST CHROMATIN-MODIFYING ENZYMES CAN ALSO LEAD TO THE DYSREGULATION OF HOST FACTORS AND IN THE CASE OF ONCOGENIC VIRUSES MAY ULTIMATELY PLAY A ROLE IN PROMOTING TUMORIGENESIS. GIVEN THE KNOWN ROLES OF EPIGENETIC REGULATION OF VIRAL INFECTION, EPIGENETIC-TARGETED ANTIVIRAL THERAPY HAS BEEN RECENTLY EXPLORED AS A THERAPEUTIC OPTION FOR CHRONIC VIRAL INFECTION. IN THIS REVIEW, WE HIGHLIGHT THREE HERPESVIRUSES WITH KNOWN ROLES IN ORAL INFECTION, INCLUDING HERPES SIMPLEX VIRUS TYPE 1, EPSTEIN-BARR VIRUS AND KAPOSI'S SARCOMA-ASSOCIATED HERPESVIRUS. WE FOCUS ON THE RESPECTIVE ORAL CLINICAL MANIFESTATIONS OF THESE VIRUSES AND THEIR EPIGENETIC REGULATION, WITH A SPECIFIC EMPHASIS ON THE VIRAL LIFE CYCLE IN THE ORAL EPITHELIUM. 2021 6 2115 30 EPIGENETIC HETEROGENEITY IN HIV-1 LATENCY ESTABLISHMENT. DESPITE PROLONGED ANTIRETROVIRAL THERAPY, HIV-1 PERSISTS AS TRANSCRIPTIONALLY INACTIVE PROVIRUSES. THE HIV-1 LATENCY REMAINS A PRINCIPAL OBSTACLE IN CURING AIDS. IT IS IMPORTANT TO UNDERSTAND MECHANISMS BY WHICH HIV-1 LATENCY IS ESTABLISHED TO MAKE THE LATENT RESERVOIR SMALLER. WE PRESENT A MOLECULAR CHARACTERIZATION OF DISTINCT POPULATIONS AT AN EARLY PHASE OF INFECTION. WE DEVELOPED AN ORIGINAL DUAL-COLOR REPORTER VIRUS TO MONITOR LTR KINETICS FROM ESTABLISHMENT TO MAINTENANCE STAGE. WE FOUND THAT THERE ARE TWO WAYS OF LATENCY ESTABLISHMENT I.E., BY IMMEDIATE SILENCING AND SLOW INACTIVATION FROM ACTIVE INFECTION. HISTONE COVALENT MODIFICATIONS, PARTICULARLY POLYCOMB REPRESSIVE COMPLEX 2 (PRC2)-MEDIATED H3K27 TRIMETHYLATION, APPEARED TO DOMINATE VIRAL TRANSCRIPTION AT THE EARLY PHASE. PRC2 ALSO CONTRIBUTES TO TIME-DEPENDENT LTR DORMANCY IN THE CHRONIC PHASE OF THE INFECTION. SIGNIFICANT DIFFERENCES IN SENSITIVITY AGAINST SEVERAL STIMULI WERE OBSERVED BETWEEN THESE TWO DISTINCT POPULATIONS. THESE RESULTS WILL EXPAND OUR UNDERSTANDING OF HETEROGENEOUS ESTABLISHMENT OF HIV-1 LATENCY POPULATIONS. 2015 7 1006 28 CHRONIC VIRAL INFECTION AND PRIMARY CENTRAL NERVOUS SYSTEM MALIGNANCY. PRIMARY CENTRAL NERVOUS SYSTEM (CNS) TUMORS CAUSE SIGNIFICANT MORBIDITY AND MORTALITY IN BOTH ADULTS AND CHILDREN. WHILE SOME OF THE GENETIC AND MOLECULAR MECHANISMS OF NEURO-ONCOGENESIS ARE KNOWN, MUCH LESS IS KNOWN ABOUT POSSIBLE EPIGENETIC CONTRIBUTIONS TO DISEASE PATHOPHYSIOLOGY. OVER THE LAST SEVERAL DECADES, CHRONIC VIRAL INFECTIONS HAVE BEEN ASSOCIATED WITH A NUMBER OF HUMAN MALIGNANCIES. IN PRIMARY CNS MALIGNANCIES, TWO FAMILIES OF VIRUSES, NAMELY POLYOMAVIRUS AND HERPESVIRUS, HAVE BEEN DETECTED WITH VARIED FREQUENCIES IN A NUMBER OF PEDIATRIC AND ADULT HISTOLOGICAL TUMOR SUBTYPES. HOWEVER, ESTABLISHING A LINK BETWEEN CHRONIC VIRAL INFECTION AND PRIMARY CNS MALIGNANCY HAS BEEN AN AREA OF CONSIDERABLE CONTROVERSY, DUE IN PART TO VARIATIONS IN DETECTION FREQUENCIES AND METHODOLOGIES USED AMONG RESEARCHERS. SINCE A LATENT VIRAL NEUROTROPISM CAN BE SEEN WITH A VARIETY OF VIRUSES AND A WIDESPREAD SEROPOSITIVITY EXISTS AMONG THE POPULATION, IT HAS BEEN