1 4148 156 MECHANISTIC BASIS OF EX VIVO UMBILICAL CORD BLOOD STEM PROGENITOR CELL EXPANSION. UMBILICAL CORD BLOOD (CB) TRANSPLANTATION HAS BEEN USED SUCCESSFULLY IN HUMANS FOR THREE DECADES DUE TO ITS RAPID AVAILABILITY FOR PATIENTS LACKING A SUITABLE ALLOGENEIC DONOR, LESS STRINGENT HLA MATCHING REQUIREMENTS, AND LOW RATES OF RELAPSE AND CHRONIC GRAFT-VERSUS-HOST DISEASE (GVHD). HOWEVER, CB TRANSPLANTATION IS ASSOCIATED WITH COMPLICATIONS, SUCH AS DELAYED HEMATOPOIETIC ENGRAFTMENT, GRAFT FAILURE, WHICH INCREASES INFECTION AND BLEEDING AND CAUSES LONGER HOSPITAL STAYS, AND TRANSPLANT-RELATED MORTALITY. THE MAJORITY OF THESE BIOLOGICAL LIMITATIONS ARE DUE TO THE UNFORESEEABLE FUNCTIONAL POTENCY OF MULTIPOTENT HEMATOPOIETIC STEM CELLS (HSCS), WHICH REDUCE THE PREDICTABILITY OF SUCCESSFUL TRANSPLANTATION; HOWEVER, SEVERAL STRATEGIES HAVE BEEN DEVELOPED TO INCREASE THE NUMBER OF HEMATOPOIETIC STEM PROGENITOR CELLS (HSPCS) INFUSED DURING CB TRANSPLANTATION. THIS REVIEW PRIMARILY ADDRESSES THE METHODS THAT PROMOTE EX VIVO CB EXPANSION WITHIN THE CONTEXT OF SYMMETRICAL AND ASYMMETRICAL HSC DIVISION AND THOSE THAT RELY ON EPIGENETIC MECHANISMS, ALONG WITH THE REPORTEDLY MOST SUCCESSFUL CYTOKINE COMBINATIONS. WE ALSO REVIEW RECENT CLINICAL RESEARCH ON SMALL MOLECULES (STEMREGENIN-1, UM171, AND NICOTINAMIDE) IN EX VIVO EXPANDED CB AND DISCUSS YET UNVALIDATED PRECLINICAL STRATEGIES. EXPANDING AND TRANSPLANTING CB GRAFT ENRICHED IN HSPCS IN A SINGLE CB UNIT IS A PARTICULARLY EXCITING PROSPECT WITH THE POTENTIAL TO IMPROVE THE USE AND AVAILABILITY OF CB GRAFTS. GREATER KNOWLEDGE OF OPTIMAL EX VIVO EXPANSION STRATEGIES, CELL LONGEVITY, AND GRAFT POTENCY WILL EXPAND THE SCOPE OF CELLULAR THERAPIES. ALSO THE DEVELOPMENT OF ADEQUATE EX VIVO HSPC EXPANSION STRATEGIES COULD BRING EXPANDED CORD BLOOD GRAFTS TO THE FOREFRONT OF TRANSPLANT THERAPY AND REGENERATIVE MEDICINE. 2020 2 5428 36 REGULATION OF STRESS-INDUCED HEMATOPOIESIS. PURPOSE OF REVIEW: THE HEMATOPOIETIC COMPARTMENT IS TASKED WITH THE ESTABLISHMENT AND MAINTENANCE OF THE ENTIRE BLOOD PROGRAM IN STEADY-STATE AND IN RESPONSE TO STRESS. KEY TO THIS PROCESS ARE HEMATOPOIETIC STEM CELLS (HSCS), WHICH POSSESS THE UNIQUE ABILITY TO SELF-RENEW AND DIFFERENTIATE TO REPLENISH BLOOD CELLS THROUGHOUT AN ORGANISM'S LIFETIME. THOUGH TIGHTLY REGULATED, THE HEMATOPOIETIC SYSTEM IS VULNERABLE TO BOTH INTRINSIC AND EXTRINSIC FACTORS THAT INFLUENCE HEMATOPOIETIC STEM AND PROGENITOR CELL (HSPC) FATE. HERE, WE REVIEW RECENT ADVANCES IN OUR UNDERSTANDING OF HEMATOPOIETIC REGULATION UNDER STRESS CONDITIONS SUCH AS INFLAMMATION, AGING, MITOCHONDRIAL DEFECTS, AND DAMAGE TO DNA OR ENDOPLASMIC RETICULUM. RECENT FINDINGS: RECENT STUDIES HAVE ILLUSTRATED THE VAST MECHANISMS INVOLVED IN REGULATING STRESS-INDUCED HEMATOPOIESIS, INCLUDING CYTOKINE-MEDIATED LINEAGE BIAS, GENE SIGNATURE CHANGES IN AGED HSCS ASSOCIATED WITH CHRONIC INFLAMMATION, THE IMPACT OF CLONAL HEMATOPOIESIS AND STRESS TOLERANCE, CHARACTERIZATION OF THE HSPC RESPONSE TO ENDOPLASMIC RETICULUM STRESS AND OF SEVERAL EPIGENETIC REGULATORS THAT INFLUENCE HSPC RESPONSE TO CELL CYCLE STRESS. SUMMARY: SEVERAL KEY RECENT FINDINGS HAVE DEEPENED OUR UNDERSTANDING OF STRESS HEMATOPOIESIS. THESE STUDIES WILL ADVANCE OUR ABILITIES TO REDUCE THE IMPACT OF STRESS IN DISEASE AND AGING THROUGH CLINICAL INTERVENTIONS TO TREAT STRESS-RELATED OUTCOMES. 