1 835 146 CHEMICAL CARCINOGEN MECHANISMS OF ACTION AND IMPLICATIONS FOR TESTING METHODOLOGY. CHEMICAL CARCINOGENS ARE OF TWO DISTINCT TYPES, DNA-REACTIVE AND EPIGENETIC. TESTING METHODOLOGY CAN BE DIRECTED TOWARD DETECTING EFFECTS OF BOTH TYPES OF CARCINOGEN. CARCINOGENS OF THE DNA-REACTIVE TYPE ARE DEFINED BY THE FORMATION OF COVALENTLY BOUND DNA ADDUCTS. THESE CHEMICALS HAVE STRUCTURES THAT YIELD ELECTROPHILIC REACTANTS EITHER DIRECTLY OR AFTER BIOACTIVATION. THESE AGENTS CAUSE GENOMIC ALTERATION IN THE STRUCTURE OR FUNCTION OF DNA IN THE TARGET CELL. IN ADDITION, THESE COMPOUNDS CAN EXERT OTHER CELLULAR AND TISSUE EPIGENETIC EFFECTS, SUCH AS CELL PROLIFERATION AND GROWTH PROMOTION. CARCINOGENS OF THE EPIGENETIC (PARAGENETIC) TYPE, IN CONTRAST, DO NOT REACT WITH DNA, BUT RATHER DISPLAY CELLULAR EFFECTS SUCH AS NEOPLASM GROWTH PROMOTION, CYTOTOXICITY, INHIBITION OF TISSUE GROWTH REGULATION, PEROXISOME PROLIFERATION, ENDOCRINE MODIFICATION, IMMUNOSUPPRESSION AND/OR SUSTAINED TISSUE ISCHEMIA THAT CAN BE THE BASIS FOR INCREASES IN NEOPLASIA. THEIR CHEMICAL STRUCTURE IS SUCH THAT THEY DO NOT GIVE RISE TO A REACTIVE ELECTROPHILE. THE TESTING METHODOLOGIES TO IDENTIFY EITHER TYPE FOLLOW A DECISION POINT APPROACH DESIGNED TO IDENTIFY POTENTIAL CARCINOGENICITY AND YIELD MECHANISTIC INFORMATION ON THE PRODUCTION OF EFFECTS THAT UNDERLIE CARCINOGENICITY. IT HAS 5 STAGES FOCUSING ON THE CHEMICAL STRUCTURE, DNA-REACTIVITY, EPIGENETIC EFFECTS, LIMITED BIOASSAYS AND FINALLY THE APPLICATION OF THE ACCELERATED BIOASSAY (ABA). ABA REQUIRES 40 WEEKS AND APPLIES THE USE OF SENSITIVE MARKERS FOR INDUCTION OF NEOPLASIA IN COMPARISON TO POSITIVE CONTROL COMPOUNDS FOR IMPORTANT ORGANS IN HUMAN CARCINOGENESIS. IT ENABLES DATA ACQUISITION OF THE ENTIRE CARCINOGENIC PROCESS DIRECTED TOWARD DEVELOPING MECHANISTIC INFORMATION. THE ABA HAS THE POTENTIAL TO REPLACE THE CHRONIC BIOASSAY IN RODENTS IN SOME CIRCUMSTANCES AND CAN SERVE AS AN ALTERNATIVE TO A CHRONIC BIOASSAY IN A SECOND SPECIES. 1996 2 5282 37 PROMOTION OF HEPATOCARCINOGENESIS IN HUMANS AND ANIMAL MODELS. RISK ASSESSMENT BASED ON RODENT CARCINOGENICITY DATA DEPENDS ON THE ASSUMPTION OF SIMILARITY BETWEEN RODENTS AND HUMANS. WHILE THIS ASSUMPTION IS CONCEIVABLE IN THE CASE OF GENOTOXIC INITIATING CARCINOGENS, CONSIDERABLE SPECIES DIFFERENCES HAVE BEEN OBSERVED WITH NONGENOTOXIC TUMOR PROMOTERS. THIS HETEROGENEOUS GROUP OF AGENTS INCREASES THE PROBABILITY OF CANCER BY STIMULATING SELECTION AND CLONAL EXPANSION OF CELLS TRANSFORMED DURING TUMOR INITIATION. SINCE TUMOR PROMOTERS DIFFERENTIALLY AFFECT NORMAL TISSUE AND PRENEOPLASTIC CELL CLONES, THEIR ACTION CANNOT BE DISCUSSED WITHOUT KNOWLEDGE OF PERSISTENT GENOMIC AND EPIGENETIC ALTERATIONS OCCURRING DURING INITIATION AND FORMATION OF PRENEOPLASTIC CELLS. CHEMICAL CARCINOGENESIS, AND IN PARTICULAR, TUMOR PROMOTION, IS KNOWN TO BE TISSUE SPECIFIC. WE FOCUS ON HEPATOCARCINOGENESIS IN HUMANS AND IN ANIMAL MODELS AND EMPHASIZE TWO DIFFERENT MODES OF ACTION: (1) CHRONIC CYTOTOXICITY LEADING TO PROMOTION OF LIVER CARCINOGENESIS IN BOTH HUMANS AND ANIMAL MODELS; (2) SUSTAINED ACTIVATION OF ORPHAN RECEPTORS SUCH AS CAR, PPARALPHA AND AH RECEPTOR LEADING TO PROMOTION OF RODENT BUT PROBABLY NOT HUMAN HEPATOCARCINOGENESIS. FURTHER STUDIES ON THE DIFFERENT MODES OF ACTION MAY HELP TO AVOID OVERESTIMATION OF THE RISK OF LIVER TUMOR PROMOTION. 