1 3688 160 INFLAMMATION: GEARING THE JOURNEY TO CANCER. CHRONIC INFLAMMATION PLAYS A MULTIFACETED ROLE IN CARCINOGENESIS. MOUNTING EVIDENCE FROM PRECLINICAL AND CLINICAL STUDIES SUGGESTS THAT PERSISTENT INFLAMMATION FUNCTIONS AS A DRIVING FORCE IN THE JOURNEY TO CANCER. THE POSSIBLE MECHANISMS BY WHICH INFLAMMATION CAN CONTRIBUTE TO CARCINOGENESIS INCLUDE INDUCTION OF GENOMIC INSTABILITY, ALTERATIONS IN EPIGENETIC EVENTS AND SUBSEQUENT INAPPROPRIATE GENE EXPRESSION, ENHANCED PROLIFERATION OF INITIATED CELLS, RESISTANCE TO APOPTOSIS, AGGRESSIVE TUMOR NEOVASCULARIZATION, INVASION THROUGH TUMOR-ASSOCIATED BASEMENT MEMBRANE AND METASTASIS, ETC. INFLAMMATION-INDUCED REACTIVE OXYGEN AND NITROGEN SPECIES CAUSE DAMAGE TO IMPORTANT CELLULAR COMPONENTS (E.G., DNA, PROTEINS AND LIPIDS), WHICH CAN DIRECTLY OR INDIRECTLY CONTRIBUTE TO MALIGNANT CELL TRANSFORMATION. OVEREXPRESSION, ELEVATED SECRETION, OR ABNORMAL ACTIVATION OF PROINFLAMMATORY MEDIATORS, SUCH AS CYTOKINES, CHEMOKINES, CYCLOOXYGENASE-2, PROSTAGLANDINS, INDUCIBLE NITRIC OXIDE SYNTHASE, AND NITRIC OXIDE, AND A DISTINCT NETWORK OF INTRACELLULAR SIGNALING MOLECULES INCLUDING UPSTREAM KINASES AND TRANSCRIPTION FACTORS FACILITATE TUMOR PROMOTION AND PROGRESSION. WHILE INFLAMMATION PROMOTES DEVELOPMENT OF CANCER, COMPONENTS OF THE TUMOR MICROENVIRONMENT, SUCH AS TUMOR CELLS, STROMAL CELLS IN SURROUNDING TISSUE AND INFILTRATED INFLAMMATORY/IMMUNE CELLS GENERATE AN INTRATUMORAL INFLAMMATORY STATE BY ABERRANT EXPRESSION OR ACTIVATION OF SOME PROINFLAMMATORY MOLECULES. MANY OF PROINFLAMMATORY MEDIATORS, ESPECIALLY CYTOKINES, CHEMOKINES AND PROSTAGLANDINS, TURN ON THE ANGIOGENIC SWITCHES MAINLY CONTROLLED BY VASCULAR ENDOTHELIAL GROWTH FACTOR, THEREBY INDUCING INFLAMMATORY ANGIOGENESIS AND TUMOR CELL-STROMA COMMUNICATION. THIS WILL END UP WITH TUMOR ANGIOGENESIS, METASTASIS AND INVASION. MOREOVER, CELLULAR MICRORNAS ARE EMERGING AS A POTENTIAL LINK BETWEEN INFLAMMATION AND CANCER. THE PRESENT ARTICLE HIGHLIGHTS THE ROLE OF VARIOUS PROINFLAMMATORY MEDIATORS IN CARCINOGENESIS AND THEIR PROMISE AS POTENTIAL TARGETS FOR CHEMOPREVENTION OF INFLAMMATION-ASSOCIATED CARCINOGENESIS. 2008 2 1864 57 EMERGING AVENUES LINKING INFLAMMATION AND CANCER. THE ROLE OF INFLAMMATION IN CARCINOGENESIS HAS BEEN EXTENSIVELY INVESTIGATED AND WELL DOCUMENTED. MANY BIOCHEMICAL PROCESSES THAT ARE ALTERED DURING CHRONIC INFLAMMATION HAVE BEEN IMPLICATED IN TUMORIGENESIS. THESE INCLUDE SHIFTING CELLULAR REDOX BALANCE TOWARD OXIDATIVE STRESS; INDUCTION OF GENOMIC INSTABILITY; INCREASED DNA DAMAGE; STIMULATION OF CELL PROLIFERATION, METASTASIS, AND ANGIOGENESIS; DEREGULATION OF CELLULAR EPIGENETIC CONTROL OF GENE EXPRESSION; AND INAPPROPRIATE EPITHELIAL-TO-MESENCHYMAL TRANSITION. A WIDE ARRAY OF PROINFLAMMATORY CYTOKINES, PROSTAGLANDINS, NITRIC OXIDE, AND MATRICELLULAR PROTEINS ARE CLOSELY INVOLVED IN PREMALIGNANT AND MALIGNANT CONVERSION OF CELLS IN A BACKGROUND OF CHRONIC INFLAMMATION. INAPPROPRIATE TRANSCRIPTION OF GENES ENCODING INFLAMMATORY MEDIATORS, SURVIVAL FACTORS, AND ANGIOGENIC AND METASTATIC PROTEINS IS THE KEY MOLECULAR EVENT IN LINKING INFLAMMATION AND CANCER. ABERRANT CELL SIGNALING PATHWAYS COMPRISING VARIOUS KINASES AND THEIR DOWNSTREAM TRANSCRIPTION FACTORS HAVE BEEN IDENTIFIED AS THE MAJOR CONTRIBUTORS IN ABNORMAL GENE EXPRESSION ASSOCIATED WITH INFLAMMATION-DRIVEN CARCINOGENESIS. THE POSTTRANSCRIPTIONAL REGULATION OF GENE EXPRESSION BY MICRORNAS ALSO PROVIDES THE MOLECULAR BASIS FOR LINKING INFLAMMATION TO CANCER. THIS REVIEW HIGHLIGHTS THE MULTIFACETED ROLE OF INFLAMMATION IN CARCINOGENESIS IN THE CONTEXT OF ALTERED CELLULAR REDOX SIGNALING. 