2020 3 3651 34 INCREASING COMPLEXITY OF MOLECULAR LANDSCAPES IN HUMAN HEMATOPOIETIC STEM AND PROGENITOR CELLS DURING DEVELOPMENT AND AGING. THE PAST FIVE DECADES HAVE SEEN SIGNIFICANT PROGRESS IN OUR UNDERSTANDING OF HUMAN HEMATOPOIESIS. THIS HAS IN PART BEEN DUE TO THE UNPRECEDENTED DEVELOPMENT OF ADVANCED TECHNOLOGIES, WHICH HAVE ALLOWED THE IDENTIFICATION AND CHARACTERIZATION OF RARE SUBSETS OF HUMAN HEMATOPOIETIC STEM AND PROGENITOR CELLS AND THEIR LINEAGE TRAJECTORIES FROM EMBRYONIC THROUGH TO ADULT LIFE. ADDITIONALLY, SURROGATE IN VITRO AND IN VIVO MODELS, ALTHOUGH NOT FULLY RECAPITULATING HUMAN HEMATOPOIESIS, HAVE SPURRED ON THESE SCIENTIFIC ADVANCES. THESE APPROACHES HAVE HEIGHTENED OUR KNOWLEDGE OF HEMATOLOGICAL DISORDERS AND DISEASES AND HAVE LED TO THEIR IMPROVED DIAGNOSIS AND THERAPIES. HERE, WE REVIEW HUMAN HEMATOPOIESIS AT EACH END OF THE AGE SPECTRUM, DURING EMBRYONIC AND FETAL DEVELOPMENT AND ON AGING, PROVIDING EXEMPLARS OF RECENT PROGRESS IN DECIPHERING THE INCREASINGLY COMPLEX CELLULAR AND MOLECULAR HEMATOPOIETIC LANDSCAPES IN HEALTH AND DISEASE. THIS REVIEW CONCLUDES BY HIGHLIGHTING LINKS BETWEEN CHRONIC INFLAMMATION AND METABOLIC AND EPIGENETIC CHANGES ASSOCIATED WITH AGING AND IN THE DEVELOPMENT OF CLONAL HEMATOPOIESIS. 2022 4 5913 32 TARGETED THERAPY IN LEUKEMIA. RESEARCH CONDUCTED OVER THE LAST TWO DECADES HAS YIELDED A DETAILED UNDERSTANDING OF THE MOLECULAR LESIONS THAT CONTRIBUTE TO THE MALIGNANT TRANSFORMATION OF HEMATOPOIETIC STEM CELLS AND COMMITTED PROGENITORS INTO THE VARIOUS FORMS OF ACUTE AND CHRONIC LEUKEMIA. ALTHOUGH OUR UNDERSTANDING OF THE MOLECULAR PATHOLOGY OF LEUKEMIA REMAINS INCOMPLETE, THE INFORMATION GAINED TO DATE HAS HAD A PROFOUND IMPACT ON THE WAY THESE MALIGNANCIES ARE BOTH DIAGNOSED AND MONITORED DURING THERAPY. MORE RECENTLY, TARGETED THERAPIES HAVE BEEN DEVELOPED AGAINST SOME OF THE IDENTIFIED GENETIC LESIONS. THESE THERAPIES HAVE LED TO SIGNIFICANT IMPROVEMENTS IN PATIENT OUTCOMES WHILE SIMULTANEOUSLY DECREASING THERAPY-RELATED TOXICITY. WITH THE ADVENT OF GENOME-WIDE METHODS TO DEFINE THE TOTAL COMPLEMENT OF GENETIC AND EPIGENETIC LESIONS INVOLVED IN LEUKEMOGENESIS, NEW TARGETED THERAPIES CAN BE ANTICIPATED. THIS REVIEW HIGHLIGHTS SOME OF THE TARGETED THERAPIES THAT ARE PRESENTLY BEING USED TO TREAT HEMATOPOIETIC MALIGNANCIES AND DESCRIBES SOME OF THE RECENT ADVANCES THAT SHOULD HAVE A SIGNIFICANT IMPACT ON THE DEVELOPMENT OF FUTURE TARGET THERAPIES. 2008 5 5523 32 RISKS AND MECHANISMS OF ONCOLOGICAL DISEASE FOLLOWING STEM CELL TRANSPLANTATION. UNIQUE BIOLOGICAL PROPERTIES OF STEM CELLS MAKE THEM A PRECIOUS SOURCE OF CELL MATERIAL FOR TREATMENT OF A NUMBER OF PATHOLOGICAL CONDITIONS. AMONG ISSUES INHIBITING TRANSITION OF STEM CELL TECHNOLOGIES TO THE CLINICS, THE RISK OF ONCOLOGICAL COMPLICATIONS OF STEM CELL-BASED THERAPIES IS THE MOST CRITICAL. A MASSIVE AMOUNT OF CLINICAL AND EXPERIMENTAL DATA DEMONSTRATES THAT BOTH HEMATOLOGICAL (INCLUDING ACUTE AND CHRONIC MYELOID LEUKEMIA) AND NON-HEMATOLOGICAL (INCLUDING TERATOMA AND NON-TERATOMA TUMORS) MALIGNANCIES COULD ARISE FROM DONOR STEM CELLS OF DIFFERENT TYPES. A WIDE SPECTRUM OF MECHANISMS COULD UNDERLIE THE DEVELOPMENT OF ONCOLOGICAL DISEASE IN RECIPIENTS, INCLUDING: I) BLAST TRANSFORMATION OF PROLIFERATING DONOR STEM CELLS UNDER PERSISTENT ACTION OF CERTAIN FACTORS IN THE RECIPIENT, THUS CAUSING DE NOVO MALIGNANCIES; II) CONTAMINATION OF DONOR CELL MATERIAL WITH MALIGNANT CELLS; III) TRANSMISSION OF PARTICULAR VIRAL SUBTYPES WITH DONOR STEM CELLS, COMBINED WITH IMMUNOSUPPRESSION THERAPY EFFECTS; IV) UNCONTROLLABLE PROLIFERATION OF RESIDUAL UNDIFFERENTIATED STEM CELLS OF VARIOUS PLASTICITY; AND V) KARYOTYPIC INSTABILITY IN STEM CELLS FOLLOWING PROLONGED CULTURING/EXPANSION IN VITRO. POTENTIAL PREVENTIVE STRATEGIES ARE DIVERSE AND INCLUDE I) HIGH-THROUGHPUT CELL SORTING-BASED STRATEGIES; II) INTRODUCTION OF SUICIDE GENES INTO THE DONOR STEM CELL GENOME; III) APPLICATION OF APOPTOSIS-INDUCING EPIGENETIC FACTORS; AND SOME OTHER OPTIONS. 