2008 3 5493 24 REVIEW OF IN VITRO TEST SYSTEMS USING DNA DAMAGE AND REPAIR FOR SCREENING OF CHEMICAL CARCINOGENS. CHEMICAL CARCINOGENS ARE MECHANISTICALLY CLASSIFIED AS GENOTOXIC WHICH INTERACT DIRECTLY WITH DNA, AND EPIGENETIC WHICH CAUSE CHRONIC TISSUE INJURY, HORMONAL IMBALANCE, AND PROMOTIONAL EFFECTS. THIS REVIEW EVALUATES IN VITRO TESTS FOR THEIR CONTRIBUTION TO A BATTERY FOR IDENTIFYING GENOTOXIC CHEMICAL CARCINOGENS. IN ADDITION TO BACTERIAL MUTAGENIC ASSAYS, NONSPECIFIC DNA DAMAGE/REPAIR TESTS ARE RECOMMENDED FOR SCREENING CHEMICALS, IN PARTICULAR THE HEPATOCYTE PRIMARY CULTURE/DNA REPAIR TEST. 1979 4 3934 56 LIVER TUMOR INDUCTION. THE SIGNIFICANCE OF THE DEVELOPMENT OF NODULAR LIVER LESIONS IN RODENTS FOLLOWING THE ADMINISTRATION OF TEST AGENTS RAISES SEVERAL QUESTIONS WHICH COULD BE PLACED IN ONE OF TWO GENERAL CATEGORIES: DIAGNOSTIC AND INTERPRETATIONAL. FROM A DIAGNOSTIC POINT OF VIEW, THE PROPER CLASSIFICATION OF LIVER TUMORS INTO A BENIGN AND MALIGNANT CATEGORY HAS TO BE BASED ON THE DIRECT CORRELATION BETWEEN THE MORPHOLOGY AND THE BIOLOGIC BEHAVIOR OF THE LESIONS. THEREFORE, EXTREME CARE SHOULD BE TAKEN TO SEPARATE THE MALIGNANT TUMORS FROM THE BENIGN AND THE BENIGN NEOPLASIA FROM THE HYPERPLASIA. THE SUBSTITUTION OF THE TERM "NEOPLASTIC NODULE" FOR HYPERPLASTIC NODULE IN RATS IS MISLEADING. MOST OF THESE NODULES, WHEN INDUCED UNDER SPECIAL EXPERIMENTAL CONDITIONS, MAY REGRESS OR REMODEL AND THUS THEY ARE NOT NEOPLASTIC IN NATURE. CHRONIC CARCINOGENICITY BIOASSAYS SHOULD INCLUDE "STOP" TYPE OF TREATMENT LEAVING ENOUGH OF THE OBSERVATIONAL TIME TO ESTABLISH THE FATE OF INDUCED NODULAR LESIONS. THE INDUCTION OF HISTOCHEMICALLY CHANGED FOCI CAN SERVE ONLY AS AN INDICATION OF POTENTIAL HEPATOCARCINOGENICITY AND SHOULD NOT BE EQUATED WITH THE INDUCTION OF BONA FIDE CANCER. THE BIOLOGIC INTERPRETATION OF NODULAR LIVER LESIONS, ESPECIALLY IN MICE, NEEDS FURTHER SCRUTINY BECAUSE THESE LESIONS HAVE A TENDENCY TO DEVELOP SPONTANEOUSLY WITH HIGH INCIDENCE IN SOME STRAINS. THIS CHARACTERISTIC THEN RAISES THE QUESTION AS TO THE MECHANISM BY WHICH VARIOUS AGENTS AUGMENT AND/OR ACCELERATE THE DEVELOPMENT OF SUCH TUMORS. IS THIS ACTION PRIMARILY PROMOTING OR INITIATING IN NATURE OR DOES IT REPRESENT THE INDUCTION OF TUMORS DE NOVO? THE ANSWER TO THIS DILEMMA MAY HAVE A DECISIVE BEARING ON CARCINOGENIC RISK ASSESSMENT AND THE TYPE OF REGULATORY ACTION, SINCE THE PROMOTING AGENTS POSSESS A THRESHOLD EFFECT AND THE PROMOTED CHANGES MAY REGRESS FOLLOWING WITHDRAWAL OF TREATMENT. THE INTERPRETATION OF HEPATOCARCINOGENESIS IS FURTHER COMPLICATED BY THE FACT THAT SEVERAL FACTORS, SUCH AS SEX HORMONAL ENVIRONMENT, INCREASED MITOTIC ACTIVITY FOLLOWING AN EXCESSIVE LOSS OF PARENCHYMAL CELLS, DEGREE OF CALORIC INTAKE, ENZYMATIC COMPLEMENT, AND ANIMALS' AGE AT THE TIME OF THE EXPOSURE TO A TEST AGENT, MAY INFLUENCE THE OUTCOME OF LIVER TUMOR DEVELOPMENT BY MODULATING "INITIATION" AND/OR "PROMOTION" OF CARCINOGENESIS. BROAD FLUCTUATION IN THE HISTORIC INCIDENCE OF LIVER TUMORS FURTHER COMPOUNDS THE COMPLEXITY OF THE PROPER BIOASSAY INTERPRETATION. THE SPECIFICALLY DESIGNED EXPERIMENTS MAY HAVE THE OBJECTIVE TO EXPLORE PREDOMINANTLY THE INITIATING OR PROMOTING EFFECTS OF THE AGENT. SUCH PROTOCOLS SHOULD BE USED WHENEVER NECESSARY TO DIFFERENTIATE BETWEEN THESE TWO MECHANISMS OF ACTION. IN THE CAUCASIANS, THE "SPONTANEOUS" DEVELOPMENT OF THE PRIMARY HEPATOCELLULAR TUMORS IS RARE. THE MAJORITY OF THESE TUMORS ARE MALIGNANT AND RAPIDLY FATAL. ACCORDING TO SOME HUMAN PATHOLOGISTS, THE BENIGN VARIETY OF LIVER TUMORS IS RARE AND IT DOES NOT REPRESENT NECESSARILY A PREMALIGNANT STAGE IN TUMOR DEVELOPMENT. CARCINOMA OF THE LIVER MAY OCCUR IN INFANCY, ESPECIALLY IN MALES BEFORE THE AGE OF 2 YEARS. THIS SUGGESTS A GENETIC CAUSATION OR CARCINOGENIC EXPOSURE IN UTERO. ONE OF THE GEOGRAPHIC FACTORS WHICH SIGNIFICANTLY