2012 3 6395 52 THE ROLE OF THE MEDIATORS OF INFLAMMATION IN CANCER DEVELOPMENT. EPIGENETIC DISORDERS SUCH AS POINT MUTATIONS IN CELLULAR TUMOR SUPPRESSOR GENES, DNA METHYLATION AND POST-TRANSLATIONAL MODIFICATIONS ARE NEEDED TO TRANSFORMATION OF NORMAL CELLS INTO CANCER CELLS. THESE EVENTS RESULT IN ALTERATIONS IN CRITICAL PATHWAYS RESPONSIBLE FOR MAINTAINING THE NORMAL CELLULAR HOMEOSTASIS, TRIGGERING TO AN INFLAMMATORY RESPONSE WHICH CAN LEAD THE DEVELOPMENT OF CANCER. THE INFLAMMATORY RESPONSE IS A UNIVERSAL DEFENSE MECHANISM ACTIVATED IN RESPONSE TO AN INJURY TISSUE, OF ANY NATURE, THAT INVOLVES BOTH INNATE AND ADAPTIVE IMMUNE RESPONSES, THROUGH THE COLLECTIVE ACTION OF A VARIETY OF SOLUBLE MEDIATORS. MANY INFLAMMATORY SIGNALING PATHWAYS ARE ACTIVATED IN SEVERAL TYPES OF CANCER, LINKING CHRONIC INFLAMMATION TO TUMORIGENESIS PROCESS. THUS, INFLAMMATORY RESPONSES PLAY DECISIVE ROLES AT DIFFERENT STAGES OF TUMOR DEVELOPMENT, INCLUDING INITIATION, PROMOTION, GROWTH, INVASION, AND METASTASIS, AFFECTING ALSO THE IMMUNE SURVEILLANCE. IMMUNE CELLS THAT INFILTRATE TUMORS ENGAGE IN AN EXTENSIVE AND DYNAMIC CROSSTALK WITH CANCER CELLS, AND SOME OF THE MOLECULAR EVENTS THAT MEDIATE THIS DIALOG HAVE BEEN REVEALED. A RANGE OF INFLAMMATION MEDIATORS, INCLUDING CYTOKINES, CHEMOKINES, FREE RADICALS, PROSTAGLANDINS, GROWTH AND TRANSCRIPTION FACTORS, MICRORNAS, AND ENZYMES AS, CYCLOOXYGENASE AND MATRIX METALLOPROTEINASE, COLLECTIVELY ACTS TO CREATE A FAVORABLE MICROENVIRONMENT FOR THE DEVELOPMENT OF TUMORS. IN THIS REVIEW ARE PRESENTED THE MAIN MEDIATORS OF THE INFLAMMATORY RESPONSE AND DISCUSSED THE LIKELY MECHANISMS THROUGH WHICH, THEY INTERACT WITH EACH OTHER TO CREATE A CONDITION FAVORABLE TO DEVELOPMENT OF CANCER. 2015 4 1232 54 CROSSTALK BETWEEN INFLAMMATORY SIGNALING AND METHYLATION IN CANCER. INFLAMMATION IS AN INTRICATE IMMUNE RESPONSE AGAINST INFECTION AND TISSUE DAMAGE. WHILE THE INITIAL IMMUNE RESPONSE IS IMPORTANT FOR PREVENTING TUMORIGENESIS, CHRONIC INFLAMMATION IS IMPLICATED IN CANCER PATHOGENESIS. IT HAS BEEN LINKED TO VARIOUS STAGES OF TUMOR DEVELOPMENT INCLUDING TRANSFORMATION, PROLIFERATION, ANGIOGENESIS, AND METASTASIS. IMMUNE CELLS, THROUGH THE PRODUCTION OF INFLAMMATORY MEDIATORS SUCH AS CYTOKINES, CHEMOKINES, TRANSFORMING GROWTH FACTORS, AND ADHESION MOLECULES CONTRIBUTE TO THE SURVIVAL, GROWTH, AND PROGRESSION OF THE TUMOR IN ITS MICROENVIRONMENT. THE ABERRANT EXPRESSION AND SECRETION OF PRO-INFLAMMATORY AND GROWTH FACTORS BY THE TUMOR CELLS RESULT IN THE RECRUITMENT OF IMMUNE CELLS, THUS CREATING A MUTUAL CROSSTALK. THE RECIPROCAL SIGNALING BETWEEN THE TUMOR CELLS AND THE IMMUNE CELLS CREATES AND MAINTAINS A SUCCESSFUL TUMOR NICHE. MANY INFLAMMATORY FACTORS ARE REGULATED BY EPIGENETIC MECHANISMS INCLUDING DNA METHYLATION AND HISTONE MODIFICATIONS. IN PARTICULAR, DNA AND HISTONE METHYLATION ARE CRUCIAL FORMS OF TRANSCRIPTIONAL REGULATION AND ABERRANT METHYLATION HAS BEEN ASSOCIATED WITH DEREGULATED GENE EXPRESSION IN ONCOGENESIS. SUCH DEREGULATIONS HAVE BEEN REPORTED IN BOTH SOLID TUMORS AND HEMATOLOGICAL MALIGNANCIES. WITH TECHNOLOGICAL ADVANCEMENTS TO STUDY GENOME-WIDE EPIGENETIC LANDSCAPES, IT IS NOW POSSIBLE TO IDENTIFY MOLECULAR MECHANISMS UNDERLYING ALTERED INFLAMMATORY PROFILES IN CANCER. IN THIS REVIEW, WE DISCUSS THE ROLE OF DNA AND HISTONE METHYLATION IN REGULATION OF INFLAMMATORY PATHWAYS IN HUMAN CANCERS AND REVIEW THE MERITS AND CHALLENGES OF TARGETING INFLAMMATORY MEDIATORS AS WELL AS EPIGENETIC REGULATORS IN CANCER. 