Transcript Notes on the Genetics of Cancer

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 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 _________
Prevention and Detection
•
•
•
•
•
No smoking
Avoid BBQ
High fiber foods
Fresh veggies
Wear sunblock
• Mole watch
• Self-examination
• Colonoscopy
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.