ENHANCES THE INCIDENCE OF HEPATOCELLULAR CARCINOMA IN HUMANS IS EXPOSURE TO AFLATOXIN B(1) WHICH IS APPARENTLY POTENTIATED BY CONCURRENT LIVER CIRRHOSIS. BECAUSE MANY MORE AGENTS HAVE BEEN FOUND TO BE HEPATOCARCINOGENIC IN MICE AND RATS THAN IN MEN, A QUESTION ARISES AS TO THE DIRECT RELEVANCE OF RODENT STUDIES TO HUMANS. A BALANCED ASSESSMENT OF THE CARCINOGENICITY OF THE AGENT COULD ONLY BE REACHED IN CONSIDERING BOTH THE PHARMACOKINETICS AND THE DEVELOPMENT OF MALIGNANT NEOPLASIA IN OTHER ORGANS. IN THE CASE OF POSITIVE CARCINOGENICITY ASSESSMENT, THE OUTCOME OF THE MUTAGENICITY BIOASSAYS CAN SUGGEST GENIC (GENOTOXIC) OR PARAGENIC (EPIGENETIC) MODE OF ACTION IN MAMMALIAN SYSTEMS. 1982 5 731 31 CANCER CHEMOPREVENTION: CLASSIC AND EPIGENETIC MECHANISMS INHIBITING TUMORIGENESIS. WHAT HAVE WE LEARNED SO FAR? CANCERS DERIVE FROM STEP BY STEP PROCESSES WHICH ARE DIFFERENTIATED BY THE PROGRESSIVELY ACCUMULATED MUTATIONS. FOR SOME TUMORS THERE IS A CLEAR PROGRESSIVE ADVANCEMENT FROM BENIGN LESIONS TO MALIGNANCY AND FOR THESE, PREVENTIVE SCREENING PROGRAMS EXIST. IN SUCH CASES HAVING THOSE BENIGN LESIONS ARE A CLEAR INDICATOR OF PREDISPOSITION WHILE FOR SOME OTHER CASES, FAMILIAL PATTERNS OF CANCER INCIDENCE AND THE IDENTIFICATION OF MUTATIONS ARE THE MAIN INDICATORS OF HIGHER RISK FOR HAVING THE DISEASE. FOR PATIENTS IDENTIFIED AS HAVING PREDISPOSITION, CHEMOPREVENTION IS A GOAL AND IN SOME CASES A POSSIBILITY. CHEMOPREVENTION IS THE USE OF ANY COMPOUND, EITHER NATURAL OR SYNTHETIC THAT ABROGATES CARCINOGENESIS OR TUMOR PROGRESSION, THROUGH DIFFERENT MECHANISMS, SOME OF WHICH HAVE ALREADY BEEN DESCRIBED. FOR EXAMPLE, THE CLASSIC MECHANISMS MAY INVOLVE ACTIVATION OF FREE RADICAL SCAVENGING ENZYMES, CONTROL OF CHRONIC INFLAMMATION, AND DOWNREGULATION OF SPECIFIC SIGNALING PATHWAYS. MORE RECENTLY, EPIGENETICS ALLOWED FURTHER UNDERSTANDING OF THE CHEMOPREVENTIVE POTENTIAL OF SEVERAL AGENTS, SUCH AS SULFORAPHANE, GREEN TEA DERIVED COMPOUNDS, RESVERATROL, ISOFLAVONES, AND OTHERS WHICH WE EXPLOIT IN THIS REVIEW ARTICLE. THROUGHOUT THE TEXT WE DISCUSS THE PROPERTIES COMPOUNDS SHOULD HAVE IN ORDER TO BE CLASSIFIED AS CHEMOPREVENTIVE ONES AND THE CHALLENGES IN TRANSLATIONAL RESEARCH IN THIS AREA, AS LOTS OF THE SUCCESS ACHIEVED IN VITRO CANNOT BE TRANSLATED INTO THE CLINICAL SETTINGS, DUE TO SEVERAL DIFFERENT DRAWBACKS, WHICH INCLUDE TOXICITY, COST, DOSE DEFINITION, PATIENT ADHERENCE, AND REGIMEN OF USE. 2018 6 1918 46 ENVIRONMENTAL CARCINOGENESIS AND TRANSGENERATIONAL TRANSMISSION OF CARCINOGENIC RISK: FROM GENETICS TO EPIGENETICS. THE DOMINANT PATHOGENIC MODEL, SOMATIC MUTATION THEORY (SMT), CONSIDERS CARCINOGENESIS AS A 'GENETIC ACCIDENT' DUE TO THE ACCUMULATION OF 'STOCHASTIC' DNA MUTATIONS. THIS MODEL WAS PROPOSED AND ACCEPTED BY THE SCIENTIFIC COMMUNITY WHEN CANCER MAINLY AFFECTED THE ELDERLY, BUT IT DOES NOT EXPLAIN THE EPIDEMIOLOGICAL OBSERVATION OF THE CONTINUOUS INCREASE IN CANCER INCIDENCE AMONG CHILDREN AND YOUNG ADULTS. SOMATIC MUTATION THEORY HAS BEEN PROPOSED FOR A REVISION BASED ON THE EMERGING EXPERIMENTAL EVIDENCE, AS IT DOES NOT FULLY ADDRESS SOME ISSUES THAT HAVE PROVEN TO BE CRUCIAL FOR CARCINOGENESIS, NAMELY: THE INFLAMMATORY CONTEXT OF CANCER; THE KEY ROLE PLAYED BY THE STROMA, MICROENVIRONMENT, ENDOTHELIAL CELLS, ACTIVATED MACROPHAGES, AND SURROUNDING TISSUES; AND THE DISTORTED DEVELOPMENTAL COURSE FOLLOWED BY THE NEOPLASTIC TISSUE. FURTHERMORE, SMT IS OFTEN NOT ABLE TO CONSIDER EITHER THE EXISTENCE OF SPECIFIC MUTATIONS RESULTING IN A WELL-DEFINED CANCER TYPE, OR A CLEAR RELATIONSHIP BETWEEN MUTATIONS AND TUMOR PROGRESSION. MOREOVER, IT DOES NOT