2021 5 6309 34 THE REGULATION OF MIRNAS IN INFLAMMATION-RELATED CARCINOGENESIS. CHRONIC INFLAMMATION PLAYS IMPORTANT ROLES IN THE INITIATION AND DEVELOPMENT OF VARIOUS CANCERS, PARTICULARLY GASTROINTESTINAL CANCER. CANCER IS CHARACTERIZED BY STEPWISE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS OF GENES. AS A HIGH RISK FACTOR FOR CANCER, CHRONIC INFLAMMATORY RESPONSE PRODUCES GREAT AMOUNT OF MEDIATORS, INCLUDING CYTOKINES, REACTIVE OXYGEN AND NITROGEN SPECIES, PROTEINASES, WHICH CAN INDUCE GENETIC AND EPIGENETIC CHANGES OF CANCER-ASSOCIATED GENES AND PATHWAYS. FURTHERMORE, INFLAMMATION ALSO MODULATES THE EXPRESSION OF MIRNAS THAT NOT ONLY REGULATE THE EXPRESSION OF TUMOR-RELATED PROTEINS BUT ALSO ENHANCE THE TUMOR-PROMOTING INFLAMMATORY PROCESS. IN THE CURRENT REVIEW, WE SUMMARIZE THE MECHANISMS BY WHICH INFLAMMATORY MEDIATORS AND SIGNALING REGULATE THE BIOSYNTHESIS OF MIRNAS, AS WELL AS THE INVOLVEMENT OF MIRNAS IN THE FEEDBACK LOOPS PROMOTING INFLAMMATION-ASSOCIATED CARCINOGENESIS. 2015 6 3921 46 LINKING INFLAMMATION TO CELL CYCLE PROGRESSION. RISK OF GASTROINTESTINAL CANCERS IS CLOSELY RELATED TO INCREASED LEVELS OF OXIDANTS IN THE BALANCE BETWEEN OXIDANT AND ANTI-OXIDANT AGENTS. A POSSIBLE EXPLANATION OF THIS EPIDEMIOLOGICAL OBSERVATION IS THE LOCAL LOSS OF THE EPITHELIAL BARRIER FUNCTION WITH A FOCAL INFLAMMATORY RESPONSE. ACCORDINGLY, CHRONIC INFLAMMATORY DISEASES REPRESENT WELL-KNOWN RISK FACTORS FOR CANCER AND, ON THE OTHER HAND, IT IS KNOWN THAT ANTI-INFLAMMATORY AGENTS, DEMULCENTS AND ANTIOXIDANTS MARKEDLY INHIBIT THE DEVELOPMENT OF COLON CANCER IN ANIMAL MODELS AS WELL IN HUMANS. AT MOLECULAR LEVEL A KEY ROLE IN THE PROCESS THAT LINK INFLAMMATION TO CELLULAR TRANSFORMATION SEEMS TO BE PLAYED BY ACTIVATION OF CYCLOOXYGENASE-2 (COX-2) TOGETHER WITH PRODUCTION OF REACTIVE OXYGEN INTERMEDIATE (ROI). BOTH THESE EVENTS HAVE BEEN STRICTLY LINKED WITH CELL PROLIFERATION AND TRANSFORMATION, ALTHOUGH THE INTRACELLULAR PATHWAYS INVOLVED IN THESE PROCESSES ARE STILL NOT COMPLETELY UNDERSTOOD. THE UNCONTROLLED PROLIFERATION, WHICH IS A LANDMARK OF CELLULAR TRANSFORMATION, IS ACCOMPANIED BY THE DEREGULATION OF PROTEINS INVOLVED IN THE CONTROL OF CELL CYCLE CHECKPOINTS. ALTERED EXPRESSION AND FUNCTION OF CYCLOOXYGENASE AND NITRIC OXIDE SYNTHASE SEEM TO INFLUENCE, AMONG OTHERS, THE EXPRESSION OF PROTEINS INVOLVED IN THE REGULATION OF CELL CYCLE PROGRESSION. SIMILARLY, ANTI-INFLAMMATORY AND ANTIOXIDANT AGENTS MAY ALSO ACT ON THE EXPRESSION AND FUNCTION OF SEVERAL CELL CYCLE REGULATING PROTEINS. UNDERSTANDING THE MECHANISMS BY WHICH CHRONIC INFLAMMATION CONTRIBUTES TO GENETIC AND EPIGENETIC CHANGES INVOLVED IN THE REGULATION OF CRITICAL CELL CYCLE CHECKPOINTS MAY HELP TO DEVELOP MORE AND MORE SPECIFIC TREATMENT STRATEGIES FOR REDUCING MALIGNANT TRANSFORMATION OF THESE INFLAMMATORY DISEASES. 2004 7 1150 51 CONNECTION BETWEEN INFLAMMATION AND CARCINOGENESIS IN GASTROINTESTINAL TRACT: FOCUS ON TGF-BETA SIGNALING. INFLAMMATION IS A PRIMARY DEFENSE PROCESS AGAINST VARIOUS EXTRACELLULAR STIMULI, SUCH AS VIRUSES, PATHOGENS, FOODS, AND ENVIRONMENTAL POLLUTANTS. WHEN CELLS RESPOND TO STIMULI FOR SHORT PERIODS OF TIME, IT RESULTS IN ACUTE OR PHYSIOLOGICAL INFLAMMATION. HOWEVER, IF THE STIMULATION IS SUSTAINED FOR LONGER TIME OR A PATHOLOGICAL STATE OCCURS, IT IS KNOWN AS CHRONIC OR PATHOLOGICAL INFLAMMATION. SEVERAL STUDIES HAVE SHOWN THAT TUMORIGENESIS IN THE GASTROINTESTINAL (GI) TRACT IS CLOSELY ASSOCIATED WITH CHRONIC INFLAMMATION, FOR WHICH ABNORMAL CELLULAR ALTERATIONS THAT ACCOMPANY CHRONIC INFLAMMATION SUCH AS OXIDATIVE STRESSES, GENE MUTATIONS, EPIGENETIC CHANGES, AND INFLAMMATORY CYTOKINES, ARE SHARED WITH CARCINOGENIC PROCESSES, WHICH FORMS A CRITICAL CROSS-LINK BETWEEN CHRONIC INFLAMMATION AND CARCINOGENESIS. TRANSFORMING GROWTH FACTOR (TGF)-BETA IS A