CANCER

Normal cells, with the proper medium and conditions, divide only until they come into contact with other cells. (MITOSIS)

At that point, cell division stops. This is known as Contact Inhibition.

Cancer cells do not:

… respond normally to the body’s control mechanisms

there are a number of reasons for this, some of which are:

Reasons:

• 1. They divide uncontrollably, invade other tissues if unchecked, and can kill the whole organism.

• 2. They divide indefinitely as long as nutrients are available.

• 3. They LACK Contact Inhibition.

Reasons (continued):• 4. The cells produced by this division

may form a Tumor, which can remain within the tissue in which it originated OR may begin to invade other tissue.

• 5. A cancerous tumor is said to be Malignant. If it is capable of invading other tissue it is also called Invasive. The spreading of the cancer is called Metastasis.

Reasons (continued):

• 6. If the tumor is non-cancerous, it is said to be Benign, which means that it does not grow in an unprogrammed way, but has the surface recognition proteins that keep it in its home area.

The Genetics of Cancer

Oncogene = any gene having the potential to induce a cancerous transformation.

They are altered forms of Proto-oncogenes that specify certain proteins necessary for normal cell function.

How does a proto-oncogene transform into an oncogene?

Mutations occur in proto-oncogenes (insertions, deletions)

A gene becomes abnormally amplified A whole gene can move to a new location on a

chromosome Chemicals that mutate DNA Viruses may circumvent the cells normal

proliferation controls

BOTH PLANT AND ANIMALS CAN GET

CANCER!

Characteristics Common to All Cancer Cells:

Number #1

Profound changes in the plasma membrane and cytoplasm.– Profound changes in the plasma membrane and

cytoplasm. Membrane permeability increases• Membrane proteins are lost or altered, different

ones form• Cytoskeleton becomes disorganized, shrinks,

or both• Enzyme activity shifts, as in amplified reliance

on glycolysis

Number #2

– Abnormal growth and division. Overcrowding control measures are lost Cell populations reach high densities Blood vessel growth is stimulated to the

growing cell mass

Number #3

– Weakened capacity for adhesion. Recognition proteins are lost or altered Cells can’t stay anchored in proper tissues

Number #4

– Lethality• Unless eradicated, cancer cells kill the individual

Kinds of cancer:

Sarcoma: tumors arising from cells in connective tissue, bone, or muscle

Carcinoma: tumors arising in epithelial tissue (skin)

Carcinogens = agents believed to cause cancer

Most Cancers are caused by exposure to a carcinogen

Other cancers have some genetic link

Common Exposure:

benzene, diesel exhaust, mineral oils, pesticides, cigarette tar

Uncommon Exposure:

asbestos, hair dyes, paint, soot, synthetic mineral fibers (wall and pipe insulation), Polychlorinated biphenyls (hydraulic fluids, lubricants, inks)

Rare Exposure:

Arsenic, formaldehyde (paper, textiles)

Cancer Cells vs. Normal Cells

Cancer Rates vs. Age

Incidences of Cancer

Incidence of Cancer in The United States in 2000

Type of Cancer New Cases Deaths % of Cancer DeathsLung 164,100 156,900 28Colon & Rectum 130,200 56,300 10Leukemia 93,100 49,200 9Breast 184,000 41,200 8Prostrate 180,400 31,900 7Pancreas 28,300 28,200 5Ovary 23,100 14,000 4Stomach 21,500 13,000 2Liver 15,300 13,800 2Nervous System 18,700 13,200 2Bladder 53,200 12,200 2Oral 30,200 7,800 2Kidney 31,200 11,900 2Cervix/Uterus 48,900 11,100 2Melanoma 47,700 7,700 1Sarcoma 10,600 6,000 1All other 139,400 77,800 14 Cancers

In 2000: there were 1,220,100 reported cases of new cancers and 552,200 Cancer deaths.

Questions:1. Which types of cancer have the highest death rate?

2. Which types of cancer have the lowest death rate?

3. In 2000, roughly what percentage of people who had cancer diedfrom the disease?

4. Which is the biggest killer among cancers?

5. Which cancers appear to be age related?

Cancer Radiation Treatment

is a cancer treatment that uses high doses of radiation to kill cancer cells and stop them from spreading.

At low doses, radiation is used as an x-ray to see inside your body and take pictures, such as x-rays of your teeth or broken bones. Radiation used in cancer treatment works in much the same way, except that it is given at higher doses.

Radiation Treatment

Given in high doses, radiation kills or slows the growth of cancer cells. Radiation therapy is used to:

Treat cancer. Radiation can be used to cure, stop, or slow the growth of cancer.

Reduce symptoms. When a cure is not possible, radiation may be used to shrink cancer tumors in order to reduce pressure. Radiation therapy used in this way can treat problems such as pain, or it can prevent problems such as blindness or loss of bowel and bladder control.

Radiation Treatment Radiation not only kills or slows the growth of

cancer cells, it can also affect nearby healthy cells. The healthy cells almost always recover after treatment is over. But sometimes people may have side effects that do not get better or are severe.

Using as low a dose of radiation as possible. Spreading out treatment over time.

Chemotherapy

is the treatment of cancer with drugs that can destroy cancer cells. These drugs often are called "anticancer" drugs.

Healthy cells can also be harmed, especially those that divide quickly. Harm to healthy cells is what causes side effects. These cells usually repair themselves after chemotherapy.

Chemotherapy

To cure the cancer. Cancer is considered cured when the patient remains free of evidence of cancer cells.

To control the cancer. This is done by keeping the cancer from spreading; slowing the cancer's growth; and killing cancer cells that may have spread to other parts of the body from the original tumor.

To relieve symptoms that the cancer may cause. Relieving symptoms such as pain can help patients live more comfortably.

Curing Cancer

Monoclonal Antibodies: created through genetic engineering, uses the bodies immune system to attack the cancer cells

Farnesyl Transferase Inhibitors: induces tumor regression and prevents the growth of new ones

“Anti-sense RNA”: blocks normal protein synthesis of cancer cells, no longer function as viable cells

Curing Cancer

Adenovirus: blocks the host cell machinery Inhibiting Telomerase: chromosomes lose

telomeres without this enzyme, chromosomes “clock” is stopped, cancer cells stop reproducing

Angiogenesis Inhibitors: Drugs such as Endostatin & Angiostatin that cut off the blood supply to cancer cells effectively starving them