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The Genetics of Cancer

The Genetics of Cancer. Bashdar M. Hussen MSc.Biotechnology Hawler Medical University bashdar@res.hmu.edu.iq bmhscience@yahoo.com. Cancer in the media. Human and Cancer Life and adaptation cell division. cancer is a disease of the cell cycle. Cont. Of RNA. Synth. Of RNA & proteins.

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The Genetics of Cancer

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  1. The Genetics of Cancer BashdarM. Hussen MSc.Biotechnology Hawler Medical University bashdar@res.hmu.edu.iq bmhscience@yahoo.com

  2. Cancer in the media Human and Cancer Life and adaptation cell division

  3. cancer is a disease of the cell cycle Cont. Of RNA Synth. Of RNA & proteins

  4. G1 checkpoint DNA damage or broken Chromosomes are attached to the spindle Control system S G1 G2 M In complete DNA replication M checkpoint G2 checkpoint

  5. G0 G1 checkpoint G1 G1 If a cell does not receive a go-ahead signal at the G1 checkpoint, the cell exits the cell cycle and goes into G0, a nondividing state. If a cell receives a go-ahead signal at the G1 checkpoint, the cell continues on in the cell cycle.

  6. Unlimited number of cell divisions.Growth without external signals.Failure to respond to 'stop' signalsAvoidance of cell death.The ability to leave the original tumor location and form a new tumor, or metastasis.

  7. Cancer terminology Classification by tissue type: • carcinomaepithelial cell90% of all tumoursderived from ectoderm (mostly) or endoderm (some) • sarcomaconnective tissue2% of all tumoursderived from mesoderm • leukaemiacirculatory or lymphatic8% of all tumoursderived from mesoderm • Myeloidblood cell • Lymphoidlymphocytes or macrophages • Central nervous system cancers of the brain

  8. Main Features of Benign and Malignant Tumors

  9. Cancer Spreads Step-by-Step

  10. A Common Type of Colorectal Cancer May Develop by These Steps

  11. Types of genes which may mutate to cause cancer: • Tumor suppressor genes • Stop cell growth and division; prevent cancer formation • May prevent expression of oncogenes • Retinoblastoma: only one functional copy of a tumor suppressor gene on chromosome 13 • BRCA1 and BRCA2 • p53: codes for a regulatory protein that turns off cell division when the cell is stressed or damaged

  12. Type of gene Normal function Mutated function Types of proteins Promotes division - abnormal time or cell type Growth factors Oncogene Promotes division Tumor suppressor gene Suppresses cell division Fails to suppress division Checkpoint molecules DNA repair gene mutation Repair DNA mutations Fail to repair DNA mutations Enzymes for mismatch or excision repair Types of cancer genes

  13. Tumour suppressor genes • The gene’s normal function is to regulate cell division. Both alleles need to be mutated or removed in order to lose the gene activity. • The first mutation may be inherited or somatic. • The second mutation will often be a gross event leading to loss of heterozygosity in the surrounding area.

  14. Oncogenes • Cellular oncogene c-onc • Viral oncogene v-onc • Proto-oncogene, activated by mutation to c-onc

  15. Proto-oncogene activation

  16. Other Factors Also May Lead to Cancer • Inherited susceptibility to cancer • ~5% of cancers • Viruses • Viral DNA may be inserted into a host cell’s DNA • May switch on a proto-oncogene • May carry oncogenes

  17. Other Factors Also May Lead to Cancer • Chemical carcinogens • Carcinogens: cancer-causing substances that can lead to a mutation in DNA • Hydrocarbons in cigarette smoke • Aflatoxin: fungal product • Radiation • UV from the sun and tanning lamps • X-rays: medical and dental • Radon, cosmic rays, and gamma radiation

  18. Some Industrial Chemicals Linked to Cancer

  19. In the U.S., More than 1 Million People Are Diagnosed with Cancer Each Year

  20. Biopsy Is the Only Sure Way to Diagnose Cancer • Biopsy • Removal and microscopic examination of tissue

  21. Light Microscope Image Shows Cancerous Cells in Breast Tissue

  22. Cancer Treatment and Prevention • When a person is diagnosed with cancer, a variety of weapons are available to combat it • Chemotherapy drugs • Radiation therapy • Surgery

  23. Chemotherapy and Radiation Kill Cancer Cells • Chemotherapy • Drugs used to kill cancer cells; disrupt some aspect of cell division • Toxic to healthy cells; hair, bone marrow, lymphocytes, and epithelial cells of intestinal lining • Side effects include hair loss, nausea, vomiting, and reduced immune responses • Genetic approach to chemo in the future

  24. Chemotherapy and Radiation Kill Cancer Cells • Radiation therapy • Used when cancer is small or has not spread • Radioisotopes used, e.g., Ra-226 and Co-60 • Chemotherapy and radiation destroy healthy cells • More precise treatments • Monoclonal antibody treatment • Interferontreatment; limited at present

  25. Good Lifestyle Choices Can Limit Cancer Risk • Avoid tobacco completely • Maintain a desirable weight; eat a low-fat diet with plenty of fruits and vegetables • Drink alcohol in moderation • Make sure your living and work environment is safe from carcinogens • Protect your skin from the sun’s UV rays

  26. This Cancer Cell Is Surrounded by White Blood Cells

  27. Cancer Causes and Contributing Factors

  28. What mark have you thought to leave after?

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