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Niko Bla ž evi ć Mentor: A. Ž mega č Horvat.  The process of transformation from a normal cell to a cancerous one  Synonym: neoplasia Carcin ogenes.

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Presentation on theme: "Niko Bla ž evi ć Mentor: A. Ž mega č Horvat.  The process of transformation from a normal cell to a cancerous one  Synonym: neoplasia Carcin ogenes."— Presentation transcript:

1 Niko Bla ž evi ć Mentor: A. Ž mega č Horvat

2  The process of transformation from a normal cell to a cancerous one  Synonym: neoplasia Carcin ogenes is

3  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

4 NORMAL CELL growth factor growth factor receptor signal transduction activation of transcription cytoplasm nucleus DNA RNA Carcin ogenes is

5 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

6  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

7  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

8 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

9 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

10  Environmental agents  Heredity Carcin ogenes is

11  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

12  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

13  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

14  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

15  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

16  en.wikipedia.org/wiki/Carcinogenesis  4th year handouts  Google.com ... Carcin ogenes is


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