Ozone Loss and Skin Cancer

Problem• 1986 - Susan Solomon found the

correlation between the disappearance of ozone and increased concentration of chloroflurocarbons (CFC’s)

• CFC’s – Refrigerants popularized in industry

during the 1950’s – During the winter months concentrates

in the South Pole, then reacts with ozone during the Spring months

– Overall decrease in ozone concentration

Repercussions

• 1992, projected 5% yearly decrease in ozone layer

• Increased UV penetration, increased exposure

• Effects of increased exposure– Immune system suppression– DNA damage– Irreversible ecological changes– Increased skin cancer rates

Types of Skin CancerMelanoma – cancer of the

melanocytes (pigment producing cells on the skin)

Non Melanoma Basal Cell Type – cancer of the basal cell layer (lower)

Squamous Cell Type – cancer of the squamous cell layer (upper)

Melanoma

-most severe most rapidly growing of the three cancers-irregularly shaped, dark moles; usually starts with the darkening, then becomes metastatic

Basal Cell Carcinoma

- basal cell layer, separates epidermis from the dermis - most common; presents as small fleshy nodules on the skin - slow developing and rarely metastesize if diagnosed and treated early

Squamous Cell Carcinoma

-squamous cell layer – layer of skin separating the dead skin layer from the basal cell layer-develops more quickly than basal cell carcinoma and has a greater tendency to metastesize -can present as nodules or scaly, read patches and can ulcerate and bleed; most commonly found on fairer skinned individuals

Facts“Every blistering sunburn doubles the likelihood of skin cancer formation”

“1 percent reduction in ozone leads to a 2 percent increase in UV intensity. The research further indicates that a 2 percent increase in UV intensity leads to a 2 to 4 percent increase in skin cancers”

“…people with red hair, fair skin, and freckles have the highest risk, But people who carry one gene for this high-risk trio also face an increased risk of skin cancer, even if their skin color is olive”

Why?

Free radicals [due to UV rays exposure] are very reactive molecules… believed to produce DNA mutations that can lead to skin cancer.

Risks – Skin Type

Type I Fair skin, blue or green eyes, little or no freckles.

Burns and peels severely.

Type II Fair skin, blue eyes, blond or brown hair. burns severely and

easily peels, tans minimally.

Type III Fair skin, brown hair, brown eyes.

Burns moderately, tans somewhat.Type IV

 Olive or light brown skin,

dark brown hair, dark eyes. Burns minimally, tans easily.

 Type V Dark brown skin.

Rarely burns, tans easily and substantially.

Type VI Black or dark brown skin, brown eyes, black or dark

brown hair. Burns only with severe exposure.

 

Type CharacteristicsRoutine day 

Outdoor Activity

I Always burns easily, never tans 15 25-30

II Burns easily, tans slightly 12-15 25-30

IIISometimes burns, tans gradually and moderately 

8-10 15

IV Burns minimally, always tans well 6-8 15

V Burns rarely, tans deeply 6-8 15

VI Almost never burns, deeply pigmented 6-8 15

Risks Cont.Suggested SPF

Preventive Measures

Sunscreen SPF (sun protection factor)

- SPF of n means it will take n times longer to acquire erythema (sunburn)- SPF of 15 ususally recommended

Antioxidants - Vitamins: Retinol (A), absorbic acid

(C), tocopherol (E) - Help inhibit peroxidative damage

caused by free radical formation

Preventive Measures Cont.

“Scientists have synthesized an artificial enzyme they believe can repair sun-damaged DNA, the cause of many skin cancers. Although promising, they emphasize that much more research needs to be done before it's known if the enzyme can be used to protect people. Particular molecules, known as thymine dimers, are formed in DNA as a result of ultraviolet radiation. These dimers are a "major cause of skin cancer," according to Jonas. Simply put, the enzyme works by attaching itself to the dimers and breaking them down, thus reversing the damage caused by UV light before cancer develops.”

Cancer Weekly, April 17, 2001 pNA Reversing DNA Damage Caused By The Sun May Be Possible

Biochemical Approaches

Conclusion

-Definite increase in UV rays exposure

-Direct correlation with increased cancer rates with increased sun/UV exposure

-Measures taken are primarily preventive although biochemical exploration is underway