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Published byChristian Whitehead Modified over 9 years ago
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Niko Bla ž evi ć Mentor: A. Ž mega č Horvat
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The process of transformation from a normal cell to a cancerous one Synonym: neoplasia Carcin ogenes is
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Neoplasia is an abnormality of cell growth and multiplication characterised by: At cellular level Excessive cellular proliferation Uncoordinated growth Tissue infiltration At molecular level Disorder of growth regulatory genes Carcin ogenes is
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NORMAL CELL growth factor growth factor receptor signal transduction activation of transcription cytoplasm nucleus DNA RNA Carcin ogenes is
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NEOPLASTIC (malignant) CELLS Increase in growth factors Increase in growth factor receptors Increase in signal transduction Increase in activation of transcription - Disturbed processes of mitosis and protein synthesis Carcin ogenes is
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Continuous reproduction Formation of abnormal proteins ANAPLASIA: ▪ loss of normal cell function (abnormal DNA transcription) ▪ proliferation ▪ movement of cells ▪ invasion of nearby tissue ▪ metastasis Carcin ogenes is Caused by altered DNA and altered cellular programs which make new signals
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two general types Monoclonal ▪ initial neoplastic change affects a single cell Field origin ▪ carcinogen acts on large number of cells producing field of potentially neoplastic cells Carcin ogenes is
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Proto-oncogenes ( activated oncogenes ) – code for: ▪ growth factors ▪ receptors ▪ signal-relay or transduction factors ras - colon cancer myc - lymphoma bcr-abl - chronic myelogenous leukemia (Philladelphia chromosome) Tumor suppressor genes - code for factors that down- regulate the cell cycle, promote differentiation and supress oncogenes from causing cancer Rb-1 – retinoblastoma gene p53 Carcin ogenes is
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NEOPLASIA proto-oncogene is activated or tumor suppressor gene is inactivated normal growth oncogenesis Activation of proto-oncogene: point mutation translocation gene amplification Also - Failure of Immune Surveillance theory : immune system responds to neoantigens as to foreign antigens, but neoplastic cells escape recognition and destruction --> become clinical cancers Carcin ogenes is
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Environmental agents Heredity Carcin ogenes is
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Chemical carcinogens: hydrocarbons (cigarette smoke, pipe smoke, automobile exhaust gases) insecticides dyes industrial chemicals insulation hormones E.g. - DES (diethylstilbestrol) - estrogen drugs Carcin ogenes is
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Radiation: sunlight X-rays radioactive substances nuclear fusion Energy interacts with DNA causing its damage and mutation, which leads to CANCER E.g. - leukemia (radiologists, atomic bomb survivors) - skin cancer – UV radiation from the sun Carcin ogenes is
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Viruses (oncogenic viruses) HTLV – causes a form of leukemia in adults Herpes VIII – Kaposi sarcoma Papilloma virus – cervical carcinoma Epstein-Barr virus – Burkitt lymphoma Two types – RNA and DNA viruses Carcin ogenes is
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Transmission of some forms of cancer from parents to offspring through defects in the DNA of the egg or sperm cells E.g. Retinoblastoma – tumor of the retina of the eye Polyposis coli syndrome – polyps that grow in the colon and rectum Other colon, breast and kidney cancers Cause: loss of a segment of DNA or a change in the coding sequence of DNA Detection – DNA sequencing, DNA probes In many cases – abnormalities in tumor suppressor genes Carcin ogenes is
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Genetic screening – detection of inherited cancer- causing gene by testing the blood cells of family members (inherited changes can be detected in all tissues of the body, not only cancerous cells) Carcin ogenes is
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en.wikipedia.org/wiki/Carcinogenesis 4th year handouts Google.com ... Carcin ogenes is
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