Transcript Lecture Powerpoint Here

CANCER - Why?
FIB Autumn 2008
Outline
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What is cancer?
Who can get cancer?
How does one develop cancer?
How can cancer kill you?
Which treatments exist?
1) What is CANCER?
• Cancer is a scary word
– Indeed there was a certain unwritten stigma
associated with death from the disease, until very
recently
– “…died after a long illness”
• Almost everyone knows someone who has
gotten very sick or died from cancer
• Most of the time, cancer affects older people
1) What is CANCER?..
• A good way to understand cancer is to
consider first, what happens to normal
cells
1) What is CANCER?…
• We are made of about 100 trillion cells
– 100,000,000,000 TRILLION
• Many of these are organized into tissues
– Which are aggregations of cells performing
common functions
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Liver
Pancreas
Brain
Blood
1) What is CANCER?….
• Our bodies are extremely good at managing all
these cells
• Such that the number of liver cells is more or less
constant, even though many die each day.
• Some tissue does not change much - nerves
• Other tissue has a very high rate of turn over i.e. immune system
– Many millions of cells die each day
– These are replaced by new ones made from existing
cells
1) What is CANCER?…..
• Every cell is told when to divide, so as to produce
more cells, and when to stop dividing
• This is known as the cell cycle
– Where one cell grows larger, copies its contents, and
then divides into two new cells
• Brain cells are given instructions never to divide
• Cell lining your gut divide almost constantly and
receive signals to perform the cell cycle daily
1) What is CANCER?……
• Any cell which no longer obeys the signals from your body
not to divide will begin to divide uncontrollably
• The loss of control over the cell cycle is a first necessary
step of cancer
• One cell growing uncontrollably divides to give rise to two
cells growing uncontrollably
• Each of these two cells divides to make two new cells
• Each of these cells divides again, etc, etc.
• ALL CANCER CELLS CAN GROW UNCONTROLLABLY
• Scientists refer to these local growths as tumors
– Tumors just grow at the site of the original disobedient
cell
1) What is CANCER?…….
• Some cells then undergo another
breakdown in communications
• They acquire the ability to break away
from the local tumor and leave
• They travel to other regions of the
body and start a new colony
• THIS IS CALLED CANCER
• Scientists call this a malignant tumor,
or cancer
1) What is CANCER?……..
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There are cancers of the;
Breast - many types
Brain - multiple types
Lung - many
Pancreas - hard to cure
Blood Bone In fact any cell can become cancerous
Cancer is a general term for many diseases
- all involving lose of cell control
1) So what is cancer in a nutshell?
• Cancer refers to any one of a large
number of diseases,
• all characterized by the development of
abnormal cells,
• which divide uncontrollably,
• and have the ability to infiltrate,
• and destroy normal body tissue
Fast Facts About Cancer
• One in three people will develop cancer.
• One in four people will die of cancer.
• In 2007, about 1.4 million new cases of
cancer were diagnosed.
• More than 1500 Americans died each day of
cancer this year.
• Over 1,000,000 cases of skin cancer will be
diagnosed this year.
• Cancer is the leading cause of death among
Americans under the age of 85.
2) Who can get cancer?
• Any organism made of cells
may loss control of the cell
cycle
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
2) Who can get cancer?..
• Generally the term cancer is reserved for multicellular organisms,
• where cells can travel to other regions and
disrupt the functionality of that tissue.
• So any multi-cellular organism can get cancer
2) Who can get cancer?…
• In fact we have fossils (such as those of
dinosaurs) which show cancerous
growths which may have killed that
animal
• Plants are also made of cells and
cancerous tumors can form there too.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
3) How does one develop cancer?
• It is now generally accepted that the
conversion of healthy obedient cells to
cancerous ones
happens due to two or more instances
of damage
to critical regions of the DNA of that cell
3) How does one develop cancer?..
