There are no known causes for brain tumors. Some factors that are associated with increased susceptibility to Brain Tumors are: Neurofibromatosis Von Hippel-Lindau disease Li-Fraumeni syndrome Tuberculous sclerosis Immunocompromised/ Immunosuppressed (weak immune system) – People who have a weak immune system have a higher risk of developing brain tumors. This may also include people who have had an organ transplant or are immunocompromised due to any other reason.