DIFFICULT TO ESTABLISH AN ASSOCIATION BETWEEN VIRAL INFECTION AND CNS MALIGNANCY BASED ON EPIDEMIOLOGY ALONE. WHILE DIRECT EVIDENCE OF A ROLE OF VIRUSES IN NEURO-ONCOGENESIS IN HUMANS IS LACKING, A MORE PLAUSIBLE HYPOTHESIS OF NEURO-ONCOMODULATION HAS BEEN PROPOSED. THE OVERALL GOALS OF THIS REVIEW ARE TO SUMMARIZE THE MANY HUMAN INVESTIGATIONS THAT HAVE STUDIED VIRAL INFECTION IN PRIMARY CNS TUMORS, DISCUSS POTENTIAL NEURO-ONCOMODULATORY MECHANISMS OF VIRAL-ASSOCIATED CNS DISEASE AND PROPOSE FUTURE RESEARCH DIRECTIONS TO ESTABLISH A MORE FIRM ASSOCIATION BETWEEN CHRONIC VIRAL INFECTIONS AND PRIMARY CNS MALIGNANCIES. 2010 8 2073 31 EPIGENETIC CROSSTALK IN CHRONIC INFECTION WITH HIV-1. HUMAN IMMUNODEFICIENCY VIRUS 1 (HIV-1) REPLICATES THROUGH THE INTEGRATION OF ITS VIRAL DNA INTO THE GENOME OF HUMAN IMMUNE TARGET CELLS. CHRONICALLY INFECTED INDIVIDUALS THUS CARRY A GENOMIC BURDEN OF VIRUS-DERIVED SEQUENCES THAT PERSISTS THROUGH ANTIRETROVIRAL THERAPY. THIS BURDEN CONSISTS OF A SMALL FRACTION OF INTACT, BUT TRANSCRIPTIONALLY SILENCED, I.E. LATENT, VIRAL GENOMES AND A DOMINANT FRACTION OF DEFECTIVE SEQUENCES. REMARKABLY, ALL VIRAL-DERIVED SEQUENCES ARE SUBJECT TO INTERACTION WITH HOST CELLULAR PHYSIOLOGY AT VARIOUS LEVELS. IN THIS REVIEW, WE FOCUS ON EPIGENETIC ASPECTS OF THIS INTERACTION. WE PROVIDE A COMPREHENSIVE OVERVIEW OF HOW EPIGENETIC MECHANISMS CONTRIBUTE TO ESTABLISHMENT AND MAINTENANCE OF HIV-1 GENE REPRESSION DURING LATENCY. WE FURTHERMORE SUMMARIZE FINDINGS INDICATING THAT HIV-1 INFECTION LEADS TO CHANGES IN THE EPIGENOME OF TARGET AND BYSTANDER IMMUNE CELLS. FINALLY, WE DISCUSS HOW AN IMPROVED UNDERSTANDING OF EPIGENETIC FEATURES AND MECHANISMS INVOLVED IN HIV-1 INFECTION COULD BE EXPLOITED FOR CLINICAL USE. 2020 9 6706 29 VIRAL GENE PRODUCTS ACTIVELY PROMOTE LATENT INFECTION BY EPIGENETIC SILENCING MECHANISMS. MANY VIRUSES UNDERGO AN ACUTE INFECTION IN THE HOST ORGANISM AND THEN ARE CLEARED BY THE ENSUING HOST IMMUNE RESPONSE, BUT OTHER VIRUSES ESTABLISH A PERSISTENT INFECTION INVOLVING A LATENT INFECTION OR A CHRONIC INFECTION. LATENT INFECTION BY THE HERPESVIRUSES OR HUMAN IMMUNODEFICIENCY VIRUS INVOLVES EPIGENETIC SILENCING OF THE DNA GENOME OR PROVIRAL GENOME, RESPECTIVELY. LATENT INFECTION WAS PREVIOUSLY THOUGHT TO BE A DEFAULT PATHWAY RESULTING FROM INFECTION OF A NONPERMISSIVE CELL, BUT RECENT STUDIES HAVE SHOWN THAT VIRAL GENE PRODUCTS CAN PROMOTE EPIGENETIC SILENCING AND LATENT INFECTION. THIS REVIEW WILL SUMMARIZE THE VIRAL GENE PRODUCTS THAT HAVE BEEN SHOWN TO PROMOTE EPIGENETIC SILENCING OF THE GENOMES AND THEIR POTENTIAL FOR THERAPEUTICS TO TARGET THESE VIRAL GENE PRODUCTS AND DISRUPT OR LOCK IN LATENT INFECTION. 