2010 6 6449 49 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 7 3996 36 LOOKING FORWARD: NOVEL THERAPEUTIC APPROACHES IN CHRONIC AND ADVANCED PHASES OF MYELOFIBROSIS. MYELOFIBROSIS (MF) IS COMPLEX AT THE PATHOBIOLOGIC LEVEL AND HETEROGENEOUS AT THE CLINICAL LEVEL. THE ADVANCES IN MOLECULAR CHARACTERIZATION OF MF PROVIDE IMPORTANT INSIGHT INTO THE MECHANISMS DRIVING THIS CHRONIC MYELOID MALIGNANCY, REFINE RISK STRATIFICATION, OFFER NOVEL THERAPEUTIC TARGETS, AND SERVE TO MEASURE THERAPEUTIC RESPONSE. ALTHOUGH JAK2 INHIBITION HAS BEEN THE FOCUS OF LABORATORY AND CLINICAL EFFORTS OVER THE LAST DECADE, CURRENT EXPERIMENTAL THERAPEUTIC APPROACHES HAVE BROADENED TO INCLUDE INHIBITORS OF KEY ALTERNATIVE SIGNALING PATHWAYS, EPIGENETIC MODULATORS, ANTI-FIBROTICS, AND IMMUNOTHERAPIES. BASED ON COMPELLING PRECLINICAL RATIONALE, A NUMBER OF JAK2 INHIBITOR BASED COMBINATION THERAPIES ARE NOW ACTIVELY BEING EVALUATED IN THE CLINIC WITH THE GOAL OF DISEASE COURSE MODIFICATION. THE ROLE AND TIMING OF HEMATOPOIETIC STEM CELL TRANSPLANT (HSCT) FOR MF HAS BEEN CHALLENGED WITH THE AVAILABILITY OF COMMERCIAL RUXOLITINIB AND THE PLETHORA OF EXPERIMENTAL TREATMENT OPTIONS THAT EXIST. INTEGRATION OF PRECONDITIONING JAK2 INHIBITION, REDUCED INTENSITY CONDITIONING REGIMENS, AND ALTERNATIVE DONOR SOURCES ARE ALL BEING EXPLORED IN AN ATTEMPT TO OPTIMIZE THIS POTENTIALLY CURATIVE MODALITY. THIS REVIEW WILL SUMMARIZE MODERN MF RISK STRATIFICATION, CURRENT CLINICAL RESEARCH APPROACHES TO CHRONIC AND ADVANCE PHASE MF FOCUSING ON NOVEL AGENTS ALONE AND IN COMBINATION, AND UPDATE THE READER ON NEW DIRECTIONS IN HSCT. 2015 8 1882 32 EMERGING TREATMENTS IN ACUTE MYELOID LEUKAEMIA. ACUTE MYELOID LEUKAEMIA (AML) IS THE MOST COMMON FORM OF LEUKAEMIA IN YOUNG ADULTS. ALTHOUGH 75-85% OF PATIENTS WILL ACHIEVE COMPLETE REMISSION AFTER INDUCTION CHEMOTHERAPY, THE LONG-TERM SURVIVAL IS STILL < 50% AT 5 YEARS. CHEMOTHERAPY HAS INCREASED IN INTENSITY IN RECENT YEARS AND IS PERCEIVED TO HAVE REACHED THE LIMIT OF TOXICITY. ALLOGENEIC BONE MARROW TRANSPLANTATION, WHICH IS UNDOUBTEDLY THE MOST EFFECTIVE WAY TO PREVENT RELAPSE, MAY NOT ADD SUBSTANTIAL SURVIVAL BENEFITS. SEVERAL NEW PHARMACOLOGICAL APPROACHES TO THE TREATMENT OF AML ARE NOW BECOMING AVAILABLE, WITH VARIOUS MOLECULAR TARGETS IDENTIFIED, INCLUDING THE FARNESYLATION OF RAS FAMILY PROTEINS AND TYROSINE KINASES INVOLVED IN SIGNAL TRANSDUCTION AND EPIGENETIC METHYLATION. MORE SELECTIVE DELIVERY OF CHEMOTHERAPEUTIC AGENTS IS ALSO FEASIBLE USING HUMANISED MONOCLONAL ANTIBODIES, WITH THE INTRIGUING POSSIBILITY OF INCREASING TREATMENT DELIVERY WITHOUT INCREASING THE TOXICITY. HOWEVER, DESPITE THE PROGRESS IN THE RATIONAL DESIGN OF DRUGS IN DISORDERS SUCH AS CHRONIC MYELOID LEUKAEMIA, AML LACKS A SINGLE SPECIFIC PATHOGNOMIC GENETIC EVENT TO ACT AS A DRUG TARGET. THIS REVIEW DISCUSSES THE DRUGS PRESENTLY UNDER INVESTIGATION IN PHASE II OR PHASE III TRIALS IN AML. 2004 9 4918 35 PANCREATIC CANCER: FROM BENCH TO 5-YEAR SURVIVAL. PANCREATIC DUCTAL ADENOCARCINOMA IS ONE OF THE MOST AGGRESSIVE HUMAN MALIGNANCIES, WITH AN OVERALL 5-YEAR SURVIVAL RATE OF LESS THAN 4%. ON THE MOLECULAR LEVEL, AN INCREASING NUMBER OF GENETIC AND EPIGENETIC ALTERATIONS HAVE BEEN