MULTI-POTENT CYTOKINE THAT PLAYS AN IMPORTANT ROLE IN REGULATION OF CELL GROWTH, APOPTOSIS AND DIFFERENTIATION. MOST IMPORTANTLY, TGF-BETA IS A STRONG ANTI-INFLAMMATORY CYTOKINE THAT REGULATES THE DEVELOPMENT OF EFFECTOR CELLS. TGF-BETA HAS A SUPPRESSIVE EFFECT ON CARCINOGENESIS UNDER NORMAL CONDITIONS BY INHIBITING ABNORMAL CELL GROWTH, BUT ON THE OTHER HAND, MANY GI CANCERS ORIGINATE FROM UNCONTROLLED CELL GROWTH AND DIFFERENTIATION BY GENETIC LOSS OF TGF-BETA SIGNALING MOLECULES OR PERTURBATION OF TGF-BETA ADAPTORS. ONCE A TUMOR HAS DEVELOPED, TGF-BETA EXERTS A PROMOTING EFFECT ON THE TUMOR ITSELF AND STROMAL CELLS TO ENHANCE CELL GROWTH, ALTER THE RESPONSIVENESS OF TUMOR CELLS TO STIMULATE INVASION AND METASTASIS, AND INHIBITED IMMUNE SURVEILLANCE. THEREFORE, NOVEL DEVELOPMENT OF THERAPEUTIC AGENTS TO INHIBIT TGF-BETA-INDUCED PROGRESSION OF TUMOR AND TO RETAIN ITS GROWTH INHIBITORY ACTIVITIES, IN ADDITION TO ANTI-INFLAMMATORY ACTIONS, COULD BE USEFUL IN ONCOLOGY. IN THIS REVIEW, WE DISCUSS THE ROLE OF TGF-BETA IN INFLAMMATION AND CARCINOGENESIS OF THE GI TRACT RELATED TO ABNORMAL TGF-BETA SIGNALING. 2010 8 3672 31 INFLAMMATION AND CANCER: AN ANCIENT LINK WITH NOVEL POTENTIALS. INFECTION AND CHRONIC INFLAMMATION CONTRIBUTE TO ABOUT 1 IN 4 OF ALL CANCER CASES. MEDIATORS OF THE INFLAMMATORY RESPONSE, E.G., CYTOKINES, FREE RADICALS, PROSTAGLANDINS AND GROWTH FACTORS, CAN INDUCE GENETIC AND EPIGENETIC CHANGES INCLUDING POINT MUTATIONS IN TUMOR SUPPRESSOR GENES, DNA METHYLATION AND POST-TRANSLATIONAL MODIFICATIONS, CAUSING ALTERATIONS IN CRITICAL PATHWAYS RESPONSIBLE FOR MAINTAINING THE NORMAL CELLULAR HOMEOSTASIS AND LEADING TO THE DEVELOPMENT AND PROGRESSION OF CANCER. RECENT DISCOVERY OF AN INTERACTION BETWEEN MICRORNAS AND INNATE IMMUNITY DURING INFLAMMATION HAS FURTHER STRENGTHENED THE ASSOCIATION BETWEEN INFLAMMATION AND CANCER. 2007 9 5412 39 REGULATION OF ANTITUMOR IMMUNITY BY INFLAMMATION-INDUCED EPIGENETIC ALTERATIONS. CHRONIC INFLAMMATION PROMOTES TUMOR DEVELOPMENT, PROGRESSION, AND METASTATIC DISSEMINATION AND CAUSES TREATMENT RESISTANCE. THE ACCUMULATION OF GENETIC ALTERATIONS AND LOSS OF NORMAL CELLULAR REGULATORY PROCESSES ARE NOT ONLY ASSOCIATED WITH CANCER GROWTH AND PROGRESSION BUT ALSO RESULT IN THE EXPRESSION OF TUMOR-SPECIFIC AND TUMOR-ASSOCIATED ANTIGENS THAT MAY ACTIVATE ANTITUMOR IMMUNITY. THIS ANTAGONISM BETWEEN INFLAMMATION AND IMMUNITY AND THE ABILITY OF CANCER CELLS TO AVOID IMMUNE DETECTION AFFECT THE COURSE OF CANCER DEVELOPMENT AND TREATMENT OUTCOMES. WHILE INFLAMMATION, PARTICULARLY ACUTE INFLAMMATION, SUPPORTS T-CELL PRIMING, ACTIVATION, AND INFILTRATION INTO INFECTED TISSUES, CHRONIC INFLAMMATION IS MOSTLY IMMUNOSUPPRESSIVE. HOWEVER, THE MAIN MECHANISMS THAT DICTATE THE OUTCOME OF THE INFLAMMATION-IMMUNITY INTERPLAY ARE NOT WELL UNDERSTOOD. RECENT DATA SUGGEST THAT INFLAMMATION TRIGGERS EPIGENETIC ALTERATIONS IN CANCER CELLS AND COMPONENTS OF THE TUMOR MICROENVIRONMENT. THESE ALTERATIONS CAN AFFECT AND MODULATE NUMEROUS ASPECTS OF CANCER DEVELOPMENT, INCLUDING TUMOR GROWTH, THE METABOLIC STATE, METASTATIC SPREAD, IMMUNE ESCAPE, AND IMMUNOSUPPRESSIVE OR IMMUNOSUPPORTIVE LEUKOCYTE GENERATION. IN THIS REVIEW, WE DISCUSS THE ROLE OF INFLAMMATION IN INITIATING EPIGENETIC ALTERATIONS IN IMMUNE CELLS, CANCER-ASSOCIATED FIBROBLASTS, AND CANCER CELLS AND SUGGEST HOW AND WHEN EPIGENETIC INTERVENTIONS CAN BE COMBINED WITH IMMUNOTHERAPIES TO IMPROVE THERAPEUTIC OUTCOMES. 