Transcript Skin Cancer - Haiku Learning

Skin Cancer
Skin Cancer: The Facts
• The most common cancer in the United States
– Approximately 2 million people are diagnosed
annually
• The number one risk factor for skin cancer is
UV radiation exposure
– According to the American cancer Society, those
who begin indoor tanning before the age of 35
have an 87% increase in their risk of developing
melanoma
How the Sun Sees You
• How the Sun Sees You
A Little about the Sun
• The sun emits 3 types
of UV rays:
– UVA Rays:
• Not absorbed by the
ozone layer
• Penetrate deep into
the skin
• Contribute to
premature aging and
skin cancer
• Year-round damage
Over Exposure to UVA Rays
• This unidentified man
(from England) has been
a driver for 28 years.
– His skin has been gradually
thickening over the past
25 years
• UVA rays transmit
through clouds and
window glass to
penetrate the skin’s layers
and have been tied to
wrinkles and aging
A Little about the Sun
• UVB Rays:
– Reach the surface and
are the primary cause of
sunburn and skin cancer
– Only when the sun is hot
A Little about the Sun
• UVC Rays:
– Ozone and oxygen
absorb ALL UVC
rays and most UVB
rays
Sunscreen
• Designed to either absorb UV radiation or reflect UV
radiation
• SPF rating refers to the amount of time it would take
the sun to burn an individual with no sunscreen
compared to the time it would take to burn with
sunscreen.
– The SPF factor rates how effective the sunscreen is in
preventing sunburn caused by UVB rays. If you’d normally
burn in 10 minutes, SPF 15 means that by a factor of 15,
meaning you could go 150 minutes before burning
• Want a broad spectrum sunscreen that protects against
UVA and UVB rays
Skin Cancer Type
• Squamous Cell Carcinoma
– Develops in squamous cells found in the epidermis
– More common in individuals with fair skin
• Basal Cell Carcinoma
– Basal cells create the basement layer that nourishes the
epidermis
– Most commonly found in areas of the body with high sun
exposure
• Melanoma
– Develops in the melanocytes
– Least common type of cancer, but accounts for more than 75%
of all deaths from skin cancer
• How Skin Cancer Forms
Not an Old Person’s Disease
• Read Part 1 of Not an Old Person’s Disease and
respond to the following questions:
1. What are some differences between Judy
and Mariah that might make Judy more "at
risk" for skin cancer than Mariah?
2. What observations did Judy make concerning
her mole?
Skin Cancer
• Skin cancer is most simply abnormal growth of
epithelial cells and is most commonly found in
areas of skin with high sun exposure.
• UV radiation causes mutations in the DNA of
skin cells
• When these mutations occur in genes that
every healthy person has in order to make
more cells (cell cycle genes), uncontrollable
cell growth occurs.
Cell Cycle Genes
• Proto-oncogenes
– There are normal situations that arise when cells need
to grow and divide.
– Proto-oncogenes are responsible for initiating this
growth and division
– Normal genes can become cancer causing genes when
mutations occur in them that cause them to allow
cells to divide all the time
• Results in an abnormal mass of cells, or cancer, can occur
• The mutated forms of the normal proto-oncogenes are
called oncogenes
Cell Cycle Genes
• Tumor Suppressor Genes
– These genes make proteins that normally inhibit
cell division and prevent tumors from forming
– These genes tell cells to STOP growing and
dividing
– If both copies of a tumor suppressor gene have a
mutation, then your cells will not have that
normal control to stop them from dividing at an
inappropriate time
Skin Cancer
• There is a careful balance in normal cells
between the “cell-division-promoting” protooncogenes and the “cell-division-inhibiting”
tumor suppressor genes
• If this balance is tipped one way or another,
cancer can develop
Not an Old Person’s Disease
• Read part two of Not an Old Person’s Disease and
respond to the following questions:
1. Considering the differences between a benign tumor
and a malignant tumor, why might a benign tumor be
easier to treat?
2. Judy learned that every single person has these cell
cycle genes so cells in our body can divide when
necessary. What are some normal circumstances
where our bodies might need to make more cells?
3. Every person has these cell cycle proto-oncogenes,
but not every person has cancer. Why might this be
the case?
Not an Old Person’s Disease
• Read part 3 of Not an Old Person’s Disease and respond to
the final set of questions:
1. Now that you know a little more, what are the risk
factors that increase a person’s chances of having
melanoma?
2. How does sunlight contribute to the development of
melanoma?
3. What does it mean to be predisposed to getting cancer?
If you inherit a mutated cell cycle gene, does that
automatically mean that you will get cancer some day? If
you inherit a mutated cell cycle gene and participate in
risky behaviors such as sunbathing, does that mean you
will automatically get cancer some day?
Dear 16-year-old-me….
• Dear 16-year-old me...