EXPLAIN THE MECHANISM OF ACTION OF THE NON-MUTAGENIC AND ENVIRONMENTAL CARCINOGENS. IN THE LAST DECADE, CANCER RESEARCH HAS HIGHLIGHTED THE PROMINENT ROLE OF AN ALTERED REGULATION OF GENE EXPRESSION, SUGGESTING THAT CANCER SHOULD BE CONSIDERED AS A RESULT OF A POLYCLONAL EPIGENETIC DISRUPTION OF STEM/PROGENITOR CELLS, MEDIATED BY TUMOUR-INDUCING GENES. THE MATERNAL AND FETAL EXPOSURE TO A WIDE RANGE OF CHEMICALS AND ENVIRONMENTAL CONTAMINANTS IS RAISING THE ATTENTION OF THE SCIENTIFIC COMMUNITY. INDEED, THE MOST POWERFUL PROCARCINOGENIC MECHANISMS OF ENDOCRINE DISRUPTORS AND OTHER POLLUTANTS IS LINKED TO THEIR POTENTIAL TO INTERFERE EPIGENETICALLY WITH THE EMBRYO-FETAL PROGRAMMING OF TISSUES AND ORGANS, ALTERING THE REGULATION OF THE GENES INVOLVED IN THE CELL CYCLE, CELL PROLIFERATION, APOPTOSIS, AND OTHER KEY SIGNALING PATHWAYS. THE EMBRYO-FETAL EXPOSURE TO ENVIRONMENTAL, STRESSFUL, AND PROINFLAMMATORY TRIGGERS (FIRST HIT), SEEMS TO ACT AS A 'DISEASE PRIMER', MAKING FETAL CELLS AND TISSUES MORE SUSCEPTIBLE TO THE SUBSEQUENT ENVIRONMENTAL EXPOSURES (SECOND HIT), TRIGGERING THE CARCINOGENIC PATHWAYS. FURTHERMORE, EVEN AT THE MOLECULAR LEVEL, IN CARCINOGENESIS, 'EPIGENETICS PRECEDES GENETICS' AS GLOBAL DNA HYPOMETHYLATION, AND THE HYPERMETHYLATION OF TUMOR SUPPRESSOR GENES ARE COMMON BOTH IN CANCEROUS AND IN PRECANCEROUS CELLS, AND GENERALLY PRECEDE MUTATIONS. THESE EPIGENETIC MODELS MAY BETTER EXPLAIN THE INCREASE OF CANCER AND CHRONIC/DEGENERATIVE DISEASES IN THE LAST DECADES AND COULD BE USEFUL TO ADOPT APPROPRIATE PRIMARY PREVENTION MEASURES, ESSENTIALLY BASED ON THE REDUCTION OF MATERNAL-FETAL AND CHILD EXPOSURE TO SEVERAL PROCARCINOGENIC AGENTS AND FACTORS DISPERSED IN THE ENVIRONMENT AND IN THE FOOD-CHAINS, AS RECENTLY SUGGESTED BY THE WORLD HEALTH ORGANIZATION. 2018 7 2790 45 FACTORS TO CONSIDER IN THE USE OF STEM CELLS FOR PHARMACEUTIC DRUG DEVELOPMENT AND FOR CHEMICAL SAFETY ASSESSMENT. GIVEN THE REALITY OF THE INADEQUACIES OF CURRENT CONCEPTS OF THE MECHANISMS OF CHEMICAL TOXICITIES, OF THE VARIOUS ASSAYS TO PREDICT TOXICITIES FROM CURRENT MOLECULAR, BIOCHEMICAL, IN VITRO AND ANIMAL BIOASSAYS, AND OF THE FAILURE TO GENERATE EFFICACIOUS AND SAFE CHEMICALS FOR MEDICINES, FOOD SUPPLEMENTS, INDUSTRIAL, CONSUMER AND AGRICULTURAL CHEMICALS, THE RECENT NAS REPORT, "TOXICITY TESTING IN THE 21ST CENTURY: A VISION AND A STRATEGY", HAS DRAWN ATTENTION TO A RENEWED EXAMINATION OF WHAT NEEDS TO BE DONE TO IMPROVE OUR CURRENT APPROACH FOR BETTER ASSESSMENT OF POTENTIAL RISK TO HUMAN HEALTH. THIS "COMMENTARY" PROVIDES A MAJOR PARADIGM CHALLENGE TO THE CURRENT CONCEPTS OF HOW CHEMICALS INDUCE TOXICITIES AND HOW THESE VARIOUS MECHANISMS OF TOXICITIES CAN CONTRIBUTE TO THE PATHOGENESIS OF SOME HUMAN DISEASES, SUCH AS BIRTH DEFECTS AND CANCER. IN CONCORDANCE WITH THE NAS REPORT TO TAKE "... ADVANTAGE OF THE ON-GOING REVOLUTION IN BIOLOGY AND BIOTECHNOLOGY", THIS "COMMENTARY" SUPPORTS THE USE OF HUMAN EMBRYONIC AND ADULT STEM CELLS, GROWN IN VITRO UNDER SIMULATED "IN VIVO NICHE CONDITIONS". THE HUMAN BEING SHOULD BE VIEWED "AS GREATER THAN THE SUM OF ITS PARTS". HOMEOSTATIC CONTROL OF THE "EMERGENT PROPERTIES" OF THE HUMAN HIERARCHY, NEEDED TO MAINTAIN HUMAN HEALTH, REQUIRES COMPLEX INTEGRATION OF ENDOGENOUS AND EXOGENOUS SIGNALING MOLECULES THAT CONTROL CELL PROLIFERATION, DIFFERENTIATION, APOPTOSIS AND SENESCENCE OF STEM, PROGENITOR AND DIFFERENTIATED CELLS. CURRENTLY, IN VITRO TOXICITY ASSAYS (MUTAGENESIS, CYTOTOXICITY, EPIGENETIC MODULATION), DONE ON 2-DIMENSIONAL PRIMARY RODENT OR HUMAN CELLS (WHICH ARE ALWAYS MIXTURES OF CELLS), ON IMMORTALIZED OR TUMORIGENIC