2017 10 3379 33 HIV LATENCY AND THE NONCODING RNA THERAPEUTIC LANDSCAPE. THE HUMAN IMMUNODEFICIENCY VIRUS (HIV) BELONGS TO THE SUBFAMILY OF LENTIVIRUSES THAT ARE CHARACTERIZED BY LONG INCUBATION PERIODS AND CHRONIC, PERSISTENT INFECTION. THE VIRUS INTEGRATES INTO THE GENOME OF INFECTED CD4+ CELLS AND, IN A SUBPOPULATION OF CELLS, ADOPTS A TRANSCRIPTIONALLY SILENT STATE, A PROCESS REFERRED TO A VIRAL LATENCY. THIS PROPERTY MAKES IT EXCEEDINGLY DIFFICULT TO THERAPEUTICALLY TARGET THE VIRUS AND ERADICATE INFECTION. IF LEFT UNTREATED, THE INEXORABLE DEMISE OF THE INFECTED INDIVIDUAL'S IMMUNE SYSTEM ENSUES, A CAUSAL RESULT OF ACQUIRED IMMUNODEFICIENCY SYNDROME (AIDS). LATENTLY INFECTED CELLS PROVIDE A RESERVOIR THAT MAINTAINS VIRAL INFECTION INDEFINITELY. IN THIS CHAPTER WE EXPLORE THE ROLE OF NONCODING RNAS IN HIV INFECTION AND IN THE ESTABLISHMENT AND MAINTENANCE OF VIRAL LATENCY. BOTH SHORT AND LONG NONCODING RNAS ARE ENDOGENOUS MODULATORS OF EPIGENETIC REGULATION IN HUMAN CELLS AND PLAY AN ACTIVE ROLE IN GENE EXPRESSION. LASTLY, WE EXPLORE THERAPEUTIC MODALITIES BASED ON EXPRESSED RNAS THAT ARE CAPABLE OF COUNTERING INFECTION, TRANSCRIPTIONALLY REGULATING THE VIRUS, AND SUPPRESSING OR ACTIVATING THE LATENT STATE. 2015 11 3938 30 LNC(ING)RNAS TO THE "SHOCK AND KILL" STRATEGY FOR HIV-1 CURE. THE ADVENT OF ANTIRETROVIRAL THERAPY ALMOST 25 YEARS AGO HAS TRANSFORMED HIV-1 INFECTION INTO A MANAGEABLE CHRONIC CONDITION, ALBEIT STILL INCURABLE. THE INABILITY OF THE TREATMENT REGIMEN TO ELIMINATE LATENTLY INFECTED CELLS THAT HARBOR THE VIRUS IN AN EPIGENETICALLY SILENT STATE POSES A MAJOR HURDLE. CURRENT CURE APPROACHES ARE FOCUSED ON A "SHOCK AND KILL" STRATEGY THAT USES LATENCY-REVERSING AGENTS TO CHEMICALLY REVERSE THE PROVIRAL QUIESCENCE IN LATENTLY INFECTED CELLS, FOLLOWED BY IMMUNE-MEDIATED CLEARANCE OF REACTIVATED CELLS. TO DATE, HUNDREDS OF COMPOUNDS HAVE BEEN INVESTIGATED FOR VIRAL REACTIVATION, YET NONE HAS RESULTED IN A FUNCTIONAL CURE. THE INSUFFICIENCY OF THESE LATENCY-REVERSING AGENTS (LRAS) ALONE INDICATES A CRITICAL NEED FOR ADDITIONAL, ALTERNATE APPROACHES SUCH AS GENETIC MANIPULATION. LONG NON-CODING RNAS (LNCRNAS) ARE AN EMERGING CLASS OF REGULATORY RNAS WITH FUNCTIONAL ROLES IN MANY CELLULAR PROCESSES, INCLUDING EPIGENETIC MODULATION. A NUMBER OF LNCRNAS HAVE ALREADY BEEN IMPLICATED TO PLAY IMPORTANT ROLES IN HIV-1 LATENCY AND, AS SUCH, PHARMACOLOGICAL MODULATION OF LNCRNAS CONSTITUTES A RATIONAL ALTERNATIVE APPROACH IN HIV-1 CURE RESEARCH. IN THIS REVIEW, WE DISCUSS THE CURRENT STATE OF KNOWLEDGE OF THE ROLE OF LNCRNAS IN HIV-1 INFECTION AND EXPLORE THE SCOPE FOR A LNCRNA-MEDIATED GENETIC APPROACH WITHIN THE SHOCK AND KILL STRATEGY OF HIV-1 CURE. 2021 12 3380 38 HIV-1 INFECTION OF GENETICALLY ENGINEERED IPSC-DERIVED CENTRAL NERVOUS SYSTEM-ENGRAFTED MICROGLIA IN A HUMANIZED MOUSE MODEL. THE CENTRAL NERVOUS SYSTEM (CNS) IS A MAJOR HUMAN IMMUNODEFICIENCY VIRUS TYPE 1 RESERVOIR. MICROGLIA ARE THE PRIMARY TARGET CELL OF HIV-1 INFECTION IN THE CNS. CURRENT MODELS HAVE NOT ALLOWED THE PRECISE MOLECULAR PATHWAYS OF ACUTE AND CHRONIC CNS MICROGLIAL INFECTION TO BE TESTED WITH IN VIVO GENETIC METHODS. HERE, WE DESCRIBE A NOVEL HUMANIZED MOUSE MODEL UTILIZING HUMAN-INDUCED PLURIPOTENT STEM