Cancer

Cancer is caused when something affects the genetic material of our cells. This causes the cells to reproduce in an uncontrollable manner producing a lump of tissue, known as a tumor.

There are two types of tumor:

• benign - where the cancerous cells do not have the ability to spread beyond the tumor, and
• malignant - where the cells can spread beyond the tumor and affect other parts of the body.

Over-exposure to sunlight

The leading cause of skin cancer is over-exposure to sunlight. The sun is essentially a gigantic nuclear fusion reactor that pumps out massive amounts of radiation in the form of light and heat.

We are protected from most of this radiation by the earth's atmosphere. However, sunlight contains two wavelengths of radiation that can affect the cells in our skin: Ultraviolet A (UVA) and Ultraviolet B (UVB).

It is thought that UVA causes alterations (mutations) in the cells of our skin that produce the chemical melanin (substance that gives our skin its color). These mutated cells can then become cancerous and cause melanomas to develop. UVB can also cause mutations in the upper skin layers leading to basal cell and squamous cell carcinomas.

Artificial sources of light, such as sun lamps, and tanning beds, produce UVA so over-use of these appliances will also increase your risk of getting skin cancer.

Genetic causes

Research suggests that you can be genetically predisposed to developing skin cancer (you can inherit it from a family member). And, if you have two, or more, close relatives who have had skin cancer, your chances of developing the condition may be increased further.

Risk factors

Risk factors for developing skin cancer include:

• having pale skin that does not tan easily,
• having red, or blonde, hair,
• having blue eyes,
• having a large number of moles,
• having a large number of freckles, and
• having a condition that suppresses your immune system, such as HIV, or taking medicines that suppress the immune system (immunosuppressants).

All these risk factors will make your skin more sensitive to the effects of the sun.

Other causes

In some rare cases, skin cancer can also be developed from exposure to certain substances including:

• coal tar,
• soot ,
• pitch,
• asphalt,
• creosotes,
• paraffin waxes,
• petroleum derivatives,
• hair dyes,
• cutting oils, and
• arsenic.

You should ensure you wear adequate protective clothing if your profession involves prolonged exposure to any of these substances.