RODENT OR HUMAN CELL LINES DO NOT REPRESENT NORMAL HUMAN CELLS IN VIVO [WHICH DO NOT GROW ON PLASTIC AND WHICH ARE IN MICRO-ENVIRONMENTS REPRESENTING 3 DIMENSIONS AND CONSTANTLY INTERACTING FACTORS]. IN ADDITION, WITH THE KNOWN GENETIC, GENDER, AND DEVELOPMENTAL STATE OF CELLS IN VIVO, ANY IN VITRO TOXICITY ASSAY WILL NEED TO MIMIC THESE CONDITIONS IN VITRO. MORE SPECIFICALLY, WHILE TISSUES CONTAIN A FEW STEM CELLS, MANY PROGENITOR/TRANSIT CELLS AND TERMINALLY DIFFERENTIATED CELLS, IT SHOULD BE OBVIOUS THAT BOTH EMBRYONIC AND ADULT STEM CELLS WOULD BE CRITICAL "TARGET" CELLS FOR TOXICITY TESTING. THE ULTIMATE POTENTIAL FOR IN VITRO TESTING OF HUMAN STEM CELLS WILL TO TRY TO MIMIC A 3-D IN VITRO MICRO-ENVIRONMENT ON MULTIPLE "ORGAN-SPECIFIC AND MULTIPLE GENOTYPIC/GENDER "ADULT STEM CELLS. THE ROLE OF STEM CELLS IN MANY CHRONIC DISEASES, SUCH AS CANCER, BIRTH DEFECTS, AND POSSIBLY ADULT DISEASES AFTER PRE-NATAL AND EARLY POST-NATAL EXPOSURES (BARKER HYPOTHESIS), DEMANDS TOXICITY STUDIES OF STEM CELLS. WHILE ALTERATION OF GENE EXPRESSION ("TOXICO-EPIGENOMICS") IS A LEGITIMATE ENDPOINT OF THESE TOXICITY STUDIES, ALTERATION OF THE QUANTITY OF STEM CELLS DURING DEVELOPMENT MUST BE SERIOUS CONSIDERED. IF THE FUTURE UTILITY OF HUMAN STEM CELLS PROVES TO BE VALID, THE ELIMINATION OF LESS RELEVANT, EXPENSIVE AND TIME-CONSUMING RODENT AND 2-D HUMAN IN VITRO ASSAYS WILL BE ELIMINATED. 2010 8 3697 35 INFLAMMATORY MARKERS IN CANCER: POTENTIAL RESOURCES. CANCER IS A LEADING CAUSE OF DEATH WORLDWIDE AND A MAJOR BURDEN ON DEVELOPING AND LESS DEVELOPED COUNTRIES OF THE WORLD WITH LIMITED RESOURCES FOR PREVENTION AND EFFECTIVE TREATMENT OF CANCER. ALTHOUGH CANCER IS MULTIFACTORIAL IN ORIGIN, VARIOUS EPIDEMIOLOGICAL AND EXPERIMENTAL STUDIES SUGGEST THAT CHRONIC INFLAMMATION HAS AN IMPORTANT ROLE IN ALL STAGES OF CANCER, FROM INITIATION TO PROGRESSION AND EVEN SURVIVAL OF THE PATIENT. INFLAMMATORY PRODUCTS LIKE CYTOKINES, CHEMOKINES, LEUCOCYTES, PROSTAGLANDINS, CYCLOOXYGENASE, REACTIVE OXYGEN AND NITROGEN SPECIES, METALLOPROTEINASE INDUCE GENETIC AND EPIGENETIC CHANGES IN NORMAL CELLS DAMAGING ITS DNA, INHIBITING ITS REPAIR, ALTERING TRANSCRIPTION FACTORS, PREVENTING APOPTOSIS, AND STIMULATING ANGIOGENESIS, AND THUS RESULTING IN CARCINOGENESIS. THUS, THESE INFLAMMATORY MEDIATORS HAVE A POTENTIAL ROLE TO BECOME CANCER BIOMARKERS FOR ALL STAGES OF CANCER AS MANY OF THEM CAN BE MEASURED IN A COST-EFFECTIVE MANNER. HOWEVER, LARGE SCALE PROSPECTIVE TRIALS ARE REQUIRED TO VALIDATE THESE POTENTIAL CANCER BIOMARKERS. NONETHELESS, A TRANSITION FROM POTENTIAL TO PRACTICAL UTILIZATION OF THESE MARKERS WILL BE AN EFFECTIVE TOOL FOR THE AMELIORATION OF CANCER BURDEN AND MORTALITY IN A RESOURCE LIMITED SETTING. 2020 9 1010 30 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 10 737 49 CANCER STEM CELLS. THERE IS AN INCREASING EVIDENCE SUPPORTING THE CANCER STEM CELL HYPOTHESIS. NORMAL STEM CELLS IN THE ADULT ORGANISM ARE RESPONSIBLE FOR TISSUE RENEWAL AND REPAIR OF AGED OR DAMAGED TISSUE. A SUBSTANTIAL CHARACTERISTIC OF STEM CELLS IS THEIR ABILITY FOR SELF-RENEWAL WITHOUT LOSS OF PROLIFERATION CAPACITY WITH EACH CELL DIVISION. THE STEM CELLS ARE IMMORTAL, AND RATHER RESISTANT TO ACTION OF DRUGS. THEY ARE ABLE TO DIFFERENTIATE AND FORM SPECIFIC TYPES OF TISSUE DUE TO THE INFLUENCE OF MICROENVIRONMENTAL AND SOME OTHER FACTORS. STEM CELLS DIVIDE ASYMMETRICALLY PRODUCING TWO DAUGHTER CELLS -- ONE IS A NEW STEM CELL AND THE SECOND IS PROGENITOR CELL, WHICH HAS THE ABILITY FOR DIFFERENTIATION AND PROLIFERATION, BUT NOT THE CAPABILITY FOR SELF-RENEWAL. CANCER STEM CELLS ARE IN MANY ASPECTS