Genes found in every cell that control growth, repair, and replacement. Abnormalities of oncogenes are known to be a factor in the development of cancerous cells. Mutations in oncogenes, resulting from damage by carcinogens, can cause a cell to grow unrestrainedly and infiltrate and destroy normal tissues (see cancer). Factors known to cause cancer include ultraviolet light, radioactivity, tobacco, alcohol, asbestos, some chemicals, and certain viruses.


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