2022 10 2335 37 EPIGENETIC REGULATION OF INFLAMMATORY CYTOKINES AND ASSOCIATED GENES IN HUMAN MALIGNANCIES. INFLAMMATION IS A MULTIFACETED DEFENSE RESPONSE OF IMMUNE SYSTEM AGAINST INFECTION. CHRONIC INFLAMMATION HAS BEEN IMPLICATED AS AN IMMINENT THREAT FOR MAJOR HUMAN MALIGNANCIES AND IS DIRECTLY LINKED TO VARIOUS STEPS INVOLVED IN TUMORIGENESIS. INFLAMMATORY CYTOKINES, INTERLEUKINS, INTERFERONS, TRANSFORMING GROWTH FACTORS, CHEMOKINES, AND ADHESION MOLECULES HAVE BEEN ASSOCIATED WITH CHRONIC INFLAMMATION. NUMEROUS CYTOKINES ARE REPORTED TO BE ABERRANTLY REGULATED BY DIFFERENT EPIGENETIC MECHANISMS LIKE DNA METHYLATION AND HISTONE MODIFICATIONS IN TUMOR TISSUES, CONTRIBUTING TO PATHOGENESIS OF TUMOR IN MULTIPLE WAYS. SOME OF THESE CYTOKINES ALSO WORK AS EPIGENETIC REGULATORS OF OTHER CRUCIAL GENES IN TUMOR BIOLOGY, EITHER DIRECTLY OR INDIRECTLY. SUCH REGULATIONS ARE REPORTED IN LUNG, BREAST, CERVICAL, GASTRIC, COLORECTAL, PANCREATIC, PROSTATE, AND HEAD AND NECK CANCERS. EPIGENETICS OF INFLAMMATORY MEDIATORS IN CANCER IS CURRENTLY SUBJECT OF EXTENSIVE RESEARCH. THESE INVESTIGATIONS MAY HELP IN UNDERSTANDING CANCER BIOLOGY AND TO DEVELOP EFFECTIVE THERAPEUTIC STRATEGIES. THE PURPOSE OF THIS PAPER IS TO HAVE A BRIEF VIEW OF THE ABERRANT REGULATION OF INFLAMMATORY CYTOKINES IN HUMAN MALIGNANCIES. 2015 11 5554 45 ROLE OF EPIGENETICS IN TRANSFORMATION OF INFLAMMATION INTO COLORECTAL CANCER. MOLECULAR MECHANISMS ASSOCIATED WITH INFLAMMATION-PROMOTED TUMORIGENESIS HAVE BECOME AN IMPORTANT TOPIC IN CANCER RESEARCH. VARIOUS ABNORMAL EPIGENETIC CHANGES, INCLUDING DNA METHYLATION, HISTONE MODIFICATION, CHROMATIN REMODELING, AND NONCODING RNA REGULATION, OCCUR DURING THE TRANSFORMATION OF CHRONIC INFLAMMATION INTO COLORECTAL CANCER (CRC). THESE CHANGES NOT ONLY ACCELERATE TRANSFORMATION BUT ALSO LEAD TO CANCER PROGRESSION AND METASTASIS BY ACTIVATING CARCINOGENIC SIGNALING PATHWAYS. THE NF-KAPPAB AND STAT3 SIGNALING PATHWAYS PLAY A PARTICULARLY IMPORTANT ROLE IN THE TRANSFORMATION OF INFLAMMATION INTO CRC, AND BOTH ARE CRITICAL TO CELLULAR SIGNAL TRANSDUCTION AND CONSTANTLY ACTIVATED IN CANCER BY VARIOUS ABNORMAL CHANGES INCLUDING EPIGENETICS. THE NF-KAPPAB AND STAT3 SIGNALS CONTRIBUTE TO THE MICROENVIRONMENT FOR TUMORIGENESIS THROUGH SECRETION OF A LARGE NUMBER OF PRO-INFLAMMATORY CYTOKINES AND THEIR CROSSTALK IN THE NUCLEUS MAKES IT EVEN MORE DIFFICULT TO TREAT CRC. COMPARED WITH GENE MUTATION THAT IS IRREVERSIBLE, EPIGENETIC INHERITANCE IS REVERSIBLE OR CAN BE ALTERED BY THE INTERVENTION. THEREFORE, UNDERSTANDING THE ROLE OF EPIGENETIC INHERITANCE IN THE INFLAMMATION-CANCER TRANSFORMATION MAY ELUCIDATE THE PATHOGENESIS OF CRC AND PROMOTE THE DEVELOPMENT OF INNOVATIVE DRUGS TARGETING TRANSFORMATION TO PREVENT AND TREAT THIS MALIGNANCY. THIS REVIEW SUMMARIZES THE LITERATURE ON THE ROLES OF EPIGENETIC MECHANISMS IN THE OCCURRENCE AND DEVELOPMENT OF INFLAMMATION-INDUCED CRC. EXPLORING THE ROLE OF EPIGENETICS IN THE TRANSFORMATION OF INFLAMMATION INTO CRC MAY HELP STIMULATE FUTURES STUDIES ON THE ROLE OF MOLECULAR THERAPY IN CRC. 2019 12 2036 37 EPIGENETIC CHANGES OF THE IMMUNE SYSTEM WITH ROLE IN TUMOR DEVELOPMENT. TUMOR DEVELOPMENT IS CLOSELY RELATED TO CHRONIC INFLAMMATION AND TO EVASION OF IMMUNE DEFENSE MECHANISMS BY NEOPLASTIC CELLS. THE MEDIATORS OF THE INFLAMMATORY PROCESS AS WELL AS PROTEINS INVOLVED IN IMMUNE RESPONSE OR IMMUNE RESPONSE EVASION CAN BE SUBJECT TO VARIOUS EPIGENETIC CHANGES SUCH AS METHYLATION, ACETYLATION, OR PHOSPHORYLATION. SOME OF THESE, SUCH AS CYTOKINE SUPPRESSORS, ARE UNDERGOING REPRESSION THROUGH EPIGENETIC CHANGES, AND OTHERS SUCH AS CYTOKINES OR CHEMOKINES ARE UNDERGOING ACTIVATION THROUGH EPIGENETIC CHANGES, BOTH MODIFICATIONS HAVING AS A RESULT TUMOR PROGRESSION. THE ACTIVATING CHANGES CAN AFFECT THE RECEPTOR MOLECULES INVOLVED IN IMMUNE RESPONSE AND THESE PROMOTE