SIMILAR TO THE STEM CELLS. IT HAS BEEN PROVEN THAT TUMOR CELLS ARE HETEROGENEOUS COMPRISING RARE TUMOR INITIATING CELLS AND ABUNDANT NON-TUMOR INITIATING CELLS. TUMOR INITIATING CELLS -- CANCER STEM CELLS HAVE THE ABILITY OF SELF-RENEWAL AND PROLIFERATION, ARE RESISTANT TO DRUGS, AND EXPRESS TYPICAL MARKERS OF STEM CELLS. IT IS NOT CLEAR WHETHER CANCER STEM CELLS ORIGINATE FROM NORMAL STEM CELLS IN CONSEQUENCE OF GENETIC AND EPIGENETIC CHANGES AND/OR BY REDIFFERENTIATION FROM SOMATIC TUMOR CELLS TO THE STEM-LIKE CELLS. PROBABLY BOTH MECHANISMS ARE INVOLVED IN THE ORIGIN OF CANCER STEM CELLS. DYSREGULATION OF STEM CELL SELF-RENEWAL IS A LIKELY REQUIREMENT FOR THE DEVELOPMENT OF CANCER. ISOLATION AND IDENTIFICATION OF CANCER STEM CELLS IN HUMAN TUMORS AND IN TUMOR CELL LINES HAS BEEN SUCCESSFUL. TO DATE, THE EXISTENCE OF CANCER STEM CELLS HAS BEEN PROVEN IN ACUTE AND CHRONIC MYELOID LEUKEMIA, IN BREAST CANCER, IN BRAIN TUMORS, IN LUNG CANCER AND GASTROINTESTINAL TUMORS. CANCER STEM CELL MODEL IS ALSO CONSISTENT WITH SOME CLINICAL OBSERVATIONS. ALTHOUGH STANDARD CHEMOTHERAPY KILLS MOST CELLS IN A TUMOR, CANCER STEM CELLS REMAIN VIABLE. DESPITE THE SMALL NUMBER OF SUCH CELLS, THEY MIGHT BE THE CAUSE OF TUMOR RECURRENCE, SOMETIMES MANY YEARS AFTER THE "SUCCESSFUL" TREATMENT OF PRIMARY TUMOR. GROWTH OF METASTASES IN DISTINCT AREAS OF BODY AND THEIR CELLULAR HETEROGENEITY MIGHT BE CONSEQUENCE OF CANCER STEM CELL DIFFERENTIATION AND/OR DEDIFFERENTIATION AND ASYMMETRIC DIVISION OF CANCER STEM CELLS. FURTHER CHARACTERIZATION OF CANCER STEM CELLS IS NEEDED IN ORDER TO FIND WAYS TO DESTROY THEM, WHICH MIGHT CONTRIBUTE SIGNIFICANTLY TO THE THERAPEUTIC MANAGEMENT OF MALIGNANT TUMORS. 2005 11 6031 28 THE CANCER EPIGENOME: ITS ORIGINS, CONTRIBUTIONS TO TUMORIGENESIS, AND TRANSLATIONAL IMPLICATIONS. EPIGENETIC ABNORMALITIES IN LUNG AND OTHER CANCERS CONTINUE TO BE DEFINED AT A RAPID PACE. WE ARE COMING TO APPRECIATE THAT CANCERS HAVE AN "EPIGENETIC LANDSCAPE" WHEREIN GENES VULNERABLE TO ABNORMALITIES, SUCH AS PROMOTER DNA HYPERMETHYLATION AND ASSOCIATED GENE SILENCING, TEND TO RESIDE IN DEFINED NUCLEAR POSITIONS AND CHROMOSOME DOMAINS AND RELATIONSHIPS TO CHROMATIN REGULATION, WHICH FACILITATES STATES OF STEM CELL RENEWAL. THESE SAME GENES AND DOMAINS ARE ALSO VULNERABLE TO EPIGENETIC ABNORMALITIES INDUCED BY FACTORS TO WHICH CELLS ARE EXPOSED DURING CANCER RISK STATES, SUCH AS CHRONIC INFLAMMATION. WE CAN USE ALL OF THIS BASIC INFORMATION FOR TRANSLATIONAL PURPOSES IN TERMS OF DERIVING BIOMARKERS FOR CANCER RISK STATES AND DETECTION AND THERAPEUTIC STRATEGIES. 2012 12 186 30 ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS IN NORMAL CELLS AND CANCER RISK. CANCERS DEVELOP DUE TO THE ACCUMULATION OF GENETIC AND EPIGENETIC ALTERATIONS. GENETIC ALTERATIONS ARE INDUCED BY AGING, MUTAGENIC CHEMICALS, ULTRAVIOLET LIGHT, AND OTHER FACTORS; WHEREAS, EPIGENETIC ALTERATIONS ARE MAINLY BY AGING AND CHRONIC INFLAMMATION. THE ACCUMULATION AND PATTERNS OF ALTERATIONS IN NORMAL CELLS REFLECT OUR PAST EXPOSURE LEVELS AND LIFE HISTORY. MOST ACCUMULATED ALTERATIONS ARE CONSIDERED AS PASSENGERS, BUT THEIR ACCUMULATION IS CORRELATED WITH CANCER DRIVERS. THIS HAS BEEN SHOWN FOR ABERRANT DNA METHYLATION BUT HAS ONLY BEEN SPECULATED FOR GENETIC ALTERATIONS. HOWEVER, RECENT TECHNOLOGICAL ADVANCEMENTS HAVE ENABLED MEASUREMENT OF RARE POINT MUTATIONS, AND STUDIES HAVE SHOWN THAT THEIR ACCUMULATION LEVELS ARE INDEED CORRELATED WITH CANCER RISK. WHEN THE ACCUMULATION LEVELS OF ABERRANT DNA METHYLATION AND POINT MUTATIONS ARE COMBINED, RISK PREDICTION BECOMES EVEN MORE ACCURATE. WHEN HIGH LEVELS OF ALTERATIONS ACCUMULATE, THE TISSUE HAS A HIGH RISK OF DEVELOPING CANCER OR EVEN MULTIPLE CANCERS AND IS CONSIDERED AS A "CANCERIZATION FIELD", WITH OR WITHOUT EXPANSION OF PHYSIOLOGICAL PATCHES OF CLONAL CELLS. IN THIS REVIEW, WE DESCRIBE THE FORMATION OF A CANCERIZATION FIELD AND HOW WE CAN APPLY ITS DETECTION IN PRECISION CANCER RISK DIAGNOSIS. 