CELL-DERIVED MICROGLIA TO XENOGRAFT INTO MURINE HOSTS. THESE MICE ARE ADDITIONALLY ENGRAFTED WITH HUMAN PERIPHERAL BLOOD MONONUCLEAR CELLS THAT SERVED AS A MEDIUM TO ESTABLISH A PERIPHERAL INFECTION THAT THEN SPREAD TO THE CNS MICROGLIA XENOGRAFT, MODELING A TRANS-BLOOD-BRAIN BARRIER ROUTE OF ACUTE CNS HIV-1 INFECTION WITH HUMAN TARGET CELLS. THE APPROACH IS COMPATIBLE WITH IPSC GENETIC ENGINEERING, INCLUDING INSERTING TARGETED TRANSGENIC REPORTER CASSETTES TO TRACK THE XENOGRAFTED HUMAN CELLS, ENABLING THE TESTING OF NOVEL TREATMENT AND VIRAL TRACKING STRATEGIES IN A COMPARATIVELY SIMPLE AND COST-EFFECTIVE WAY VIVO MODEL FOR NEUROHIV. IMPORTANCE: OUR MOUSE MODEL IS A POWERFUL TOOL FOR INVESTIGATING THE GENETIC MECHANISMS GOVERNING CNS HIV-1 INFECTION AND LATENCY IN THE CNS AT A SINGLE-CELL LEVEL. A MAJOR ADVANTAGE OF OUR MODEL IS THAT IT USES IPSC-DERIVED MICROGLIA, WHICH ENABLES HUMAN GENETICS, INCLUDING GENE FUNCTION AND THERAPEUTIC GENE MANIPULATION, TO BE EXPLORED IN VIVO , WHICH IS MORE CHALLENGING TO STUDY WITH CURRENT HEMATOPOIETIC STEM CELL-BASED MODELS FOR NEUROHIV. OUR TRANSGENIC TRACING OF XENOGRAFTED HUMAN CELLS WILL PROVIDE A QUANTITATIVE MEDIUM TO DEVELOP NEW MOLECULAR AND EPIGENETIC STRATEGIES FOR REDUCING THE HIV-1 LATENT RESERVOIR AND TO TEST THE IMPACT OF THERAPEUTIC INFLAMMATION-TARGETING DRUG INTERVENTIONS ON CNS HIV-1 LATENCY. 2023 13 5618 33 SARS-COV-2 INTERACTION WITH HUMAN DNA METHYL TRANSFERASE 1: A POTENTIAL RISK FOR INCREASING THE INCIDENCE OF LATER CHRONIC DISEASES IN THE SURVIVED PATIENTS. CURRENTLY, THE COVID-19 PANDEMIC IS THE MOST DISCUSSED SUBJECT IN MEDICAL RESEARCHES WORLDWIDE. AS THE KNOWLEDGE IS EXPANDED ABOUT THE DISEASE, MORE HYPOTHESES BECOME CREATED. A RECENT STUDY ON THE VIRAL PROTEIN INTERACTION MAP REVEALED THAT SARS-COV-2 OPEN READING FRAME 8 (ORF8) INTERACTS WITH HUMAN DNA METHYL TRANSFERASE1 (DNMT1), AN ACTIVE EPIGENETIC AGENT IN DNA METHYLATION. MOREOVER, DNMT1 IS A CONTRIBUTOR TO A VARIETY OF CHRONIC DISEASES WHICH COULD CAUSE SOME EPIGENETIC DYSREGULATION IN INFECTED CELLS, ESPECIALLY LEUKOCYTES, PANCREATIC BETA, AND ENDOTHELIAL CELLS. REGARDING THE FACT THAT EPIGENETIC ALTERATIONS HAVE A PARTIAL, BUT NOT COMPLETELY REVERSIBLE PHENOMENA, IT RAISES THE QUESTION THAT IF THIS INTERACTION MAY CAUSE LONG-TERM COMPLICATIONS SUCH AS DIABETES, ATHEROSCLEROSIS, CANCER, AND AUTOIMMUNE DISEASES. ACCORDINGLY, LONG FOLLOW-UP STUDIES ON THE RECOVERED PATIENTS FROM COVID-19 ARE RECOMMENDED. 2022 14 1010 28 CHRONICALLY ELEVATED PROLIFERATION AS A RISK FACTOR FOR NEOPLASIA. CHRONIC DISEASE CONDITIONS THAT ARE ASSOCIATED WITH ELEVATED PROLIFERATION ARE WELL ESTABLISHED AS RISK FACTORS FOR CANCER DEVELOPMENT. THESE MAY BE DUE TO VIRUSES (FOR EXAMPLE, IN THE CASE OF HEPATITIS AND LIVER CANCER), BACTERIAL INFECTIONS, PARASITE INFESTATION OR PHYSICAL TRAUMA. IN ADDITION TO THESE EXOGENOUS AGENTS THERE ARE ALSO METABOLIC ABNORMALITIES THAT CAN CONTRIBUTE, CAUSED BY GENETIC OR EPIGENETIC INFLUENCE. IN THE LATTER CASE, AN INCREASE IN SERUM LEVELS OF THE HORMONES OESTROGEN, TESTOSTERONE AND INSULIN MAY BE OF SPECIAL IMPORTANCE. THE PRESENT REVIEW CONCENTRATES ATTENTION ON FACTORS THAT INDUCE ELEVATED CELL TURNOVER AND FOR WHICH THERE IS EPIDEMIOLOGICAL AND/OR EXPERIMENTAL EVIDENCE OF A LINK WITH NEOPLASIA, WITH PARTICULAR STRESS ON THE INDIVIDUAL ORGAN OR TISSUE LEVEL. 