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Notes on the Genetics of Cancer. Part 1 - Jan 22, 2007. What is Cancer?. What is Cancer?. “ The Disease caused by uncontrolled division of abnormal cells in a part of the body.”. Cancer Cells. Undergo constant cell division (~ every 2 days) and never enter G 0. Cancer Cells.
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Notes on the Genetics of Cancer Part 1 - Jan 22, 2007
What is Cancer? • “The Disease caused by uncontrolled division of abnormal cells in a part of the body.”
Cancer Cells • Undergo constant cell division (~ every 2 days) and never enter G0.
Cancer Cells • Undergo constant cell division (~ every 2 days) and never enter G0. • No adhesion dependence (don’t need to be attached to another cell)
Cancer Cells • Undergo constant cell division (~ every 2 days) and never enter G0. • No adhesion dependence (don’t need to be attached to another cell) • No density dependence (continue to divide even when surrounded by other cells to form a 3D tumor)
Cancer Cells • The are de-differentiated (your 200+ cell types all look the same when cancerous and lose their function)
Cancer Cells • They invade other tissues (local or metastasis)
Cancer Cells • They invade other tissues (local or metastasis) • They are angiogenic (they cause the creation of new capillaries to bring blood to the tumor).
Cancer Treatment • The best offense is a good _________
No smoking Avoid BBQ High fiber foods Fresh veggies Wear sunblock Mole watch Self-examination Colonoscopy Prevention and Detection
Treatments • Excision: removal of tumor (lumpectomy) and surrounding tissues (radical), including lymph nodes
Treatments • Chemotherapy: drugs that target rapidly dividing cells, such as a cancerous tumor, but unfortunately include hair follicles, dermal cells that create skin, and the lining of the digestive system.
Treatments • Radiation: destroys DNA and stimulates apoptosis (intentional cell death) via activation of the p53 gene (tumor suppressor gene). • Anti-angiogenesis drugs • Anti-telomerase drugs
The Genetics of Cancer • Mutation in cell cycle genes > loss of control of cell cycle • 2 (colon) to 15 (lung) gene mutations are required for cancer to happen
Protooncogenes • These genes stimulate cell division (repair and replacement of cells). • Dominant alleles (only 1 needed), so only 1 mutation necessary • Once mutated and stuck in “on” position, called “oncogenes” (onco=cancer) • Protooncogene = gas pedal
Tumor supressor gene • TSG’s arrest cell division. • Recessive alleles, so two mutations needed for effect (cancer). • TSG’s = brakes
POGs + TSGs • So….if you have a mutation of a POG and both copies of the TSG, it is like gluing the gas pedal to the floor and disconnecting your brakes. Not good.