2019 13 4429 38 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 14 6842 26 [MECHANISTIC ISSUES AND PREVENTION STRATEGIES TARGETING OCCUPATIONAL CARCINOGENESIS]. CARCINOGENESIS CAN BE VISUALIZED EITHER AS A MULTISTEP PROCESS (INITIATION, PROMOTION, PROGRESSION, INVASION, AND METASTASIS) OR AS A CONTINUUM OF MUTAGENIC AND MITOGENIC EVENTS, WITH THE CONTRIBUTION OF EPIGENETIC MECHANISMS. THE EXPONENTIAL GROWTH OF THE NEOPLASTIC MASS EXPLAINS THE IMPORTANCE OF SECONDARY PREVENTION (EARLY DIAGNOSIS) AND OF TERTIARY PREVENTION. PRIMARY PREVENTION, WHICH WAS SUCCESSFUL IN CONTROLLING OCCUPATIONAL CANCERS, AIMS AT MINIMIZING EXPOSURES TO CARCINOGENS IN HEALTHY SUBJECTS AND AT FAVORING THE INTAKE OF CHEMOPREVENTIVE AGENTS WITH DIETARY AND PHARMACOLOGICAL AGENTS. BESIDES CHEMICAL CARCINOGENS, OFTEN IN THE FORM OF COMPLEX MIXTURES, THE WORKPLACE MAY INVOLVE EXPOSURES TO PHYSICAL AGENTS, SUCH AS SUNLIGHT AND ARTIFICIAL ILLUMINATION SYSTEMS DELIVERING UV RADIATION, OR TO BIOLOGICAL AGENTS, SUCH AS CHRONIC VIRAL INFECTIONS (HBV, HCV, AND HIV) ASSOCIATED WITH CANCERS. A CONTROVERSIAL ISSUE IS THE OCCURRENCE OF THRESHOLD DOSES FOR CARCINOGENS IN THE WORKPLACE AND THE ENVIRONMENT. 2011 15 733 35 CANCER EPIGENETICS: LINKING BASIC BIOLOGY TO CLINICAL MEDICINE. CANCER EVOLUTION AT ALL STAGES IS DRIVEN BY BOTH EPIGENETIC ABNORMALITIES AS WELL AS GENETIC ALTERATIONS. DYSREGULATION OF EPIGENETIC CONTROL EVENTS MAY LEAD TO ABNORMAL PATTERNS OF DNA METHYLATION AND CHROMATIN CONFIGURATIONS, BOTH OF WHICH ARE CRITICAL CONTRIBUTORS TO THE PATHOGENESIS OF CANCER. THESE EPIGENETIC ABNORMALITIES ARE SET AND MAINTAINED BY MULTIPLE PROTEIN COMPLEXES AND THE INTERPLAY BETWEEN THEIR INDIVIDUAL COMPONENTS INCLUDING DNA METHYLATION MACHINERY, HISTONE MODIFIERS, PARTICULARLY, POLYCOMB (PCG) PROTEINS, AND CHROMATIN REMODELING PROTEINS. RECENT ADVANCES IN GENOME-WIDE TECHNOLOGY HAVE REVEALED THAT THE INVOLVEMENT OF THESE DYSREGULATED EPIGENETIC COMPONENTS APPEARS TO BE EXTENSIVE. MOREOVER, THERE IS A GROWING CONNECTION BETWEEN EPIGENETIC ABNORMALITIES IN CANCER AND CONCEPTS CONCERNING STEM-LIKE CELL SUBPOPULATIONS AS A DRIVING FORCE FOR CANCER. EMERGING DATA SUGGEST THAT ASPECTS OF THE EPIGENETIC LANDSCAPE INHERENT TO NORMAL EMBRYONIC AND ADULT STEM/PROGENITOR CELLS MAY HELP FOSTER, UNDER THE STRESS OF CHRONIC INFLAMMATION OR ACCUMULATING REACTIVE OXYGEN SPECIES, EVOLUTION OF MALIGNANT SUBPOPULATIONS. FINALLY, UNDERSTANDING MOLECULAR MECHANISMS INVOLVED IN INITIATION AND MAINTENANCE OF EPIGENETIC ABNORMALITIES IN ALL TYPES OF CANCER HAS GREAT POTENTIAL FOR TRANSLATIONAL PURPOSES. THIS IS ALREADY EVIDENT FOR EPIGENETIC BIOMARKER DEVELOPMENT, AND FOR PHARMACOLOGICAL TARGETING AIMED AT REVERSING CANCER-SPECIFIC EPIGENETIC ALTERATIONS. 