Causes of Squamous Cell Cancer

1. Exposure To Carcinogenic Factors

• Ultraviolet light - Most of this is from sunlight. Squamous cell carcinoma is most commonly seen in fair skinned individuals who are unable to tan and is associated with an accumulated lifetime exposure to sun. PUVA (Psoralen and Ultraviolet A radiation), which is used mostly for psoriasis, has an increased risk of squamous cell carcinomas
• Ionizing radiation such as radiotherapy may also increase of skin cancers
• Chemicals such as arsenic increase the risk of these skin cancers - exposure is usually chronic and at low concentrations
• Cigarette smoking increases the risks of squamous cell carcinoma by twofold
• Human Papilloma Virus is associated with squamous cell carcinoma in the genital area as well as around the nails

2. Genetic Syndromes

There are a number of genetic syndromes which increase the risk of skin cancers. These include xeroderma pigmentosa which is a defect in DNA repair. This condition is associated with sun sensitivity, extensive freckling and the risk of non-melanoma skin cancers is almost 5,000 times that of the normal population.

Individuals with ocular or cutaneous albinism which is a genetic disease with very little pigment also increase the risk of squamous cell carcinomas.

There is also a rare genetic disorder called epidermal dysplasia verruciformis which also has an increased risk of squamous cell cancers.

Other rare conditions such as dystrophic epidermolysis bullosa increase risk of squamous cell carcinomas.

3. Wounds

Chronic non-healing wounds such as chronic ulcers and thermal burns and other non-healing wounds have an increased risk of squamous cell carcinomas.

4. Immunosuppression

Individuals who are immunosuppressed such as after kidney or heart transplants are also at significant increased risk of aggressive squamous cell carcinomas.