BIO 226W
Nazareth College

Skin Cancer

        The skin is the body's largest organ.  The visible portion of the skin is called the epidermis.  The bottom row of cells is composed of basal cells and the middle layer consists of squamous cells.  Melanin producing melanocytes are interspersed between them.  Squamous cells are fast growing cells that have matured and moved upward from the basal layer.

RISK FACTORS:

• fair skin

• green or blue eyes

• skin that blisters easily, burns readily, and tans poorly

• hereditary: family history of a malignant melanoma

• people exposed to x-rays, coal tars, arsenic, or thermal burns

• people who live in the South or Southwest

• those who live in high altitudes (more UVB light)

• people who are exposed to the sun for long periods of time, farmers, athletes, lifeguards, and sun worshipers (2)

• congenital nevi-moles present at birth or prior to 6 months

• doctors believe that medium to large moles should be removed because of high risk of developing melanoma

        Skin cancer takes decades to develop and the effects of ultraviolet radiation (UVB from the sun as well as UVA get blistering sunburns) are cumulative therefore, sunbathing even for a few weeks each summer for 20 or more years amount to considerable exposure.  If you develop a searing sunburn in the first 10-15 years of your life the chances of developing a malignant melanoma are tripled (2).

        Tanning beds are another cause of skin cancer.  UVA rays are only found in tanning beds and do not cause sunburns.  UVA rays penetrate more deeply.  These long waves penetrate to the dermis which is where the long term damage occurs.  Collagen is lost, your blood vessels decrease in numbers, and the connective tissue of the dermis is altered.

• A biopsy for suspected skin cancer involves the removal and microscopic examination of the suspected tissue. 
• Cryosurgery: freezing of the area 
•  Electosurgery is the destruction of tissue through the use of frequency electric currents.
• Chemotherapy: 5FU (5 Fluorouracil) used as a topical cream or lotion eradicates visible precancerous lesions but actually seeks out and destroys those that remain hidden below the surface of the skin.
• Radiation therapy involves directing beams at malignant cells, damaging and often killing them.
• Laser surgery: extremely concentrated source of light, so much heat is given off it destroys anything in its path.
• Chemosurgery, (MOHS surgery):  strong chemical such as zinc chloride applied and left on for 24 hours during which it kills cancer cells and is repeated until all the cancerous cells are removed.
• Immunotherapy: attempts to stimulate and strengthen the body's own natural defense for protection against and recovery from disease (2).
• Treatment of metastatic melanoma: surgery radiation treatment if  it is in the brain or the bone and chemotherapy if it is widespread or distant, especially in the lungs or liver.  This is usually given through IV's.
• Interleaken - immunotherapy treatment: for medication in small amounts  in the body by T cells.  When a T cell encounters a foreign antigen it is activated to produce Interleaken 2 which activates killer cells which merge with cancerous cells and kills them.
• New developments for patients with advanced melanoma is a vaccine.  The purpose is to increase a person's immunity against some foreign invader.  It is hoped that there will be a vaccine someday for at risk people (2).

        It is recommended by the American Cancer Society, The Skin Cancer Foundation, and The American Academy of Dermatologists to have a total body skin examination once a year.  Wearing a hat and sunglasses with ultraviolet protection and wearing a SPF sunscreen of 15 or greater from infancy to age 18 can also help,  and avoid tanning beds and sunbathing (2).

Nazareth College
Rochester, New York