DISCOVERED, WITH A PARTICULAR FOCUS ON GROWTH FACTORS AND RELATED PATHWAYS. SMALL-MOLECULE TYROSINE KINASE INHIBITORS, ANTIBODIES, AND OTHER APPROACHES HAVE BEEN DEVELOPED IN RECENT YEARS TO TARGET THESE SIGNAL TRANSDUCTION PATHWAYS, AND FIRST CLINICAL TRIALS SHOW ENCOURAGING RESULTS. IN ADDITION, MOLECULAR ALTERATIONS HAVE BEEN IDENTIFIED THAT ENABLE THE CANCER CELLS TO INVADE THE PERINEURIUM AND THE RETROPERITONEAL SPACE, THUS EXPLAINING AT LEAST IN PART THE HIGH RATE OF LOCAL RECURRENCE AND THE SEVERE PAIN SYNDROME. TECHNICALLY, PANCREATIC SURGERY HAS ADVANCED, WITH ACCEPTABLE MORBIDITY AND MORTALITY RATES IN HIGH-VOLUME CENTERS. RANDOMIZED CONTROLLED TRIALS ARE INCREASINGLY CARRIED OUT TO DEFINE THE BEST PALLIATIVE AND ADJUVANT THERAPY FOR THIS DISEASE. TRANSLATIONAL RESEARCH COMBINED WITH CLINICAL TRIALS WILL HOPEFULLY LEAD TO IMPROVED SURVIVAL AND BETTER QUALITY OF LIFE FOR PANCREATIC CANCER PATIENTS IN THE FUTURE. 2006 10 737 37 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 11 943 25 CHRONIC LYMPHOCYTIC LEUKEMIA. PATIENTS WITH CHRONIC LYMPHOCYTIC LEUKEMIA CAN BE DIVIDED INTO THREE CATEGORIES: THOSE WHO ARE MINIMALLY AFFECTED BY THE PROBLEM, OFTEN NEVER REQUIRING THERAPY; THOSE THAT INITIALLY FOLLOW AN INDOLENT COURSE BUT SUBSEQUENTLY PROGRESS AND REQUIRE THERAPY; AND THOSE THAT FROM THE POINT OF DIAGNOSIS EXHIBIT AN AGGRESSIVE DISEASE NECESSITATING TREATMENT. LIKEWISE, SUCH PATIENTS PASS THROUGH THREE PHASES: DEVELOPMENT OF THE DISEASE, DIAGNOSIS, AND NEED FOR THERAPY. FINALLY, THE LEUKEMIC CLONES OF ALL PATIENTS APPEAR TO REQUIRE CONTINUOUS INPUT FROM THE EXTERIOR, MOST OFTEN THROUGH MEMBRANE RECEPTORS, TO ALLOW THEM TO SURVIVE AND GROW. THIS REVIEW IS PRESENTED ACCORDING TO THE TEMPORAL COURSE THAT THE DISEASE FOLLOWS, FOCUSING ON THOSE EXTERNAL INFLUENCES FROM THE TISSUE MICROENVIRONMENT (TME) THAT SUPPORT THE TIME LINES AS WELL AS THOSE INTERNAL INFLUENCES THAT ARE INHERITED OR DEVELOP AS GENETIC AND EPIGENETIC CHANGES OCCURRING OVER THE TIME LINE. REGARDING THE FORMER, SPECIAL EMPHASIS IS PLACED ON THE INPUT PROVIDED VIA THE B-CELL RECEPTOR FOR ANTIGEN AND THE C-X-C-MOTIF CHEMOKINE RECEPTOR-4 AND THE THERAPEUTIC AGENTS THAT BLOCK THESE INPUTS. REGARDING THE LATTER, PROMINENCE IS LAID UPON INHERITED SUSCEPTIBILITY GENES AND THE GENETIC AND EPIGENETIC ABNORMALITIES THAT LEAD TO THE DEVELOPMENTAL AND PROGRESSION OF THE DISEASE. 2021 12 736 37 CANCER STEM CELLS--NEW APPROACH TO CANCEROGENENSIS AND TREATMENT. RECENTLY, THERE IS AN INCREASING EVIDENCE SUPPORTING THE THEORY OF CANCER STEM CELLS NOT ONLY IN LEUKEMIA BUT ALSO IN SOLID CANCER. 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. THIS REVIEW IS FOCUSING ON THE RECENT DISCOVERY OF STEM CELLS IN LEUKEMIA, HUMAN BRAIN TUMORS AND BREAST CANCER. A SMALL POPULATION OF CELLS IN THE TUMOR (LESS THAN 1%) SHOWS THE POTENTIAL TO GIVE RISE TO THE TUMOR AND ITS GROWTH. THESE CELLS HAVE A SUBSTANTIAL CHARACTERISTIC OF STEM CELLS--ABILITY FOR SELF-RENEWAL WITHOUT LOSS OF PROLIFERATION CAPACITY WITH EACH CELL DIVISION. FURTHERMORE THEY ARE IMMORTAL, RATHER RESISTANT TO TREATMENT AND EXPRESS TYPICAL MARKERS OF STEM CELLS. THE ORIGIN OF THESE RESIDENT CANCER STEM CELLS IS NOT CLEAR. WHETHER THE CANCER STEM CELLS ORIGINATE FROM NORMAL STEM CELLS IN CONSEQUENCE OF GENETIC AND EPIGENETIC CHANGES AND/OR REDIFFERENTIATION FROM SOMATIC TUMOR CELLS TO THE STEM-LIKE CELLS REMAINS TO BE INVESTIGATED. WE PROPOSE THE IDEA OF THE RELATION BETWEEN NORMAL TISSUE STEM CELLS AND CANCER STEM CELLS AND THEIR POPULATIONS--PROGENITOR CELLS. BASED ON THIS WE HIGHLIGHT ONE OF THE MAJOR CHARACTERISTIC OF STEM CELL--PLASTICITY, WHICH IS EQUALLY IMPORTANT IN THE PHYSIOLOGICAL REGENERATION PROCESS AS WELL AS CARCINOGENESIS. FURTHERMORE, WE CONSIDER THE MICROENVIRONMENT AS A LIMITING FACTOR FOR TUMOR GENESIS IN AML, BREAST CANCER AND BRAIN TUMORS. THUS THE BIOLOGICAL PROPERTIES OF CANCER STEM CELLS ARE JUST BEGINNING TO BE REVEALED, THE CONTINUATION OF THESE STUDIES SHOULD LEAD TO THE DEVELOPMENT OF CANCER STEM CELLS TARGET THERAPIES FOR CANCER TREATMENT. 