Transcript Cancer - AHSbognasnc4m

CANCER
- a public health issue
epidemiology
• the study of the patterns, causes, and effects of
health and disease conditions in defined
populations
• informs policy decisions and evidence-based
medicine
– identifies risk factors for disease
– targets for prevention
• Epidemiologists help with study design, collection
and analysis of data, and interpretation and
distribution of results
Canadian Cancer Statistics 2013
Canadian Cancer Statistics 2013
Canadian Cancer Statistics 2013
Canadian Cancer Statistics 2013
Cancer in Canada
Cancer Risk Factors
There are many known risk factors for cancer:
• Tobacco Use (30%)
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almost 30% of all fatal cancers in Canada
major cause of lung cancer
• Poor Diet/Obesity/ Lack of Exercise (30%)
• one with a high proportion of dietary fat, about 20% of
fatal cancers
• Colon and prostate cancers are associated with diets
high in fat
http://www.youtube.com/watch?v=aUaInS6HIGo&featur
e=c4-overviewvl&list=PL4TcyUrQ3YhJ4X5kajWcx9myxoLfx_zt-
• Other Risks (30%)
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workplace hazards
family history
alcohol use
reproductive factors
sexual activity
sunlight/ ionizing radiation
drugs
Reducing your risk
• Live well. Make healthy choices.
• Be a non-smoker and avoid second-hand smoke.
• Keep a healthy body weight. Be active and eat well.
• Know the risks of alcohol.
• Protect your skin.
But…What’s causing cancer?
• A look inside the nucleus
• Multi cellular organisms = billions of cells
• cells need to divide and copy themselves for a variety of
reasons.
For example:
– cells wear out and need to be replaced
– new cells allow the body to repair damaged tissue
– new cells allow the body to grow
Cell Division
- The most common form of cell division is mitosis
- Occurs in all body cells and is used for growth and
repair
- cell makes an exact copy of itself and splits into two new
cells
- Each cell contains an exact copy of the original cell’s
DNA: this is the reason why all the cells in an organism
are genetically identical
• Cell division occurs through a copying of its
genetic information
• At the end of mitosis you end up with two identical
(daughter) cells, each carrying the same DNA
http://www.youtube.com/watch?v=Q6ucKWIIFmg
But…what’s so important about DNA?
• In a cell all functions are carried out by proteins:
control of cell reproduction, production of energy,
production of hormones, production of digestive
enzymes, etc.
• DNA contains genes: the blueprints for those
proteins
• Each gene is an assembly guide (think IKEA) on
how to put the protein together
DNA RNA protein
Central Dogma of Molecular Biology
DNA  RNA  protein
• If there is a mistake (mutation) in the blueprint, in
the DNA, there will be a mistake in the protein
• Most times the cell will detect the mistake and
die:
Figure 9.21 Apoptosis: Programmed Cell Death
When cell division goes wrong
• Cell division is tightly controlled by genes inside
the nucleus.
• Special genes, called oncogenes, stimulate cell
division
• If through a mutation an oncogene is irreversibly
switched “on” it can cause uncontrolled cell
division
CANCER = uncontrolled cell division
• Cells divide, divide, and divide…
http://www.youtube.com/watch?v=IeUANxFVXKc
www.microscopyu.com/moviegallery/livecellimaging/3t3/index.html
tumour
• The uncontrolled growth of cells forms a lump called a
tumour.
– Some tumours are benign and may not cause any
problems.
– Others are malignant. They can invade into other
body tissues and cause severe damage. It is these
malignant tumours that we call cancer.
• There are over 200 different types of cancer and they
can occur anywhere in the body.
Cancer Treatments
1.
Surgery
- Effective for tumours in a defined area, often the first
treatment
1.
Chemotherapy
- Medication used to target and kill quickly-dividing
cancer cells: some prevent new cells from splitting
apart, while others stop the production of new DNA
2.
Radiation therapy
- high-energy radiation is aimed at the growing tumour
to damage its DNA
3.
Some combination
• http://www.hhmi.org/biointeractive/cancer/angioge
nesis.html
What do you think?
A new genetic screening test for some cancers
could allow for the identification of people who are
at higher risk. Even if the test is positive, the
person may never develop cancer. Do you think
such a test should be available and if so, should it
be publicly funded?
What do you think?
Certain cancer are linked to lifestyle choices (i.e.
smoking), some people think that public health
care dollars should not support the treatment of
these types of cancers (at least not 100%) and
that there is a certain degree of personal choice
and responsibility.