2011 16 6449 38 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 17 6428 31 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 18 1844 36 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 19 3683 42 INFLAMMATION, MICROBIOTA, AND PROSTATE CANCER. CONTEXT: CHRONIC INFLAMMATION OF THE PROSTATE HAS BEEN ASSOCIATED WITH PRENEOPLASTIC LESIONS AND CANCER DEVELOPMENT. MULTIPLE CAUSES HAVE BEEN CONSIDERED FOR CHRONIC INFLAMMATION OF THE PROSTATE. INFLAMMATORY CYTOKINES SUCH AS INTERLEUKINS ARE IMPLICATED IN PROSTATE CARCINOGENESIS AND DEVELOPMENT. OBJECTIVE: TO EVALUATE LITERATURE PUBLISHED ON ETIOLOGICAL FACTORS, URINARY MICROBIOTA, MORPHOLOGICAL FEATURES OF PROLIFERATIVE INFLAMMATORY ATROPHY AND HIGH-GRADE PROSTATE INTRAEPITHELIAL NEOPLASIA, GENETIC POLYMORPHISMS, INFLAMMATORY STRESS, AND CYTOKINE SIGNALING. EVIDENCE ACQUISITION: WE SEARCHED LITERATURE FROM PUBMED FROM 2010 AND ALSO INCLUDED THE MOST IMPORTANT PUBLICATIONS FROM THE PREVIOUS PERIOD. EVIDENCE SYNTHESIS: PROSTATE CANCER INFLAMMATION AND PREMALIGNANT LESIONS HAVE BEEN FREQUENTLY DISCUSSED IN SCIENTIFIC LITERATURE. A LIMITED NUMBER OF MODELS ARE AVAILABLE FOR STUDYING INFLAMMATION AND PREMALIGNANT LESIONS. HOWEVER, MORPHOLOGICAL PATHOLOGY COULD BE COMPLEMENTED BY ANALYSIS OF GENE POLYMORPHISMS IN THESE PATIENTS AND APPROPRIATE FUNCTIONAL STUDIES. CONCLUSIONS: PROSTATITIS COULD BE CAUSED BY BACTERIAL OR VIRAL INFECTIONS, DIETARY COMPOUNDS, AND CHANGES IN TESTOSTERONE:ESTRADIOL RATIO. IN SOME CASES, THE MICROBIOTA CAN EXERT DIRECT EFFECTS ON CANCER DEVELOPMENT. PROSTATE INFLAMMATORY ATROPHY OR HIGH GRADE PROSTATE INTRAEPITHELIAL NEOPLASIA HAVE BEEN ASSOCIATED WITH RESPONSE TO CELLULAR STRESS AND HAVE BEEN DISCUSSED IN CONNECTION TO EARLY CANCER DEVELOPMENT. A LARGE NUMBER OF GENETIC POLYMORPHISMS HAVE BEEN IDENTIFIED IN INFLAMMATORY PROSTATE. GENETIC AND EPIGENETIC ALTERATIONS MAY BE A CONSEQUENCE OF THE PROINFLAMMATORY STRESS IN THE PROSTATE. PROINFLAMMATORY CYTOKINES INTERLEUKIN-6 AND -8 CONTRIBUTE TO PROSTATE MALIGNANCY; HOWEVER, THEIR FUNCTION WAS MORE FREQUENTLY INVESTIGATED IN CANCER TISSUE RATHER THAN IN INFLAMMATION. PATIENT SUMMARY: WE PERFORMED A REVIEW OF RECENT LITERATURE RELATED TO PROSTATE INFLAMMATION, MICROBIOTA, AND PROSTATE CANCER. NEW FUNCTIONAL APPROACHES ARE REQUIRED FOR A BETTER UNDERSTANDING OF THE ROLE OF INFLAMMATION AND CANCER DEVELOPMENT. 2016 20 5373 36 RECENT ADVANCES IN UNDERSTANDING THE ROLE OF DIET AND OBESITY IN THE DEVELOPMENT OF COLORECTAL CANCER. COLORECTAL CANCER (CRC) IS A MAJOR CAUSE OF PREMATURE DEATH IN THE UK AND MANY DEVELOPED COUNTRIES. HOWEVER, THE RISK OF DEVELOPING CRC IS WELL RECOGNISED TO BE ASSOCIATED NOT ONLY WITH DIET BUT ALSO WITH OBESITY AND LACK OF EXERCISE. WHILE EPIDEMIOLOGICAL EVIDENCE SHOWS AN ASSOCIATION WITH FACTORS SUCH AS HIGH RED MEAT INTAKE AND LOW INTAKE OF VEGETABLES, FIBRE AND FISH, THE MECHANISMS UNDERLYING THESE EFFECTS ARE ONLY NOW BEING ELUCIDATED. CRC DEVELOPS OVER MANY YEARS AND IS TYPICALLY CHARACTERISED BY AN ACCUMULATION OF MUTATIONS, WHICH MAY ARISE AS A CONSEQUENCE OF INHERITED POLYMORPHISMS IN KEY GENES, BUT MORE COMMONLY AS A RESULT OF SPONTANEOUSLY ARISING MUTATIONS AFFECTING GENES CONTROLLING CELL PROLIFERATION, DIFFERENTIATION, APOPTOSIS AND DNA REPAIR. EPIGENETIC CHANGES ARE OBSERVED THROUGHOUT THE PROGRESS FROM NORMAL MORPHOLOGY THROUGH FORMATION OF ADENOMA, AND THE SUBSEQUENT DEVELOPMENT OF CARCINOMA. THE REASONS WHY THIS ACCUMULATION OF LOSS OF HOMOEOSTATIC CONTROLS ARISES ARE UNCLEAR BUT CHRONIC INFLAMMATION HAS BEEN PROPOSED TO PLAY A CENTRAL ROLE. OBESITY IS ASSOCIATED WITH INCREASED PLASMA LEVELS OF CHEMOKINES AND ADIPOKINES CHARACTERISTIC OF CHRONIC SYSTEMIC INFLAMMATION, AND DIETARY FACTORS SUCH AS FISH OILS AND PHYTOCHEMICALS HAVE BEEN SHOWN TO HAVE ANTI-INFLAMMATORY PROPERTIES AS WELL AS MODULATING ESTABLISHED RISK FACTORS SUCH AS APOPTOSIS AND CELL PROLIFERATION. THERE IS ALSO SOME EVIDENCE THAT DIET CAN MODIFY EPIGENETIC CHANGES. THIS PAPER BRIEFLY REVIEWS THE CURRENT STATE OF KNOWLEDGE IN RELATION TO CRC DEVELOPMENT AND CONSIDERS EVIDENCE FOR POTENTIAL MECHANISMS BY WHICH DIET MAY MODIFY RISK. 2011