2008 13 3565 36 IMPACT OF GENETIC POLYMORPHISMS AND BIOMARKERS ON THE EFFECTIVENESS AND TOXICITY OF TREATMENT OF CHRONIC MYELOID LEUKEMIA AND ACUTE MYELOID LEUKEMIA. MOST MALIGNANT HEMATOLOGICAL DISEASES ARE GENERALLY A CONSEQUENCE OF ACQUIRED MUTATIONS OR REARRANGEMENTS IN CELL REPLICATION PROCESSES. ACUTE MYELOID LEUKEMIA (AML) IS A CLINICALLY AND MOLECULARLY HETEROGENEOUS DISEASE THAT RESULTS FROM ACQUIRED GENETIC AND EPIGENETIC ALTERATIONS IN HEMATOPOIETIC PROGENITOR CELLS. DESPITE THE ADVANCES MADE IN UNDERSTANDING THE PATHOGENESIS OF THIS DISEASE, THE OVERALL SURVIVAL OF PATIENTS REMAINS VERY LOW DUE TO THE HIGH RELAPSE RATE. PHARMACOGENETICS AND MASSIVE SEQUENCING STUDIES HAVE ALLOWED THE IDENTIFICATION OF NEW RECURRENT MUTATIONS WITH SIGNIFICANT PROGNOSTIC IMPACT IN AML; FURTHERMORE, IT SEEMS LIKELY THAT WHOLE GENOME SEQUENCING WILL SOON BECOME A STANDARD DIAGNOSTIC TEST, WHICH WILL ALLOW THE MOLECULAR DIAGNOSIS OF PATIENTS. THEREFORE, IT IS NECESSARY TO DEVELOP MOLECULAR TARGETS THAT OPEN NEW THERAPEUTIC PERSPECTIVES AND ALLOW INDIVIDUALIZED TREATMENT OF PATIENTS WITH THIS AGGRESSIVE DISEASE. CHRONIC MYELOID LEUKEMIA (CML) IS THE FIRST NEOPLASTIC DISEASE FOR WHICH A CHARACTERISTIC GENETIC ALTERATION WAS DESCRIBED. IT HAS, BY DEFINITION, A GENETIC MARKER, THE BCR::ABL1 REARRANGEMENT, AS A CONSEQUENCE OF THE T9;22(Q34;Q11) TRANSLOCATION. ITS STUDY IS ESSENTIAL FOR THE DIAGNOSIS OF THIS ENTITY AND ALSO FOR MONITORING THE RESPONSE TO TREATMENT. DRUGS KNOWN AS TYROSINE KINASE INHIBITORS (TKIS) THAT TARGET THE BCR::ABL1 PROTEIN (ORAL TARGETED THERAPY) ARE THE CONVENTIONAL TREATMENT OF CML, REPRESENTING A CHANGE OF PARADIGM IN THE MANAGEMENT OF ONCOHEMATOLOGICAL PATIENTS. 2022 14 6013 42 THE APPLICATIONS OF DNA METHYLATION AS A BIOMARKER IN KIDNEY TRANSPLANTATION: A SYSTEMATIC REVIEW. BACKGROUND: ALTHOUGH KIDNEY TRANSPLANTATION IMPROVES PATIENT SURVIVAL AND QUALITY OF LIFE, LONG-TERM RESULTS ARE HAMPERED BY BOTH IMMUNE- AND NON-IMMUNE-MEDIATED COMPLICATIONS. CURRENT BIOMARKERS OF POST-TRANSPLANT COMPLICATIONS, SUCH AS ALLOGRAFT REJECTION, CHRONIC RENAL ALLOGRAFT DYSFUNCTION, AND CUTANEOUS SQUAMOUS CELL CARCINOMA, HAVE A SUBOPTIMAL PREDICTIVE VALUE. DNA METHYLATION IS AN EPIGENETIC MODIFICATION THAT DIRECTLY AFFECTS GENE EXPRESSION AND PLAYS AN IMPORTANT ROLE IN PROCESSES SUCH AS ISCHEMIA/REPERFUSION INJURY, FIBROSIS, AND ALLOREACTIVE IMMUNE RESPONSE. NOVEL TECHNIQUES CAN QUICKLY ASSESS THE DNA METHYLATION STATUS OF MULTIPLE LOCI IN DIFFERENT CELL TYPES, ALLOWING A DEEP AND INTERESTING STUDY OF CELLS' ACTIVITY AND FUNCTION. THEREFORE, DNA METHYLATION HAS THE POTENTIAL TO BECOME AN IMPORTANT BIOMARKER FOR PREDICTION AND MONITORING IN KIDNEY TRANSPLANTATION. PURPOSE OF THE STUDY: THE AIM OF THIS STUDY WAS TO EVALUATE THE ROLE OF DNA METHYLATION AS A POTENTIAL BIOMARKER OF GRAFT SURVIVAL AND COMPLICATIONS DEVELOPMENT IN KIDNEY TRANSPLANTATION. MATERIAL AND METHODS: A SYSTEMATIC REVIEW OF SEVERAL DATABASES HAS BEEN CONDUCTED. THE NEWCASTLE-OTTAWA SCALE AND THE