What Causes It Most brain tumors have no known cause. The field of molecular genetics is devoted to understanding the changes that occur in cells that allow them to acquire malignant characteristics and form tumors. Although many of these cell alterations have been identified, the process of how these changes lead to the development of tumors is not yet well understood.
A variety of statistical and environmental associations have been made, but no chemical or environmental agent has been definitely shown to cause brain tumors.
Some inherited conditions predispose a person to the development of brain tumors. Patients with neurofibromatosis, tuberous sclerosis and familial polyposis have a tendency to develop astrocytomas.
Viruses are known to produce genetic changes in cells that in laboratory animals can induce the formation of a tumor. There is an association in people infected with the Epstein-Barr virus and primary central nervous system lymphoma, although a definite causal relationship remains to be established. Central nervous system lymphoma frequently develops in immunosuppressed patients, such as those who have received an organ transplant or those who have AIDS.
Radiation can produce genetic damage in cells and induce tumors. It was once standard medical practice to use low doses of radiation to treat ringworm of the scalp in children. Years later it was found that children treated this way had an increased chance of developing tumors of the scalp, skull and brain. These radiation-induced tumors have a much greater likelihood of being malignant than do the forms that occur spontaneously.
