Cancer: Uncontrolled Cell Division

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Cancer Uncontrolled Cell Division

• Biology 12

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Some Stats from WHO

• Cancer is a leading cause of death group
  worldwide and accounted for 7.4 million deaths
  (around 13 of all deaths) in 2004. The main
  types of cancer are
• Lung (1.3 million deaths/year)
• Stomach (803,000 deaths)
• Colorectal (639,000 deaths)
• Liver (610,000 deaths)
• Breast (519,000 deaths)

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What is cancer?

• Cancer is a class of diseases characterized by
  out-of-control cell growth.
• There are over 100 different types of cancer and
  each is classified by the type of cell that is
  initially affected.

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What cause cancer at the cellular level?

• Cancer is ultimately the result of cells that
  uncontrollably grow and do not die, normal cells
  in the body follow an orderly path of growth,
  division, and death.
• Programmed cell death is called apoptosis, and
  when this process breaks down, cancer begins to
  form. Unlike regular cells, cancer cells do not
  experience programmatic death and instead
  continue to grow and divide. This leads to a mass
  of abnormal cells that grows out of control.

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How is a cancer cell different from a normal cell?

• Larger then normal nuclei (and/or multiple
  nuclei)
• Small cytoplasm
• Can grow in isolation from other cells
• Do not stick to the cells around them
• They may have abnormal numbers and types of
  chromosomes caused by mutations

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What causes the mutations that lead to cancer?

• Viruses (ex. HPV --gt cervical cancer)
• Bacteria (ex. H. pylori --gt gastric cancer)
• Chemicals (ex. Cigarette smoke --gt lung cancer)
• UV and ionizing radiation (ex. skin cancer)

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What can happen after a cancer cell forms

• Invasion a cancerous cell manages to move
  throughout the body using the blood destroying
  healthy tissue in a process
• Angiogenesis the cancer cell manages to divide
  and new blood vessels grow to supply it with
  blood
• Metastasis when a tumour successfully spreads
  to other parts of the body, grows, invading and
  destroying other healthy tissues
• Clip showing angiogenesis http//www.medicalnewst
  oday.com/info/cancer-oncology/

• Invasion a cancerous cell manages to move
  throughout the body using the blood destroying
  healthy tissue in a process
• Angiogenesis the cancer cell manages to divide
  and new blood vessels grow to supply it with
  blood
• Metastasis when a tumour successfully spreads
  to other parts of the body, grows, invading and
  destroying other healthy tissues
• Clip showing angiogenesis http//www.medicalnewst
  oday.com/info/cancer-oncology/

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How is cancer classified?

• There are five broad groups that are used to
  classify cancer.
• Carcinomas cells that cover internal and
  external parts of the body (ex. lung, breast, and
  colon)
• Sarcomas cells that are located in bone,
  cartilage, fat, connective tissue, muscle, etc.
• Lymphomas cancers that begin in the lymph nodes
  and immune system.
• Leukemias cancers that begin in the bone marrow
  and often accumulate in the bloodstream.
• Adenomas cancers that arise in the thyroid, the
  pituitary gland, the adrenal gland, and other
  glandular tissues.

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How is cancer treated?

• Depends on the type of cancer, the stage of the
  cancer (how much it has spread), age, health
  status, etc.
• Surgery
• Radiation
• Chemotherapy
• Immunotherapy
• Hormone therapy
• Gene therapy

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Cancer in Plants

• Not exclusive to humans
• Plant galls are abnormal outgrowths of plant
  tissues and can be caused by various parasites,
  from fungi and bacteria, to insects and mites.

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Cancer in Dinosaurs too?

• Many dinosaurs had cancer, researchers have
  discovered. Their tumours were like those of
  human patients, showing that cancer has been
  around for a very long time. "Diseases look the
  same independent of what critter is affected,"
  says radiologist Bruce Rothschild of the North
  Eastern Ohio Universities College of Medicine in
  Rootstown
• http//www.guardian.co.uk/science/2003/oct/23/dino
  saurs.science

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Animation

• http//www.youtube.com/watch?vqxcFbqA7w80

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To do

• Read page 100-102
• Complete practise questions 1, 2, 3
• Complete Section 3.5 questions 1, 2