JADAD SCALE HAVE BEEN USED TO ASSESS THE RISK OF BIAS FOR OBSERVATIONAL AND RANDOMIZED STUDIES, RESPECTIVELY. RESULTS: TWENTY ARTICLES REPORTING ON DNA METHYLATION AS A BIOMARKER FOR KIDNEY TRANSPLANTATION WERE INCLUDED, ALL USING DNA METHYLATION FOR PREDICTION AND MONITORING. DNA METHYLATION PATTERN ALTERATIONS IN CELLS ISOLATED FROM DIFFERENT TISSUES, SUCH AS KIDNEY BIOPSIES, URINE, AND BLOOD, HAVE BEEN ASSOCIATED WITH ISCHEMIA-REPERFUSION INJURY AND CHRONIC RENAL ALLOGRAFT DYSFUNCTION. THESE ALTERATIONS OCCURRED IN DIFFERENT AND SPECIFIC LOCI. DNA METHYLATION STATUS HAS ALSO PROVED TO BE IMPORTANT FOR IMMUNE RESPONSE MODULATION, HAVING A CRUCIAL ROLE IN REGULATORY T CELL DEFINITION AND ACTIVITY. RESEARCH ALSO FOCUSED ON A BETTER UNDERSTANDING OF THE ROLE OF THIS EPIGENETIC MODIFICATION ASSESSMENT FOR REGULATORY T CELLS ISOLATION AND EXPANSION FOR FUTURE TOLERANCE INDUCTION-ORIENTED THERAPIES. CONCLUSIONS: STUDIES INCLUDED IN THIS REVIEW ARE HETEROGENEOUS IN STUDY DESIGN, BIOLOGICAL SAMPLES, AND OUTCOME. MORE COORDINATED INVESTIGATIONS ARE NEEDED TO AFFIRM DNA METHYLATION AS A CLINICALLY RELEVANT BIOMARKER IMPORTANT FOR PREVENTION, MONITORING, AND INTERVENTION. 2022 15 6320 46 THE ROCKY ROAD TO PERSONALIZED MEDICINE IN ACUTE MYELOID LEUKAEMIA. ACUTE MYELOID LEUKAEMIA (AML) IS A MALIGNANT DISORDER OF THE MYELOID BLOOD LINEAGE CHARACTERIZED BY IMPAIRED DIFFERENTIATION AND INCREASED PROLIFERATION OF HEMATOPOIETIC PRECURSOR CELLS. RECENT TECHNOLOGICAL ADVANCES HAVE LED TO AN IMPROVED UNDERSTANDING OF AML BIOLOGY BUT ALSO UNCOVERED THE ENORMOUS CYTOGENETIC AND MOLECULAR HETEROGENEITY OF THE DISEASE. DESPITE THIS HETEROGENEITY, AML IS MOSTLY MANAGED BY A 'ONE-SIZE-FITS-ALL' APPROACH CONSISTING OF INTENSIVE, HIGHLY TOXIC INDUCTION AND CONSOLIDATION CHEMOTHERAPY. THESE TREATMENT PROTOCOLS HAVE REMAINED LARGELY UNCHANGED FOR THE PAST SEVERAL DECADES AND ONLY LEAD TO A CURE IN APPROXIMATELY 30-35% OF CASES. THE ADVENT OF TARGETED THERAPIES IN CHRONIC MYELOID LEUKAEMIA AND OTHER MALIGNANCIES HAS SPARKED HOPE TO IMPROVE PATIENT OUTCOME IN AML. HOWEVER, THE IMPLEMENTATION OF TARGETED AGENTS IN AML THERAPY HAS BEEN UNEXPECTEDLY CUMBERSOME AND REMAINS A DIFFICULT TASK DUE TO A VARIETY OF DISEASE- AND PATIENT-SPECIFIC FACTORS. IN THIS REVIEW, WE DESCRIBE CURRENT STANDARD AND INVESTIGATIONAL THERAPEUTIC STRATEGIES WITH A FOCUS ON TARGETED AGENTS AND HIGHLIGHT POTENTIAL TOOLS THAT MIGHT FACILITATE THE DEVELOPMENT OF TARGETED THERAPIES FOR THIS FATAL DISEASE. THE CLASSES OF AGENTS DESCRIBED IN THIS REVIEW INCLUDE CONSTITUTIVELY ACTIVATED SIGNALLING PATHWAY INHIBITORS, SURFACE RECEPTOR TARGETS, EPIGENETIC MODIFIERS, DRUGS TARGETING THE INTERACTION OF THE HEMATOPOIETIC PROGENITOR CELL WITH THE STROMA AND DRUGS THAT TARGET THE APOPTOTIC MACHINERY. THE CLINICAL CONTEXT AND OUTCOME WITH THESE AGENTS WILL BE EXAMINED TO GAIN INSIGHT ABOUT THEIR OPTIMAL UTILIZATION. 2018 16 4429 44 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 3089 28 GENOMIC AND EPIGENOMIC ALTERATIONS IN CHRONIC LYMPHOCYTIC LEUKEMIA. CHRONIC LYMPHOCYTIC LEUKEMIA IS A COMMON DISEASE IN WESTERN COUNTRIES AND HAS HETEROGENEOUS CLINICAL BEHAVIOR. THE RELEVANCE OF THE GENETIC BASIS OF THE DISEASE HAS COME TO THE FOREFRONT RECENTLY, WITH GENOME-WIDE STUDIES THAT HAVE PROVIDED A COMPREHENSIVE VIEW OF STRUCTURAL VARIANTS, SOMATIC MUTATIONS, AND DIFFERENT LAYERS OF EPIGENETIC CHANGES. THE MUTATIONAL LANDSCAPE IS CHARACTERIZED BY RELATIVELY COMMON COPY NUMBER ALTERATIONS, A FEW MUTATED GENES OCCURRING IN 10-15% OF CASES, AND A