1998 15 2507 30 EPIGENETICS AND OBESITY: THE DEVIL IS IN THE DETAILS. OBESITY IS A COMPLEX DISEASE WITH MULTIPLE WELL-DEFINED RISK FACTORS. NEVERTHELESS, SUSCEPTIBILITY TO OBESITY AND ITS SEQUELAE WITHIN OBESOGENIC ENVIRONMENTS VARIES GREATLY FROM ONE PERSON TO THE NEXT, SUGGESTING A ROLE FOR GENE X ENVIRONMENT INTERACTIONS IN THE ETIOLOGY OF THE DISORDER. EPIGENETIC REGULATION OF THE HUMAN GENOME PROVIDES A PUTATIVE MECHANISM BY WHICH SPECIFIC ENVIRONMENTAL EXPOSURES CONVEY RISK FOR OBESITY AND OTHER HUMAN DISEASES AND IS ONE POSSIBLE MECHANISM THAT UNDERLIES THE GENE X ENVIRONMENT/TREATMENT INTERACTIONS OBSERVED IN EPIDEMIOLOGICAL STUDIES AND CLINICAL TRIALS. A STUDY PUBLISHED IN BMC MEDICINE THIS MONTH BY WANG ET AL. REPORTS ON AN EXAMINATION OF DNA METHYLATION IN PERIPHERAL BLOOD LEUKOCYTES OF LEAN AND OBESE ADOLESCENTS, COMPARING METHYLATION PATTERNS BETWEEN THE TWO GROUPS. THE AUTHORS IDENTIFIED TWO GENES THAT WERE DIFFERENTIALLY METHYLATED, BOTH OF WHICH HAVE ROLES IN IMMUNE FUNCTION. HERE WE OVERVIEW THE FINDINGS FROM THIS STUDY IN THE CONTEXT OF THOSE EMERGING FROM OTHER RECENT GENETIC AND EPIGENETIC STUDIES, DISCUSS THE STRENGTHS AND WEAKNESSES OF THE STUDY AND SPECULATE ON THE FUTURE OF EPIGENETICS IN CHRONIC DISEASE RESEARCH. 2010 16 4429 29 MOLECULAR BIOLOGY AS A TOOL FOR THE TREATMENT OF CANCER. CANCER IS A GENETIC DISEASE CHARACTERIZED BY UNCONTROLLED CELL GROWTH AND METASTASIS. CANCER CAN HAVE A NUMBER OF CAUSES, SUCH THE ACTIVATION OF ONCOGENES, THE INACTIVATION OF TUMOR-SUPPRESSING GENES, MUTAGENESIS PROVOKED BY EXTERNAL FACTORS, AND EPIGENETIC MODIFICATIONS. THE DEVELOPMENT OF DIAGNOSTIC TOOLS AND TREATMENTS USING A MOLECULAR BIOLOGICAL APPROACH PERMITS THE USE OF SENSITIVE, LOW-COST, NONINVASIVE TESTS FOR CANCER PATIENTS. BIOMARKERS CAN BE USED TO PROVIDE RAPID, PERSONALIZED ONCOLOGY, IN PARTICULAR THE MOLECULAR DIAGNOSIS OF CHRONIC MYELOID LEUKEMIA, AND GASTRIC, COLON, AND BREAST CANCERS. MOLECULAR TESTS BASED ON DNA METHYLATION CAN ALSO BE USED TO DIRECT TREATMENTS OR EVALUATE THE TOXIC EFFECTS OF CHEMOTHERAPY. THE ADEQUATE DIAGNOSIS, PROGNOSIS, AND PREDICTION OF THE RESPONSE OF CANCER PATIENTS TO TREATMENT ARE ESSENTIAL TO ENSURE THE MOST EFFECTIVE THERAPY, REDUCE THE DAMAGING EFFECTS OF TREATMENT, AND DIRECT THE THERAPY TO SPECIFIC TARGETS, AND IN THIS CONTEXT, MOLECULAR BIOLOGY HAS BECOME INCREASINGLY IMPORTANT IN ONCOLOGY. IN THIS BRIEF REVIEW, WE WILL DEMONSTRATE THE FUNDAMENTAL IMPORTANCE OF MOLECULAR BIOLOGY FOR THE TREATMENT OF THREE TYPES OF CANCER-CHRONIC MYELOID LEUKEMIA, HEREDITARY DIFFUSE GASTRIC CANCER, AND ASTROCYTOMAS (SPORADIC TUMORS OF THE CENTRAL NERVOUS SYSTEM). IN EACH OF THESE THREE MODELS, DISTINCT BIOLOGICAL MECHANISMS ARE INVOLVED IN THE TRANSFORMATION OF THE CELLS, BUT IN ALL CASES, MOLECULAR BIOLOGY IS FUNDAMENTAL TO THE DEVELOPMENT OF PERSONALIZED ANALYSES FOR EACH PATIENT AND EACH TYPE OF NEOPLASIA, AND TO GUARANTEE THE SUCCESS OF THE TREATMENT. 