Cancer

Cell in which controls on the cell cycle have broken down due to mutations

-          often see mutations in genes for proteins controlling cell cycle

-          this is why cancers nearly always arise from tissues in which there is proliferation

o       neurons and muscle cells rarely divide, so cancers of these are rare

-          however, even in a tissue like liver, where most cells are differentiated and don’t proliferate, can get cancer

o       these may arise from stem cells

§         long-lived, can replace dead cells

Multiple hit hypothesis

-          takes more than one mutation in a cell to transform it into a cancer cell

-          find all kinds of chromosomal abnormalities in cancer cells

o       so genome is unstable and seems to accumulate mutations faster than other cells (maybe…..)

Look at colon cancer progression

What are some characteristics of cancer cells?

-          autocrine stimulation

-          loss of contact inhibition

-          loss of cell death when appropriate

-          activation of telomerase (immortality)

-          ability to metastasize

-          angiogenesis

-          genomic instability

o       replication problems, esp in mismatch repair

o       other gross rearrangements