LARGE NUMBER OF GENES MUTATED IN A SMALL NUMBER OF CASES. THE EPIGENOMIC PROFILE HAS REVEALED A MARKED REPROGRAMMING OF REGULATORY REGIONS IN TUMOR CELLS COMPARED WITH NORMAL B CELLS. ALL OF THESE ALTERATIONS ARE DIFFERENTIALLY DISTRIBUTED IN CLINICAL AND BIOLOGICAL SUBSETS OF THE DISEASE, INDICATING THAT THEY MAY UNDERLIE THE HETEROGENEOUS EVOLUTION OF THE DISEASE. THESE GLOBAL STUDIES ARE REVEALING THE MOLECULAR COMPLEXITY OF CHRONIC LYMPHOCYTIC LEUKEMIA AND PROVIDE NEW PERSPECTIVES THAT HAVE HELPED TO UNDERSTAND ITS PATHOGENIC MECHANISMS AND IMPROVE THE CLINICAL MANAGEMENT OF PATIENTS. 2020 18 6573 38 TREATMENT OF ACUTE MYELOID LEUKEMIA IN THE ERA OF GENOMICS-ACHIEVEMENTS AND PERSISTING CHALLENGES. ACUTE MYELOID LEUKEMIA (AML) REPRESENTS A MALIGNANT DISORDER OF THE HEMATOPOIETIC SYSTEM THAT IS MAINLY CHARACTERIZED BY RAPID PROLIFERATION, DYSREGULATED APOPTOSIS, AND IMPAIRED DIFFERENTIATION OF LEUKEMIC BLASTS. FOR SEVERAL DECADES, THE DIAGNOSTIC APPROACH IN AML WAS LARGELY BASED ON HISTOLOGIC CHARACTERISTICS WITH LITTLE IMPACT ON THE TREATMENT DECISION-MAKING PROCESS. THIS PERSPECTIVE HAS DRASTICALLY CHANGED WITHIN THE PAST YEARS DUE TO THE ADVENT OF NOVEL MOLECULAR TECHNOLOGIES, SUCH AS WHOLE GENOME NEXT-GENERATION SEQUENCING (NGS), AND THE RESULTING KNOWLEDGE GAIN IN AML BIOLOGY AND PATHOGENESIS. AFTER MORE THAN FOUR DECADES OF INTENSIVE CHEMOTHERAPY AS A "ONE-SIZE-FITS-ALL" CONCEPT, SEVERAL TARGETED AGENTS HAVE RECENTLY BEEN APPROVED FOR THE TREATMENT OF AML, EITHER AS SINGLE AGENTS OR AS PART OF COMBINED TREATMENT REGIMENS. SEVERAL OTHER COMPOUNDS, DIRECTED AGAINST REGULATORS OF APOPTOTIC, EPIGENETIC, OR MICROENVIRONMENTAL PATHWAYS, AS WELL AS MODULATORS OF THE IMMUNE SYSTEM, ARE CURRENTLY IN DEVELOPMENT AND BEING INVESTIGATED IN CLINICAL TRIALS. THE CONSTANT PROGRESS IN AML RESEARCH HAS STARTED TO PRODUCE IMPROVED SURVIVAL RATES AND FUELED HOPES THAT A ONCE RAPIDLY FATAL DISEASE CAN BE TRANSFORMED INTO A CHRONIC CONDITION. IN THIS REVIEW, THE AUTHORS PROVIDE A SUMMARY OF RECENT ADVANCES IN THE DEVELOPMENT OF TARGETED AML THERAPIES AND DISCUSS PERSISTENT CHALLENGES. 2020 19 4487 33 MOLECULARLY TARGETED DRUG COMBINATIONS DEMONSTRATE SELECTIVE EFFECTIVENESS FOR MYELOID- AND LYMPHOID-DERIVED HEMATOLOGIC MALIGNANCIES. TRANSLATING THE GENETIC AND EPIGENETIC HETEROGENEITY UNDERLYING HUMAN CANCERS INTO THERAPEUTIC STRATEGIES IS AN ONGOING CHALLENGE. LARGE-SCALE SEQUENCING EFFORTS HAVE UNCOVERED A SPECTRUM OF MUTATIONS IN MANY HEMATOLOGIC MALIGNANCIES, INCLUDING ACUTE MYELOID LEUKEMIA (AML), SUGGESTING THAT COMBINATIONS OF AGENTS WILL BE REQUIRED TO TREAT THESE DISEASES EFFECTIVELY. COMBINATORIAL APPROACHES WILL ALSO BE CRITICAL FOR COMBATING THE EMERGENCE OF GENETICALLY HETEROGENEOUS SUBCLONES, RESCUE SIGNALS IN THE MICROENVIRONMENT, AND TUMOR-INTRINSIC FEEDBACK PATHWAYS THAT ALL CONTRIBUTE TO DISEASE RELAPSE. TO IDENTIFY NOVEL AND EFFECTIVE DRUG COMBINATIONS, WE PERFORMED EX VIVO SENSITIVITY PROFILING OF 122 PRIMARY PATIENT SAMPLES FROM A VARIETY OF HEMATOLOGIC MALIGNANCIES AGAINST A PANEL OF 48 DRUG COMBINATIONS. THE COMBINATIONS WERE DESIGNED AS DRUG PAIRS THAT TARGET NONOVERLAPPING BIOLOGICAL PATHWAYS AND COMPRISE DRUGS FROM DIFFERENT CLASSES, PREFERABLY WITH FOOD AND DRUG ADMINISTRATION APPROVAL. A COMBINATION RATIO (CR) WAS DERIVED FOR EACH DRUG PAIR, AND CRS WERE EVALUATED WITH RESPECT TO DIAGNOSTIC CATEGORIES AS WELL AS AGAINST GENETIC, CYTOGENETIC, AND CELLULAR PHENOTYPES OF SPECIMENS FROM THE TWO LARGEST DISEASE CATEGORIES: AML AND CHRONIC LYMPHOCYTIC LEUKEMIA (CLL). NEARLY ALL TESTED COMBINATIONS INVOLVING A BCL2 INHIBITOR SHOWED ADDITIONAL BENEFIT IN PATIENTS WITH MYELOID MALIGNANCIES, WHEREAS SELECT COMBINATIONS INVOLVING PI3K, CSF1R, OR BROMODOMAIN INHIBITORS SHOWED PREFERENTIAL BENEFIT IN LYMPHOID MALIGNANCIES. EXPANDED ANALYSES OF PATIENTS WITH AML AND CLL REVEALED SPECIFIC PATTERNS OF EX VIVO DRUG COMBINATION EFFICACY THAT WERE ASSOCIATED WITH SELECT GENETIC, CYTOGENETIC, AND PHENOTYPIC DISEASE SUBSETS, WARRANTING FURTHER EVALUATION. THESE FINDINGS HIGHLIGHT THE HEURISTIC VALUE OF AN INTEGRATED FUNCTIONAL GENOMIC APPROACH TO THE IDENTIFICATION OF NOVEL TREATMENT STRATEGIES FOR HEMATOLOGIC MALIGNANCIES. 2017 20 4660 36 NEW APPROACHES TO THE TREATMENT OF MYELODYSPLASIA. THE THERAPEUTIC DILEMMA THAT CONFRONTS THE MANAGEMENT OF PATIENTS WITH MYELODYSPLASTIC SYNDROMES (MDS) IS ILLUSTRATED BY THE ABSENCE OF A FOOD AND DRUG ADMINISTRATION-APPROVED AGENT WITH AN INDICATION FOR THIS DISEASE. CLINICAL HETEROGENEITY AND INADEQUATE UNDERSTANDING OF THE DISEASE PATHOBIOLOGY HAVE LIMITED PROGRESS IN THE DEVELOPMENT OF NOVEL THERAPEUTICS. PRECLINICAL INVESTIGATIONS INDICATE THAT RECIPROCAL INTERACTION BETWEEN THE MALIGNANT CLONE AND THE MICROENVIRONMENT SERVE TO CREATE A HOSTILE MILIEU THAT REINFORCES INEFFECTIVE BLOOD CELL PRODUCTION. INEFFECTIVE HEMATOPOIESIS, THE HALLMARK OF MDS, ARISES FROM IMPAIRED PROGENITOR RESPONSIVENESS TO NORMAL TROPHIC SIGNALS AND EXCESS LOCAL GENERATION OF INHIBITORY CYTOKINES, WHICH PROMOTE ACCELERATED APOPTOTIC LOSS OF PROGENITORS AND THEIR PROGENY. EVIDENCE TO SUPPORT THIS MODEL DERIVES FROM CYTOKINE NEUTRALIZATION STUDIES AND THE DIRECT RELATIONSHIP BETWEEN PLASMA TUMOR NECROSIS FACTOR-ALPHA CONCENTRATION AND DNA OXIDATION AND GLUTATHIONE DEPLETION IN MALIGNANT CD34+ PROGENITORS. RECENT INVESTIGATIONS INDICATE THAT ANGIOGENIC MOLECULES GENERATED BY MALIGNANT MYELOMONOCYTIC PRECURSORS REPRESENT INTEGRAL DIFFUSABLE SIGNALS THAT REINFORCE LEUKEMIA PROGENITOR SELF-RENEWAL WHILE PROMOTING THE GENERATION OF PROAPOPTOTIC CYTOKINES AND MEDULLARY ANGIOGENIC RESPONSE. THE POTENTIAL FOR LEUKEMIA EVOLUTION IS COMPOUNDED BY EPIGENETIC EVENTS INCLUDING METHYLATION SILENCING OF THE P15 PROTO-ONCOGENE OR ACTIVATING RAS POINT MUTATIONS. DELINEATION OF SUCH BIOLOGIC FEATURES THAT ARE CENTRAL TO THE PATHOBIOLOGY OF MDS PROVIDES A RELIABLE FRAMEWORK FOR THE DEVELOPMENT OF NOVEL THERAPEUTICS. ANTIANGIOGENIC AGENTS IN CLINICAL TESTING INCLUDE VASCULAR ENDOTHELIAL GROWTH FACTOR (VEGF) RECEPTOR TYROSINE KINASE INHIBITORS, THALIDOMIDE AND RELATED ANALOGUES, AND THE RECOMBINANT VEGF NEUTRALIZING ANTIBODY, BEVACIZUMAB. AGENTS WHOSE ACTIONS MAY RESTORE DIFFERENTIATION PROGRAMS, SUCH AS THE DNA METHYLTRANSFERASE INHIBITORS OR HISTONE DEACETYLASE INHIBITORS, OFFER THE PROSPECT TO PROMOTE EFFECTIVE HEMATOPOIESIS WHILE IMPACTING THE POTENTIAL FOR LEUKEMIA EVOLUTION. RAS FARNESYL TRANSFERASE INHIBITORS HAVE SHOWN ENCOURAGING PRELIMINARY RESULTS IN ACUTE MYELOID LEUKEMIA AND ARE CURRENTLY UNDER INVESTIGATION IN ADVANCED MDS AND CHRONIC MYELOMONOCYTIC LEUKEMIA. ARSENIC TRIOXIDE (ATO) INTERACTS WITH A SPECTRUM OF BIOLOGIC TARGETS THAT MAY BE UNIQUELY SUITED TO MDS. ATO IS A POTENT INDUCER OF APOPTOSIS IN THIOL-DEPLETED MALIGNANT PROGENITORS AND NEOVASCULAR ENDOTHELIUM, WHILE PROMOTING DIFFERENTIATION THROUGH HISTONE ACETYLATION AND INACTIVATION OF TRANSCRIPTIONAL COREPRESSORS. THE IDENTIFICATION OF RELEVANT BIOLOGIC TARGETS IN MDS HAS RAISED EXPECTATIONS FOR THE DEVELOPMENT OF DISEASE-SPECIFIC THERAPIES FOR MDS IN THE YEARS THAT FOLLOW. 2002