2018 17 6449 44 THERAPEUTIC TARGETING OF TELOMERASE. TELOMERE LENGTH AND CELL FUNCTION CAN BE PRESERVED BY THE HUMAN REVERSE TRANSCRIPTASE TELOMERASE (HTERT), WHICH SYNTHESIZES THE NEW TELOMERIC DNA FROM A RNA TEMPLATE, BUT IS NORMALLY RESTRICTED TO CELLS NEEDING A HIGH PROLIFERATIVE CAPACITY, SUCH AS STEM CELLS. CONSEQUENTLY, TELOMERASE-BASED THERAPIES TO ELONGATE SHORT TELOMERES ARE DEVELOPED, SOME OF WHICH HAVE SUCCESSFULLY REACHED THE STAGE I IN CLINICAL TRIALS. TELOMERASE IS ALSO PERMISSIVE FOR TUMORIGENESIS AND 90% OF ALL MALIGNANT TUMORS USE TELOMERASE TO OBTAIN IMMORTALITY. THUS, REVERSAL OF TELOMERASE UPREGULATION IN TUMOR CELLS IS A POTENTIAL STRATEGY TO TREAT CANCER. NATURAL AND SMALL-MOLECULE TELOMERASE INHIBITORS, IMMUNOTHERAPEUTIC APPROACHES, OLIGONUCLEOTIDE INHIBITORS, AND TELOMERASE-DIRECTED GENE THERAPY ARE USEFUL TREATMENT STRATEGIES. TELOMERASE IS MORE WIDELY EXPRESSED THAN ANY OTHER TUMOR MARKER. THE LOW EXPRESSION IN NORMAL TISSUES, TOGETHER WITH THE LONGER TELOMERES IN NORMAL STEM CELLS VERSUS CANCER CELLS, PROVIDES SOME DEGREE OF SPECIFICITY WITH LOW RISK OF TOXICITY. HOWEVER, LONG TERM TELOMERASE INHIBITION MAY ELICIT NEGATIVE EFFECTS IN HIGHLY-PROLIFERATIVE CELLS WHICH NEED TELOMERASE FOR SURVIVAL, AND IT MAY INTERFERE WITH TELOMERE-INDEPENDENT PHYSIOLOGICAL FUNCTIONS. MOREOVER, ONLY A FEW HTERT MOLECULES ARE REQUIRED TO OVERCOME SENESCENCE IN CANCER CELLS, AND TELOMERASE INHIBITION REQUIRES PROLIFERATING CELLS OVER A SUFFICIENT NUMBER OF POPULATION DOUBLINGS TO INDUCE TUMOR SUPPRESSIVE SENESCENCE. THESE LIMITATIONS MAY EXPLAIN THE MODERATE SUCCESS RATES IN MANY CLINICAL STUDIES. DESPITE EXTENSIVE STUDIES, ONLY ONE VACCINE AND ONE TELOMERASE ANTAGONIST ARE ROUTINELY USED IN CLINICAL WORK. FOR COMPLETE ERADICATION OF ALL SUBPOPULATIONS OF CANCER CELLS A SIMULTANEOUS TARGETING OF SEVERAL MECHANISMS WILL LIKELY BE NEEDED. POSSIBLE TECHNICAL IMPROVEMENTS HAVE BEEN PROPOSED INCLUDING THE DEVELOPMENT OF MORE SPECIFIC INHIBITORS, METHODS TO INCREASE THE EFFICACY OF VACCINATION METHODS, AND PERSONALIZED APPROACHES. TELOMERASE ACTIVATION AND CELL REJUVENATION IS SUCCESSFULLY USED IN REGENERATIVE MEDICINE FOR TISSUE ENGINEERING AND RECONSTRUCTIVE SURGERY. HOWEVER, THERE ARE ALSO A NUMBER OF PITFALLS IN THE TREATMENT WITH TELOMERASE ACTIVATING PROCEDURES FOR THE WHOLE ORGANISM AND FOR LONGER PERIODS OF TIME. EXTENDED CELL LIFESPAN MAY ACCUMULATE RARE GENETIC AND EPIGENETIC ABERRATIONS THAT CAN CONTRIBUTE TO MALIGNANT TRANSFORMATION. THEREFORE, NOVEL VECTOR SYSTEMS HAVE BEEN DEVELOPED FOR A 'MILD' INTEGRATION OF TELOMERASE INTO THE HOST GENOME AND LOSS OF THE VECTOR IN RAPIDLY-PROLIFERATING CELLS. IT IS CURRENTLY UNCLEAR IF THIS TECHNIQUE CAN ALSO BE USED IN HUMAN BEINGS TO TREAT CHRONIC DISEASES, SUCH AS ATHEROSCLEROSIS. 