There is no one single cause for cancer. Scientists believe that it is the interaction of many factors together that produces cancer. The factors involved may be genetic, environmental, or constitutional characteristics of the individual.
Cancer Risk Factors
- Lifestyle factors. Smoking, a high-fat diet, and working with toxic chemicals are examples of lifestyle choices that may be risk factors for some adult cancers. Most children with cancer, however, are too young to have been exposed to these lifestyle factors for any extended time.
- Family history, inheritance, and genetics may play an important role in some childhood cancers. It is possible for cancer of varying forms to be present more than once in a family. It is unknown in these circumstances if the disease is caused by a genetic mutation, exposure to chemicals near a family’s residence, a combination of these factors, or simply coincidence.
- Some genetic disorders. The immune system is a complex system that functions to protect our bodies from infection and disease. The bone marrow produces cells that later mature and function as part of the immune system. One theory suggests that the cells in the bone marrow, the stem cells, become damaged or defective, so when they reproduce to make more cells, they make abnormal cells or cancer cells. The cause of the defect in the stem cells could be related to an inherited genetic defect or exposure to a virus or toxin.
- Environmental exposures. Pesticides, fertilizers, and power lines have been researched for a direct link to childhood cancers. There has been evidence of cancer occurring among nonrelated children in certain neighborhoods and/or cities. Whether prenatal or infant exposure to these agents causes cancer, or whether it is a coincidence, is unknown.
- Some forms of high-dose chemotherapy and radiation. In some cases, children who have been exposed to these agents may develop a second malignancy later in life. These strong anticancer agents can alter cells and/or the immune system. A second malignancy is a cancer that appears as a result from treatment of a different cancer.