INFLAMMATION AND SUBSEQUENTLY TUMOR DEVELOPMENT WHILE THE INACTIVATING CHANGES SEEM TO BE RELATED TO THE TUMOR REGRESSION PROCESS. THE PROTEINS INVOLVED IN ANTIGEN PRESENTATION, AND, THEREFORE IN IMMUNE RESPONSE ESCAPE, SUCH AS CLASSICAL HLA PROTEINS AND RELATED APM (ANTIGEN PRESENTATION MACHINERY) WITH THEIR EPIGENETIC CHANGES CONTRIBUTE TO THE TUMOR DEVELOPMENT PROCESS, EITHER TO TUMOR PROGRESSION OR REGRESSION, DEPENDING ON THE IMMUNE EFFECTOR CELLS THAT ARE IN PLAY. 2018 13 6428 41 THE TUMOR MICROENVIRONMENT AND METASTATIC DISEASE. THE MICROENVIRONMENT OF SOLID TUMORS IS A HETEROGENEOUS, COMPLEX MILIEU FOR TUMOR GROWTH AND SURVIVAL THAT INCLUDES FEATURES SUCH AS ACIDIC PH, LOW NUTRIENT LEVELS, ELEVATED INTERSTITIAL FLUID PRESSURE (IFP) AND CHRONIC AND FLUCTUATING LEVELS OF OXYGENATION THAT RELATE TO THE ABNORMAL VASCULAR NETWORK THAT EXISTS IN TUMORS. THE METASTATIC POTENTIAL OF TUMOR CELLS IS BELIEVED TO BE REGULATED BY INTERACTIONS BETWEEN THE TUMOR CELLS AND THEIR EXTRACELLULAR ENVIRONMENT (EXTRACELLULAR MATRIX (ECM)). THESE INTERACTIONS CAN BE MODIFIED BY THE ACCUMULATION OF GENETIC CHANGES AND BY THE TRANSIENT ALTERATIONS IN GENE EXPRESSION INDUCED BY THE LOCAL TUMOR MICROENVIRONMENT. CLINICAL AND EXPERIMENTAL EVIDENCE SUGGESTS THAT ALTERED GENE EXPRESSION IN RESPONSE TO THE HYPOXIC MICROENVIRONMENT IS A CONTRIBUTING FACTOR TO INCREASED METASTATIC EFFICIENCY. A NUMBER OF GENES THAT HAVE BEEN IMPLICATED IN THE METASTATIC PROCESS, INVOLVING ANGIOGENESIS, INTRA/EXTRAVASATION, SURVIVAL AND GROWTH, HAVE BEEN FOUND TO BE HYPOXIA-RESPONSIVE. THE VARIOUS METASTATIC DETERMINANTS, GENETIC AND EPIGENETIC, SOMATIC AND INHERITED MAY SERVE AS PRECEDENTS FOR THE FUTURE IDENTIFICATION OF MORE GENES THAT ARE INVOLVED IN METASTASIS. MUCH RESEARCH HAS FOCUSED ON GENETIC AND MOLECULAR PROPERTIES OF THE TUMOR CELLS THEMSELVES. IN THE PRESENT REVIEW WE DISCUSS THE EPIGENETIC AND PHYSIOLOGICAL REGULATION OF METASTASIS AND EMPHASIZE THE NEED FOR FURTHER STUDIES ON THE INTERACTIONS BETWEEN THE PATHOPHYSIOLOGIC TUMOR MICROENVIRONMENT AND THE TUMOR EXTRACELLULAR MATRIX. 2009 14 928 29 CHRONIC INFLAMMATION, THE TUMOR MICROENVIRONMENT AND CARCINOGENESIS. CHRONIC INFLAMMATION OFTEN PRECEDES OR ACCOMPANIES A SUBSTANTIAL NUMBER OF CANCERS. INDEED, ANTI-INFLAMMATORY THERAPIES HAVE SHOWN EFFICACY IN CANCER PREVENTION AND TREATMENT. THE EXACT MECHANISMS THAT TURN A WOUND HEALING PROCESS INTO A CANCER PRECURSOR ARE TOPICS OF INTENSE RESEARCH. A PATHOGENIC LINK HAS BEEN IDENTIFIED BETWEEN INFLAMMATORY MEDIATORS, INFLAMMATION RELATED GENE POLYMORPHISMS AND CARCINOGENESIS. ANIMAL MODELS OF CANCER HAVE BEEN INSTRUMENTAL IN DEMONSTRATING THE DIVERSITY OF MECHANISMS THROUGH WHICH EVERY TUMOR COMPARTMENT AND TUMOR STAGE MAY BE AFFECTED BY THE UNDERLYING INFLAMMATORY PROCESS. IN THIS REVIEW, WE FOCUS ON THE INTERACTION BETWEEN CHRONIC INFLAMMATION, TUMOR STEM CELLS AND THE TUMOR MICROENVIRONMENT. WE SUMMARIZE THE PROPOSED MECHANISMS THAT LEAD TO THE RECRUITMENT OF BONE MARROW DERIVED CELLS AND EXPLORE THE GENETIC AND EPIGENETIC ALTERATIONS THAT MAY OCCUR IN INFLAMMATION ASSOCIATED CANCERS. 