2016 18 6296 36 THE PROSPECTS FOR A SIMPLIFIED AND INTERNATIONALLY HARMONIZED APPROACH TO THE DETECTION OF POSSIBLE HUMAN CARCINOGENS AND MUTAGENS. IT IS PROPOSED THAT THE MANY SETS OF REGULATORY GUIDELINES FOR THE ASSESSMENT OF CHEMICAL CARCINOGENICITY AND MUTAGENICITY SHOULD BE SIMPLIFIED AND HARMONIZED IN LIGHT OF CURRENT EXPERIMENTAL DATA. DATA ARE DISCUSSED WHICH ILLUSTRATE THAT AN ABSOLUTE DISTINCTION WOULD BE DRAWN BETWEEN ASSAYS CONDUCTED IN VITRO FROM THOSE IN VIVO, AND THAT THE GENOTOXICITY OF A CHEMICAL CAN BE ADEQUATELY DEFINED USING A COMBINATION OF THE SALMONELLA MUTATION ASSAY AND ONE FOR THE ASSESSMENT OF CHROMOSOME ABERRATIONS IN VITRO. IT IS SPECIFICALLY RECOMMENDED THAT ONCE A CHEMICAL HAS SHOWN A CLEAR POSITIVE RESPONSE IN VITRO, FURTHER SHORT-TERM ASSAYS SHOULD BE CONDUCTED IN VIVO; THIS AVOIDS CONSIDERING THE 'WEIGHT OF EVIDENCE' OF IN VITRO DATA, THE DANGERS OF WHICH ARE ILLUSTRATED. IT HAS NOW BEEN UNEQUIVOCALLY ESTABLISHED THAT NOT ALL IN VITRO GENOTOXINS PROVE CARCINOGENIC TO MAMMALS. IT IS THEREFORE RECOMMENDED THAT ALL NEW IN VITRO GENOTOXINS SHOULD BE ASSESSED IN VIVO USING THE MOUSE BONE MARROW MICRONUCLEUS ASSAY, AND IF A NEGATIVE RESPONSE IS OBSERVED, A LIVER GENOTOXICITY TEST. AT PRESENT AN ASSAY FOR THE INDUCTION OF UNSCHEDULED DNA SYNTHESIS (UDS) IN THE LIVER IS THE MOST WELL DEVELOPED FOR THIS PURPOSE. CURRENT DATA INDICATE THAT AN IN VITRO GENOTOXIN FOUND TO BE INACTIVE IN THESE TWO IN VIVO ASSAYS WILL BE NEITHER CARCINOGENIC NOR MUTAGENIC TO THE GERM CELLS OF MAMMALS. EQUALLY, GENOTOXICITY PRODUCED IN MAMMALS INDICATES A CARCINOGENIC AND MUTAGENIC POTENTIAL WHICH CAN USUALLY ONLY BE COUNTERED BY APPROPRIATE CHRONIC BIOASSAYS. THE USE OF SHORT-TERM IN VIVO ASSAYS IN THIS CRITICAL ROLE REQUIRES ATTENTION TO THE SELECTION OF APPROPRIATE DOSE-LEVELS AND ROUTES OF EXPOSURE - THESE ISSUES ARE DISCUSSED. THE ABOVE TESTING STRATEGY WILL NOT DETECT CERTAIN ANIMAL CARCINOGENS, SOME OF WHICH ARE SPECIFICALLY DISCUSSED. THESE CARCINOGENS HAVE BEEN VARIOUSLY REFERRED TO IN THE LITERATURE AS EPIGENETIC/NON-GENOTOXIC/HORMONAL/TOXIC/AMBIGUOUS OR AMBIVALENT CARCINOGENS. IT IS SUGGESTED THAT THEY PRESENT A MINOR POTENTIAL HAZARD TO MAN WHEN COMPARED WITH THAT OF GENOTOXIC CARCINOGENS AND THAT THEIR SHORT-TERM DETECTION CAN ONLY BE ACHIEVED BY THE DEVELOPMENT OF NEW WHOLE MAMMAL ASSAYS EMPLOYING NON-GENETIC ENDPOINTS. THIS IS IN CONTRAST TO THE PRESENT TENDENCY TO EMPLOY ADDITIONAL GENOTOXICITY ASSAYS FOR THEIR DETECTION IN THE UNJUSTIFIED BELIEF THAT THEY POSSESS AN EXQUISITE SPECIFICITY OF GENOTOXIC ACTION. THIS ARTICLE REPRESENTS A PERSONAL VIEW, BUT THE TESTING STRATEGY PROPOSED IS BASED TO A LARGE EXTENT ON THE ORIGINAL THREE-TIER APPROACH OF BRIDGES.