• Once can consider the first defect
permits the cell to divide uncontrollably
– It loses control over the cell cycle
• The second defect allows the cell to
travel to distant sites
– It becomes metastatic
• Your body has a natural ability in
detecting many cancerous cells and
killing them before you know it.
3) How does one develop cancer?…
• Example A
– Breast cancer cells leave the breast tissue and
travel through the lymph to the bone
– There they start many many new colonies
– Eventually they become so large that they interfere
with the normal functioning of the bone tissue
• The patients’ bones break
• The patient cannot make new bone marrow products
• The amount of calcium in the body changes
3) How does one develop cancer?..
• Example B
– Lung cancer develops in the lung and spreads to
other regions of both lungs
– There they start many many new colonies
– Eventually they become so large that they interfere
with the normal functioning of the lungs
• The patient does not get enough oxygen
• The patient develops a lung infection
• The weakened patient cannot fight the infection and dies
3) How does one develop cancer?.
• The causes of this form of DNA damage
(mutation) are many and varied:
– Cosmic radiation
– Thermal heat - spontaneous
– Environment
– Diet
– Viruses
– Stress?
• This causes a failure in the chemical
regulation of the cell
4) How can cancer kill you?
• Firstly, it is important to understand that
not all cancers are fatal.
– Some patients live whole lifetimes
• Secondly, cancer at an early stage does
not kill you.
– That is why so much effort is put into early
diagnosis so that treatment is much more
likely to be effective
• Advanced cancers can and do kill!
4) How can cancer kill you?..
• Patients die either directly from the cancer
– Liver cells become cancerous and continue to
secrete large amounts of liver chemicals
– These upset the fine balances of the body
• Patients die either in-directly from the cancer
– Cancer cells disrupt the normal functioning of other
regions
– Weaken the body - blood vessels
– Increase infection - immune system depletion
Which treatments exist?
• Until recently, there were only three major treatments
options:
– Surgery
– Radiation
– Chemotherapy
• Now, there are many more materializing:
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Hormone Therapy
‘Magic Bullet’ drugs
Kinases - enzymes
The Kanzius Machine - Heat/radiation (60 minutes)
Which treatments exist?
Surgery - to remove the tumors
– If the tumor has not spread to other sites, one
can simply remove it along with some
surrounding tissue
– The patient will be cancer free and cured
– Must get it ALL before metastasis
Which treatments exist?
Radiation - to kill cancer cells by destroying
their DNA
Radiation therapy is the use of high-energy
penetrating rays or subatomic particles to
destroy the tumor
• The new equipment uses multiple beams at differing
angles to focus precisely on the tumor and its
immediate boundary
• Each beam is weak, but where they all meet is
deadly!
Which treatments exist?
Chemotherapy - use of very potent (cytotoxic) drugs
to kill all dividing cells - including non-cancerous
normal ones
The side effects can be daunting
• Loss of hair
• Lining of gut and mouth
• Anemia - Blood cells
Latest…
• The Kanzius Machine
Which treatments exist?
There are some promising new treatments appearing
at this time, but they are limited in scope and
fragmented at best - some patients respond better
then others.
Our video this week looks at a promising new and
controversial angle on tackling cancer…
Video Questions
1. How many days per week do the two patients
have to attend hospital?
2. What is one of the problems of using
chemotherapy?
3. How long ago did Dr. Judah Folkman first
realize the importance of blood vessels in
cancer biology?
4. What did the experiment on the eye show?
5. What does thalidomide have to do with this
story?
6. What happened to each of the two patients
followed by this story?
Group Questions
1. Do you know of someone who has had
cancer? Was it scary for them or you?
2. Cancer rates worldwide continue to rise
rapidly. Why?
3. Treatments of advanced cancers are not
considered cures, just remissions. Why?
4. Do you think we will ever eliminate cancers
in the future? Discuss.
5. Which kinds of lifestyle changes would
reduce your chances of developing cancer?