2009 15 3799 36 INTERPLAY BETWEEN INFLAMMATION AND EPIGENETIC CHANGES IN CANCER. IMMUNE RESPONSES CAN SUPPRESS TUMORIGENESIS, BUT ALSO CONTRIBUTE TO CANCER INITIATION AND PROGRESSION SUGGESTING A COMPLEX INTERACTION BETWEEN THE IMMUNE SYSTEM AND CANCER. EPIGENETIC ALTERATIONS, WHICH ARE HERITABLE CHANGES IN GENE EXPRESSION WITHOUT CHANGES TO THE DNA SEQUENCE, ALSO PLAY A ROLE IN CARCINOGENESIS THROUGH SILENCING EXPRESSION OF TUMOR SUPPRESSOR GENES AND ACTIVATING ONCOGENIC SIGNALING. INTERESTINGLY, EPITHELIAL CELLS AT SITES OF CHRONIC INFLAMMATION UNDERGO DNA METHYLATION ALTERATIONS THAT ARE SIMILAR TO THOSE PRESENT IN CANCER CELLS, SUGGESTING THAT INFLAMMATION MAY INITIATE CANCER-SPECIFIC EPIGENETIC CHANGES IN EPITHELIAL CELLS. FURTHERMORE, EPIGENETIC CHANGES OCCUR DURING IMMUNE CELL DIFFERENTIATION AND PARTICIPATE IN REGULATING THE IMMUNE RESPONSE, INCLUDING THE REGULATION OF INFLAMMATORY CYTOKINES. CANCER CELLS UTILIZE EPIGENETIC SILENCING OF IMMUNE-RELATED GENES TO EVADE THE IMMUNE RESPONSE. THIS CHAPTER WILL DETAIL THE INTERACTIONS BETWEEN INFLAMMATION AND EPIGENETICS IN TUMOR INITIATION, PROMOTION, AND IMMUNE EVASION AND HOW THESE CONNECTIONS ARE BEING LEVERAGED IN CANCER PREVENTION AND TREATMENT. 2016 16 2416 32 EPIGENETIC SIGNALING OF CANCER STEM CELLS DURING INFLAMMATION. MALIGNANT TUMORS POSE A GREAT CHALLENGE TO HUMAN HEALTH, WHICH HAS LED TO MANY STUDIES INCREASINGLY ELUCIDATING THE TUMORIGENIC PROCESS. CANCER STEM CELLS (CSCS) HAVE PROFOUND IMPACTS ON TUMORIGENESIS AND DEVELOPMENT OF DRUG RESISTANCE. RECENTLY, THERE HAS BEEN INCREASED INTEREST IN THE RELATIONSHIP BETWEEN INFLAMMATION AND CSCS BUT THE MECHANISM UNDERLYING THIS RELATIONSHIP HAS NOT BEEN FULLY ELUCIDATED. INFLAMMATORY CYTOKINES PRODUCED DURING CHRONIC INFLAMMATION ACTIVATE SIGNALING PATHWAYS THAT REGULATE THE GENERATION OF CSCS THROUGH EPIGENETIC MECHANISMS. IN THIS REVIEW, WE FOCUS ON THE EFFECTS OF INFLAMMATION ON CANCER STEM CELLS, PARTICULARLY THE ROLE OF SIGNALING PATHWAYS SUCH AS NF-KAPPAB PATHWAY, STAT3 PATHWAY AND SMAD PATHWAY INVOLVED IN REGULATING EPIGENETIC CHANGES. WE HOPE TO PROVIDE A NOVEL PERSPECTIVE FOR IMPROVING STRATEGIES FOR TUMOR TREATMENT. 2021 17 6201 38 THE INFLAMMATORY MICROENVIRONMENT AND MICROBIOME IN PROSTATE CANCER DEVELOPMENT. CHRONIC INFLAMMATION PROMOTES THE DEVELOPMENT OF SEVERAL TYPES OF SOLID CANCERS AND MIGHT CONTRIBUTE TO PROSTATE CARCINOGENESIS. THIS HYPOTHESIS PARTLY ORIGINATES IN THE FREQUENT OBSERVATION OF INFLAMMATORY CELLS IN THE PROSTATE MICROENVIRONMENT OF ADULT MEN. INFLAMMATION IS ASSOCIATED WITH PUTATIVE PROSTATE CANCER PRECURSOR LESIONS, TERMED PROLIFERATIVE INFLAMMATORY ATROPHY. INFLAMMATION MIGHT DRIVE PROSTATE CARCINOGENESIS VIA OXIDATIVE STRESS AND GENERATION OF REACTIVE OXYGEN SPECIES THAT INDUCE MUTAGENESIS. ADDITIONALLY, INFLAMMATORY STRESS MIGHT CAUSE EPIGENETIC ALTERATIONS THAT PROMOTE NEOPLASTIC TRANSFORMATION. PROLIFERATIVE INFLAMMATORY ATROPHY IS ENRICHED FOR PROLIFERATIVE LUMINAL EPITHELIAL CELLS OF INTERMEDIATE PHENOTYPE THAT MIGHT BE PRONE TO GENOMIC ALTERATIONS LEADING TO PROSTATIC INTRAEPITHELIAL NEOPLASIA AND PROSTATE CANCER. STUDIES IN ANIMALS SUGGEST THAT INFLAMMATORY CHANGES IN THE PROSTATE MICROENVIRONMENT CONTRIBUTE TO REPROGRAMMING OF PROSTATE EPITHELIAL CELLS, A POSSIBLE STEP IN TUMOUR INITIATION. PROSTATIC INFECTION, CONCURRENT WITH EPITHELIAL BARRIER DISRUPTION, MIGHT BE A KEY DRIVER OF AN INFLAMMATORY MICROENVIRONMENT; THE DISCOVERY OF A URINARY MICROBIOME INDICATES A POTENTIAL SOURCE OF FREQUENT EXPOSURE OF THE PROSTATE TO A DIVERSE NUMBER OF MICROORGANISMS. HENCE, CURRENT EVIDENCE SUGGESTS THAT INFLAMMATION AND ATROPHY ARE INVOLVED IN PROSTATE CARCINOGENESIS AND SUGGESTS A ROLE FOR THE MICROBIOME IN ESTABLISHING AN INFLAMMATORY PROSTATE MICROENVIRONMENT THAT MIGHT PROMOTE PROSTATE CANCER DEVELOPMENT AND PROGRESSION. 