Lecture 12-04 Cancer Genetics

Lecture 12-04 Cancer Genetics - Cancer Genetics There not...

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Cancer Genetics - There not one thing that makes a cancer cell different from a normal cell - There are a number of characteristics that are typical for normal cells and the same for cancer cells. - The characteristics of most normal cells and how they differ from the: characteristics of many cancer cells. Characteristics of Most Normal Cells Characteristics of Cancer Cells - Limited number of divisions (without active telomerase, their telomeres get shorter with every division) - Growth factor dependent (made with serum that is a derivative of blood because it contains hormones that signal the cell to divide)—the reason why most normal cells are GF dependent is because they don’t stimulate their own division, - Undergo apoptosis when damaged —self suicide (normal mechanism by which a cell can just shut itself down and kill itself; important in cells that become damaged) - Have normal Karyotype - Immortal (active telomerase), - Growth factor independent—they stimulate their own cell division by producing a growth factor AND the receptor for the same growth factor - won’t undergo apoptosis - Cancer cells have sever aneuploidy —euploidy is having the true number of chromosomes and aneuploidy is having extra (usually) chromosomes are being short of the norm - With such genetic instability, we can explain why cancer starts out a little slow and become aggressive overtime. - Many mutations lead to a normal cell changing into a cancerous cell (this is why it takes time) - A cell becomes cancerous when it has accumulated the 7-10 characteristics specific to a cancer cells and it takes a while until the cell begins to affect the individual. - One severe burn when you’re young greatly increases your risk of cancer many years down the line. The mutations at that one moment in time wasn’t enough to cause cancer, but these mutations may accumulate later on to become cancerous - Three Sources of these cancerous mutations o May be caused by exposure to mutagens o It may come from a virus, not just any viral infection, but specific viruses that can cause cancer. o Ex – HPV (Human Papilloma Virus), Burkettes (cats)--Feline leukemia, Hepatitis (causes liver cancer) - People don’t usually inherit 7-10 mutations, but usually just one (this one mutation is in every cell in the body) - But it also depends on where these mutations lie (its mutations that control cell division that disrupts the cell’s ability to control cell division and lead to cancer)
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o Cells lose a little bit of control over time (one or two mutations may develop but it still isn’t normal) o The cell may be dividing a little faster, or may divide at inappropriate times. o
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This note was uploaded on 12/04/2008 for the course BIO 325 taught by Professor Saxena during the Fall '08 term at University of Texas.

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Lecture 12-04 Cancer Genetics - Cancer Genetics There not...

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