(ABSTRACT TRUNCATED AT 400 WORDS) 1986 19 2535 26 EPIGENETICS IN CHRONIC LYMPHOCYTIC LEUKEMIA. ENORMOUS EVIDENCE HAS ACCUMULATED IN THE PAST DECADES THAT ESTABLISHES THE IMPORTANCE OF EPIGENETIC MODIFICATIONS IN CANCER AND HAS RESULTED IN SHIFTING THE FOCUS FROM ENTIRELY GENETIC-BASED STUDIES TO INTEGRATED STUDIES INVOLVING BOTH GENETIC AND EPIGENETIC ALTERATIONS. CHRONIC LYMPHOCYTIC LEUKEMIA (CLL) IS ONE SUCH EXAMPLE WHERE STUDIES INVOLVING EPIGENETIC ABERRATIONS HAVE ACCELERATED THE SEARCH FOR AFFECTED GENES, WHICH WAS INITIALLY RESTRICTED TO COMMONLY DELETED CHROMOSOMAL REGIONS. MANY NOVEL GENES THAT ARE EPIGENETICALLY SILENCED IN CLL HAVE BEEN IDENTIFIED. ADVANCES IN THE UNDERSTANDING OF POST-TRANSLATIONAL HISTONE MODIFICATIONS AND DNA METHYLATION IN NORMAL AND IN CLL CELLS HAVE PROVEN TO BE EXTREMELY BENEFICIAL IN FINDING POWERFUL DIAGNOSTIC MARKERS, AS WELL AS IN EXPLORING NOVEL THERAPIES. AT PRESENT, THE FIELD OF EPIGENETICS IS AT AN EVOLVING STAGE, BUT THERE IS NO DOUBT THAT FURTHER UNRAVELING OF ITS CAUSE AND EFFECTS IN TRANSFORMED CELLS WILL BRING A NEW REVOLUTION IN CANCER THERAPEUTICS. 2006 20 1844 37 EFFECTS OF THE LIFESTYLE HABITS IN BREAST CANCER TRANSCRIPTIONAL REGULATION. THROUGH RESEARCH CARRIED OUT IN THE LAST 25 YEARS ABOUT THE BREAST CANCER ETIOLOGY, IT HAS BEEN POSSIBLE TO ESTIMATE THAT LESS THAN 10 % OF PATIENTS WHO ARE DIAGNOSED WITH THE CONDITION ARE CARRIERS OF SOME GERMLINE OR SOMATIC MUTATION. THE CLINICAL REPORTS OF BREAST CANCER PATIENTS WITH HEALTHY TWINS AND THE DEVELOPMENT OF DISEASE IN WOMEN WITHOUT HIGH PENETRANCE MUTATIONS DETECTED, WARN THE PARTICIPATION MORE FACTORS IN THE TRANSFORMATION PROCESS. THE HIGH INCIDENCE OF MAMMARY ADENOCARCINOMA IN THE MODERN WOMAN AND THE URGENT NEED FOR NEW METHODS OF PREVENTION AND EARLY DETECTION HAVE DEMANDED MORE INFORMATION ABOUT THE ROLE THAT ENVIRONMENT AND LIFESTYLE HAVE ON THE TRANSFORMATION OF MAMMARY GLAND EPITHELIAL CELLS. OBESITY, ALCOHOLISM AND SMOKING ARE FACTORS THAT HAVE SHOWN A CLOSE CORRELATION WITH THE RISK OF DEVELOPING BREAST CANCER. AND ALTHOUGH THESE CONDITIONS AFFECT DIFFERENT CELL REGULATION LEVELS, THE STUDY OF ITS EFFECTS IN THE MECHANISMS OF TRANSCRIPTIONAL AND EPIGENETIC REGULATION IS CONSIDERED CRITICAL FOR A BETTER UNDERSTANDING OF THE LOSS OF IDENTITY OF EPITHELIAL CELLS DURING CARCINOGENESIS OF THIS TISSUE. THE MAIN OBJECTIVE OF THIS REVIEW WAS TO ESTABLISH THE IMPORTANCE OF CHANGES OCCURRING TO TRANSCRIPTIONAL LEVEL IN THE MAMMARY GLAND AS A CONSEQUENCE OF ACUTE OR CHRONIC EXPOSURE TO HARMFUL PRODUCTS SUCH AS OBESITY-CAUSING FOODS, ETHANOL AND CIGARETTE SMOKE COMPONENTS. AT ANALYZE THE MAIN STUDIES RELATED TO TOPIC, IT HAS CONCLUDED THAT THE UNDERSTANDING OF EFFECTS CAUSED BY THE LIFESTYLE FACTORS IN PERFORMANCE OF THE TRANSCRIPTIONAL MECHANISMS THAT DETERMINE GENE EXPRESSION OF THE MAMMARY GLAND EPITHELIAL CELLS, MAY HELP EXPLAIN THE DEVELOPMENT OF THIS DISEASE IN WOMEN WITHOUT GENETIC PROPENSITY AND DIFFERENT PHENOTYPIC MANIFESTATIONS OF THIS CANCER TYPE. 2016