2018 18 6151 37 THE FIRE WITHIN: CELL-AUTONOMOUS MECHANISMS IN INFLAMMATION-DRIVEN CANCER. INFLAMMATORY CELLS ARE IMPORTANT FOR TUMOR INITIATION AND PROMOTION, PROVIDING CANCER CELLS WITH CYTOKINES THAT ENHANCE CELL PROLIFERATION AND SURVIVAL. ALTHOUGH MALIGNANT EPITHELIAL CELLS WERE TRADITIONALLY CONSIDERED TO BE ON THE RECEIVING END OF THESE MICROENVIRONMENTAL INTERACTIONS, RECENT STUDIES SHOW THAT EPITHELIAL CELLS CAN UNDERGO INFLAMMATORY REPROGRAMMING ON THEIR OWN. SUCH EPIGENETIC SWITCHES ARE OFTEN TRIGGERED BY CHRONIC TISSUE INJURY AND PLAY IMPORTANT ROLES IN TISSUE REPAIR. BY CONVERTING TERMINALLY DIFFERENTIATED CELLS THAT HARBOR EVEN A SINGLE ONCOGENIC MUTATION TO A LESS DIFFERENTIATED STATE WITH A HIGHER PROLIFERATIVE POTENTIAL, CELL-AUTONOMOUS INFLAMMATION IS AN IMPORTANT CONTRIBUTOR TO TUMOR INITIATION. 2019 19 1173 42 CONTRIBUTION OF TLR SIGNALING TO THE PATHOGENESIS OF COLITIS-ASSOCIATED CANCER IN INFLAMMATORY BOWEL DISEASE. IN THE INTESTINE A BALANCE BETWEEN PROINFLAMMATORY AND REPAIR SIGNALS OF THE IMMUNE SYSTEM IS ESSENTIAL FOR THE MAINTENANCE OF INTESTINAL HOMEOSTASIS. THE INNATE IMMUNITY ENSURES A PRIMARY HOST RESPONSE TO MICROBIAL INVASION, WHICH INDUCES AN INFLAMMATORY PROCESS TO LOCALIZE THE INFECTION AND PREVENT SYSTEMIC DISSEMINATION OF PATHOGENS. THE KEY ELEMENTS OF THIS PROCESS ARE THE GERMLINE ENCODED PATTERN RECOGNITION RECEPTORS INCLUDING TOLL-LIKE RECEPTORS (TLRS). IF PATHOGENS CANNOT BE ELIMINATED, THEY MAY ELICIT CHRONIC INFLAMMATION, WHICH MAY BE PARTLY MEDIATED VIA TLRS. ADDITIONALLY, CHRONIC INFLAMMATION HAS LONG BEEN SUGGESTED TO TRIGGER TISSUE TUMOROUS TRANSFORMATION. INFLAMMATION, THE SEVENTH HALLMARK OF CANCER, MAY AFFECT ALL PHASES OF TUMOR DEVELOPMENT, AND EVADE THE IMMUNE SYSTEM. INFLAMMATION ACTS AS A CELLULAR STRESSOR AND MAY TRIGGER DNA DAMAGE OR GENETIC INSTABILITY. FURTHERMORE, CHRONIC INFLAMMATION CAN PROVOKE GENETIC MUTATIONS AND EPIGENETIC MECHANISMS THAT PROMOTE MALIGNANT CELL TRANSFORMATION. COLORECTAL CANCERS IN INFLAMMATORY BOWEL DISEASE PATIENTS ARE CONSIDERED TYPICAL EXAMPLES OF INFLAMMATION-RELATED CANCERS. ALTHOUGH DATA REGARDING THE ROLE OF TLRS IN THE PATHOMECHANISM OF CANCER-ASSOCIATED COLITIS ARE RATHER CONFLICTING, FUNCTIONALLY THESE MOLECULES CAN BE CLASSIFIED AS "LARGELY ANTITUMORIGENIC" AND "LARGELY PRO-TUMORIGENIC" WITH THE CAVEAT THAT THE UNDERLYING SIGNALING PATHWAYS ARE MAINLY CONTEXT (I.E., ORGAN-, TISSUE-, CELL-) AND LIGAND-DEPENDENT. 2014 20 2854 43 FROM HEPATITIS TO HEPATOCELLULAR CARCINOMA: A PROPOSED MODEL FOR CROSS-TALK BETWEEN INFLAMMATION AND EPIGENETIC MECHANISMS. INFLAMMATION REPRESENTS THE BODY'S NATURAL RESPONSE TO TISSUE DAMAGE; HOWEVER, CHRONIC INFLAMMATION MAY ACTIVATE CELL PROLIFERATION AND INDUCE DEREGULATION OF CELL DEATH IN AFFECTED TISSUES. CHRONIC INFLAMMATION IS AN IMPORTANT FACTOR IN THE DEVELOPMENT OF HEPATOCELLULAR CARCINOMA (HCC), ALTHOUGH THE PRECISE UNDERLYING MECHANISM REMAINS UNKNOWN. EPIGENETIC EVENTS, WHICH ARE CONSIDERED KEY MECHANISMS IN THE REGULATION OF GENE ACTIVITY STATES, ARE ALSO COMMONLY DEREGULATED IN HCC. HERE, WE REVIEW THE EVIDENCE THAT CHRONIC INFLAMMATION MIGHT DEREGULATE EPIGENETIC PROCESSES, THUS PROMOTING ONCOGENIC TRANSFORMATION, AND WE PROPOSE A WORKING HYPOTHESIS THAT EPIGENETIC DEREGULATION IS AN UNDERLYING MECHANISM BY WHICH INFLAMMATION MIGHT PROMOTE HCC DEVELOPMENT. IN THIS SCENARIO, DIFFERENT COMPONENTS OF THE INFLAMMATORY RESPONSE MIGHT DIRECTLY AND INDIRECTLY INDUCE CHANGES IN EPIGENETIC MACHINERIES ('EPIGENETIC SWITCH'), INCLUDING THOSE INVOLVED IN SETTING AND PROPAGATING NORMAL PATTERNS OF DNA METHYLATION, HISTONE MODIFICATIONS AND NON-CODING RNAS IN HEPATOCYTES. WE DISCUSS THE POSSIBILITY THAT SELF-REINFORCING CROSS-TALK BETWEEN INFLAMMATION AND EPIGENETIC MECHANISMS MIGHT AMPLIFY INFLAMMATORY SIGNALS AND MAINTAIN A CHRONIC STATE OF INFLAMMATION CULMINATING IN CANCER DEVELOPMENT. THE POTENTIAL ROLE OF INFLAMMATION-EPIGENOME INTERACTIONS IN THE EMERGENCE AND MAINTENANCE OF CANCER STEM CELLS IS ALSO DISCUSSED. 2012