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