How Cancer Works

Cancer is the 2nd leading cause of death in the U.S. This year over ½ a million Americans will die of cancer #1 cause of death in the U.S. is ____________ http://www.cdc.gov/nchs/fastats/deaths.htm

What is Cancer? Cancer is out-of-control cell division of mutated (abnormal) cells Normally, cells divide in a timely and orderly fashion. Also, if a cell is damaged it will not divide and will actually self-destruct

What is a Tumor? Is it Cancer? Tumor = a mass of tissue that forms when cells divide at an accelerated rate

Pics of Tumors Osteosarcoma (cancerous bone tumor)

Pictures of Tumors Brain Tumor

Tumors can cause destruction in 3 major ways Put pressure on nearby tissues/organs Invade tissues and organs directly and damage or destroy them Make invaded tissue more susceptible to infection

Not all Tumors are Cancerous Benign Tumors = tumors that are NOT cancerous Will not spread to other parts of the body Usually will not grow back once it is removed However, can still be very dangerous and harmful

Cancerous Tumors Malignant Tumors = these ARE cancer Can spread to other tissues/organs More likely to come back after it is removed

Benign vs. Malignant Tumors

How Cancer Spreads Metastasis = the spreading of cancerous cells Millions of cancer cells are released from the site of the tumor into the blood stream

Breast Cancer

Metastasis

Metastasis

Stages of Cancer

Understanding the Cause of Cancer Cancer occurs when the cell cycle becomes unregulated Cell Cycle = a timely cycle of growth and replication of a cell

Understanding the Cause of Cancer Checkpoint Proteins act to ensure that: Stages of the cycle happen at the proper time There are no mistakes If a checkpoint protein detects that something is wrong, the cell will not divide!

Cell Cycle Checkpoints

Cell Cycle Checkpoints

Understanding the Cause of Cancer Cancer results from a breakdown in these checkpoint proteins They are not doing their job and therefore the cell divides when it should not

Understanding the Cause of Cancer Why do the checkpoint proteins break down? DNA is the “instruction book” for making these proteins If there is damage to the DNA, then checkpoint proteins may not be made or will be made incorrectly

Understanding the Cause of Cancer If the DNA makes nonfunctional checkpoint proteins: There will be too much cell division Division will occur even though there are major errors/damage

Genetic/Natural Causes of Cancer What causes DNA mutations? (Changes in the DNA message) You can inherit faulty genes from your parents Genes may mutate (accidentally) in your cells over time Mistakes can be made when DNA copies itself in preparation for cell division

Understanding the Cause of Cancer What causes DNA mutations? (Changes in the DNA message) Carcinogens = a cancer-causing substances or exposures

Examples of Known Carcinogens Tobacco smoking Smokeless tobacco (chew) UV Radiation X-rays and gamma rays Asbestos Wood Dust Alcoholic Beverage Consumption

Examples of Known Carcinogens HPV (Human Papilloma Virus) Hepatitis B Hepatitis C Soot Silica (that is small enough to be inhaled) Coal Tar Estrogen Steroids Chemicals used in furniture and cabinet making

Carcinogens in Cigarettes There are 81 known carcinogens in cigarettes!!

Healthy Lung Lung Cancer

Cancer Treatments Surgery – remove the tumor

Cancer Treatments Radiation Therapy X-rays are directed precisely at the tumor site X-rays kill the cells by damaging the DNA

Cancer Treatments Chemotherapy – uses chemicals to kill fast-growing cells in the body Can shrink/eliminate a tumor Can kill cancer cells that have metastasized Can kill cells in any part of the body