I.Cancer Cancer cells evolve and accumulate traits that distinguish them from normal cells causing them to form tumors cancer cellnormal cell Matthew Saelzler Graduate Student MIT

What is Cancer? How does cancer evolve from a normal cell? 1.What causes the change in a normal cell to make it into a cancer cell? 2.How many changes does it take to make a cancer cell? What do these changes in cells do?

DNA mRNA Protein mutant DNA mutant mRNA mutant Protein

The change into a cancer cell is not in one step. There are several changes to become a cancer cell normal cancer cellnormal cell cancer cell Each box represents a mutation in the DNA of the cell.

= normal cell = cancer cell

Main Concepts A. Cancer is caused by mutations in DNA. B.The change from a normal to a cancer cell is the result of several mutations. C.6 mutations give cancer cells abilities that normal cells lack Normal CellCancer Cell What do these changes in the normal cell do?

What does the mutation cause the normal cell to do? What happens next? The first mutation induces the cell to divide.

What does the second mutation do to the cell? activateinhibit What happens next? The second mutation blocks the cell from stopping division.

What does the third most likely do to the cell? Normal Cell Normal Cell Dies Cancer Cell Cancer Cell Lives Uncontrolled Growth Cancer cells can evade cell death (apoptosis). This mutation allows cells to inhibit apoptosis

What Makes a Cell a Cancer Cell? 1.Grow and divide without being told to do so. 2.Won’t stop growing and dividing when it should 3.It evades planned cell death What happens next?

What does the fourth mutation do to the cell? The cells must become immortal to form a tumor. Scientists have shown cells only divide a certain number of times. Once this is reached, they stop growing. The fourth mutation causes the cell to be immortal.

Angiogenesis - formation of new blood vessels -the tumor releases molecules that recruit cells that form the blood vessel -the recruited cells then form new blood vessels VEGF is a molecule released by tumor cells to recruit endothelial cells What is the fifth mutation required for a normal cell to progress to a cancer cell? Tumors need oxygen and nutrients to survive, therefore they must have the ability to recruit blood vessels.

What Makes a Cell a Cancer Cell? 1.Grow and divide without being told to do so 2.Won’t stop growing and dividing when it should 3.It evades cell death 4.It becomes immortal 5.It causes blood vessel formation What is next in the evolution of a tumor?

Metastasis-tumor cells move (spread) from one area of the body to another 1.Tumor cells grow at the primary site 2.The cells breakthrough and invade nearby tissue 3.The cells move into the bloodstream 4.The cells move from bloodstream somewhere else. 5.Tumor cells grow here into a tumor

Metastasis

What Makes a Cell a Cancer Cell? 1.Grow and divide without being told to do so 2.Won’t stop growing and dividing when it should 3.It evades cell death 4.It becomes immortal 5.It causes blood vessel formation 6.It can spread to other parts of the body What Makes a Cell a Cancer Cell? 1.Self-sufficiency in growth signals 2.Insensitivity to anti-growth signals 3.Evading Apoptosis 4.Limitless replicative potential 5.Sustained Angiogenesis 6.Invasion and Metastasis

Summary A. Cancer is caused by mutations in DNA. B.The change from a normal to a cancer cell is the result of several mutations. C.Mutations give cancer cells abilities that normal cells lack What do these changes in the normal cell do?