1. Cancer
Lecture 2

2. CANCER CELLS Don’t respond to control signals
Lose density-dependent inhibition
Lose anchorage dependence
Telomerase enzymes maintain/replace telomeres
Transformation-
process that changes
a normal cell into
a cancer cell

3. Telomeres protect DNA from being degraded
Telomeres become shorter with each replication; shorter in older cells
Telomerase enzyme lengthens telomeres
Cancer cells have increased telomerase activity
2009 Nobel Prize Physiology/Medicine
Discovery of Telomeres
Jack Szostak Carol Greider Elizabeth Blackburn.

4. Most cells divide 20-50 times in culture; then stop, age, die
Cancer cells are “immortal” -HeLa cells from a tumor removed from a woman (Henrietta Lacks) in 1951 are still reproducing in culture