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Published byGerard Rice Modified over 9 years ago
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Normal haemopoiesis
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ABNORMALITIES IN THE HEMOPOIETIC SYSTEM CAN LEAD TO HEMOGLOBINOPATHIES HEMOPHILIA DEFECTS IN HEMOSTASIS/THROMBOSIS HEMATOLOGICAL MALIGNANCY
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MUTATIONS AND DNA VARIOUS TYPES OF MUTATIONS CAN OCCUR LEADING TO DISEASE PHENOTYPE POINT MUTATIONS INSERTIONS OR DELETIONS TRANSLOCATIONS COMPLEX CHROMOSOMAL REARRANGEMENTS
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EXAMPLE OF COMMON MUTATIONS IN HUMAN DISEASE
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Sickle cell disease
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Sickle cell disease, morphology and molecular
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VARIABILITY IN GENETIC DISEASES ONE DISEASE, ONE GENE, ONE MUTATION ONE DISEASE, ONE GENE, MANY MUTATIONS ONE DISEASE, MORE THAN ONE GENE, MANY MUTATIONS
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HAEMOPHILIA X LINKED RECESSIVE DISORDER HAEMOPHILIA A – MUTATIONS IN FACTOR VIII GENE HAEMOPHILIA B – MUTATIONS IN FACTOR IX GENE SIMPLE AND COMPLICATED MUTATIONS THE FLIP TIP MUTATION
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F8A E1 E22 E23 E26 F8A E1 E22 E23 E26 TEL CEN TEL INVERSION 22 E1E22E23 E26 A B C FIGURE 4 THE IVS 22 MUTATION IN HAEMOPHILIA A. F8B
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Genetic factors and deep vein thrombosis FACTOR V LEIDEN MUTATION PROTHROMBIN MUTATION ? OTHER FACTORS IN THE PROTEIN C PATHWAY FVL LEADS TO SIGNIFICANT INCREASE IN RISK OF DVT, PARTICULARLY IN ASSOCIATION WITH OTHER ENVIRONMENTAL FACTORS EG OCP
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CANCER DEVELOPMENT: ITS IN THE GENES
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HOW DOES A CELL BECOME TUMORIGENIC? THREE PROCESSES ARE INVOLVED IMMORTALISATION TRANSFORMATION METASTASIS
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IMMORTALISATION PROCESS BY WHICH THE CELLS ARE INDUCED TO GROW INDEFINITELY
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TRANSFORMATION CELLS ARE NOT CONSTRAINED IN TERMS OF GROWTH CHARACTERISTICS AND TEND TO BECOME FACTOR INDEPENDENT
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METASTASIS CANCER CELLS GAIN THE ABILITY TO INVADE NORMAL TISSUE AND ESTABLISH OTHER FOCI OF MALIGNANCY
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WHAT CAUSES CELL TRANSFORMATION? ENVIRONMENTAL CARCINOGENS(INITIATORS AND PROMOTERS) GENETIC SOMATIC MUTATIONS MENDELIAN INHERITANCE
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ONCOGENES NORMAL CELLULAR COUNTERPARTS(PROTO- ONCOGENES) MUTATION/ACTIVATION LEADS TO TUMOR FORMATION HUNDREDS OF ONCOGENES IDENTIFIED GAIN OF FUNCTION
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Tumour suppressor genes Originally known as recessive oncogenes Need to have both copies of the gene affected to promote a malignant phenotype Knudsons 2 hit hypothesis First mutation makes cells susceptiple to development of cancer 2 nd hit leads to a malignant phenotype
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TRANSLOCATIONS AND CANCER SEEMS PARTICULARLY RELEVANT IN HEMATOLOGICAL MALIGNANCIES CHRONIC MYELOID LEUKEMIA ACUTE PROMYELOCYTIC LEUKEMIA BURKITTS LYMPHOMA NON HODGKINS LYMPHOMA
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Leukaemia, the current hypothesis Defect in maturation of white blood cells May involve a block in differentiation and/or a block in apoptosis Acquired genetic defect Initiating events unclear Transformation events involve acquired genetic changes Chromosomal translocation implicated in many forms of leukaemia
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Chronic Myeloid Leukaemia Malignancy of the haemopoietic system Transformation of the pluripotent stem cell 9;22 translocation giving rise to the Philadelphia (Ph’) chromosome Creation of a leukaemia specific mRNA (BCR- ABL) Resistance to apoptosis, abnormal signalling and adhesion Molecular diagnostics Molecular and cellular therapeutics
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Cytogenetic Abnormality of CML: The Ph Chromosome 12345 6781011912 131415161718 19202122xY
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The Ph Chromosome: t(9;22) Translocation 22 bcr abl Ph ( or 22q-) bcr-abl FUSION PROTEIN WITH TYROSINE KINASE ACTIVITY 9 9 q+
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Prevalence of the Ph Chromosome in Haematological Malignancies Leukaemia% of Ph+ Patients CML95 ALL (Adult)15–30 ALL (Paediatric)5 AML2 Faderl S et al. Oncology (Huntingt). 1999;13:169-184.
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bcr-abl Gene and Fusion Protein Tyrosine Kinases Adapted from Melo JV. Blood. 1996;88:2375-2384. p210 Bcr-Abl p185 Bcr-Abl 2-11 Chromosome 9 c-bcr Chromosome 22 c-abl Exons Introns CML Breakpoints ALL Breakpoints 1 2-11
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NON HODGKINS LYMPHOMA B CELL FOLLICULAR LYMPHOMA t(14;18)(q21;q14) BCL 2 AND IMMUNOGLOBULIN GENES INVOLVED DYSREGULATION OF BCL 2 FAILURE OF APOPTOSIS
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Detecting Cancer – where to begin?
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Detecting cancer, the need for a marker of disease
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Detecting Cancer – different markers for different diseases?
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Cancer Molecular Diagnostics – discriminating cancers at the gene level
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How Cancer Molecular Diagnostics? Chromosome analysis Gene analysis Gene expression analysis Protein analysis Gene chip analysis
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Leukaemia diagnostics Morphology Cytogenetics Fluorescent In Situ Hybridisation (FISH) Immunophenotyping PCR of chromosomal translocations
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New developments in Cancer Molecular Diagnostics The Gene Chip
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The Gene Chip, a Molecular snap shot of the cell
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MOLECULAR MEDICINE A new approach to medicine New Diagnostics New Therapeutics A number of agents now in clinical trials Molecular medicine will help identify new targets and permit rational drug development
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