VIII. CANCER = Uncontrolled Cell Division

Celebs with Cancer

B. Contact Inhibition- Normal cells will reproduce until they contact other cells.

- When this happens, they stop growing.

- Controls on cell growth and division can be turned on and off.

C. Cell Cycle Regulators

–Cell cycle regulated by cyclin» The amount rises and falls in

time w/ the cell cycle

–Cyclin: because it regulates cell cycle» Regulate the timing of cell

cycle in eukaryotic cells

Cyclins were discovered during a similar experiment to this one.

A sample of cytoplasmis removed from a cellin mitosis.

As result, the secondcell enters mitosis.

The sample is injectedinto a second cell inG2 of interphase.

D. Uncontrolled Cell Growth

Cancer is a disorder in which some of the body's own cells lose the ability to control growth.

How are cancer cells different

from other cells?

Cancer cells do not respond to the signals that regulate the growth of most cells.

i. Divide uncontrollablyii. Form masses of cells called tumors Metastasis: tumor cells break loose and

spread in body

The cells attract new blood vessel growth, this is called angiogenesis.

Tumor Types:

a. Malignant: some tumor cells are capable of escaping to a new part of the body – (metastasis).

B. Benign: tumor cells remain at original site. The cells lack the ability to spread. Can be removed surgically or killed by radiation

Biopsy:way to diagnose cancer by surgically removing piece of tissue and examining it

Staging:Describes the severity of a person’s cancer Aids in planning the treatment

E. Causes of Cancer:

• Genetics (~10% cause, cancer.gov)• Chemicals- asbestos, cigarettes, formaldehyde, dioxins, chlorine, pesticides• Radiation• Certain viruses (HPV) (Peyton Rous)• Poor Diet/ Obesity• Non- genetic causes are called carcinogens.

H. Mutations typically happen in two types of genes

1. Proto-oncogenes are normal genes that regulate cell growth Oncogenes are mutated

proto-oncogenes Ex : RAS

Stimulate cell division, inhibit differentiation, halt cell death(oncogenes increase production of proteins that do these things)

2. Tumor suppressor genes genes that stop the cell cycle or promote apoptosis

ex. p53 gene

F. Prevention of Cancer

Genetic screening BRCA 1 and BRCA 2 Avoid chemicals especially if they are classified as carcinogenic (cancer causing) Do not smoke, drink too much, proper diet, exercise, prevent sunburns, proper health screenings, organic foods