Glioblastoma multiformes (GBM) are the most common, as well as the most aggressive, form of cancerous brain tumors found in humans, according to MayoClinic.com. Treatment can be difficult and prognosis is often poor for people that suffer from this disease. Symptoms may include headaches, vomiting, seizures, and progressive neurological deficit such as memory issues or severe personality changes. However, the disease may be symptom-free during its early stages.
Viral Causes
Possible links between certain viral infections and the subsequent development of glioblastoma have been identified. These links include the Simian virus 40 (SV40) as well as cytomegalovirus. SV40 has been found in both monkeys and humans alike. It is a genetic virus that has the potential to form tumors in affected hosts---the virus gained some notoriety due to its detection in the injected form of polio vaccines in the late 1950s. Conversely, cytomegalovirus is a herpes-related virus that may present no symptoms in otherwise healthy individuals. In addition, a known relationship exists between malaria--a mosquito-borne infectious disease--and the occurrence of brain tumors. This evidence suggests that the carriers of malaria may transmit a sort of virus that can potentially lead to glioblastoma formation.
Group Risk Factors
According to a June 2005 study in the Journal of Neuropathology and Experimental Neurology, there appears to be a higher incidence of glioblastoma in the male population. Furthermore, individuals over 50 may also be at a higher risk, and Caucasians, Asians and Latinos comprise the top three ethnic groups commonly impacted by glioblastoma.
Genetic Factors/Disorders
Genetic defects and chromosome mutations may correspond to the development of glioblastoma. Changes to chromosomes may be related to environmental factors such as chemical exposure or radiation. Additionally, the presence of certain genetic disorders also correlates with increased incidences of the disease. These include tuberous sclerosis, a disease that causes tumors to develop within the brain and in additional vital organs of the body; neurofibromatosis, a disorder in which the body's nerve tissues can grow potentially harmful tumors; and Von-Hippel-Lindau disease, which leads to the growth of tumors in the central nervous system and the kidneys.
Existing Tumors
Individuals with pre-existing astrocytomas, which are otherwise benign, star-shaped tumors, are at risk of these growths developing into a higher-grade, cancerous glioblastoma. The precise cause of astrocytomas is not presently known.
References
- MayoClinic.com: Glioblastoma Multiforme
- Journal of Neuropathology and Experimental Neurology; "Population-based studies on incidence, survival rates, and genetic alterations in astrocytic and oligodendroglial gliomas"; Ohgaki H. and Kleihues P.; June 2005
- International RadioSurgery Association: Glioblastomas
