Brain tumors types First group of categorizing brain tumors should be based on their character: benign or malignant. Benign tumors don?t have cancerous cells and they cannot metastasize. Malignant tumors in the brain consist of cancer cells which are not limited to the original tissue and can spread to the neighboring areas and metastasize. It is possible to classify brain tumors as primary and secondary. The thing is that primary tumors originate in the brain cells. They might be of both types cancerous or not. And secondary tumours represent metastasized cells which have spread from some body part to the brain and they are definitely cancerous. Causes of brain cancer Actually the exact causes of brain cancer are not revealed yet and the reasons are still ambiguous. However it is obvious that brain cancer is not contagious and an individual cannot catch it from a person with a tumor. Although the definite cause eludes us, there are risk factors which might increase the risk of developing a cancerous tumor. In fact, gender is the main risk factor. Brain cancer is detected predominantly in men. Age is also a risk factor. Actually tumor develops most often in people who are in their 60s and above. However kids under 8 years old are also prone to developing this disease. Among other risk factors we can name exposure to radiation and family history. Basically it develops because of certain abnormalities in genes which are responsible for regulating the cycle of cell growth leading to uncontrolled growth and division of cells. The genes abnormalities could happen because of specific rearrangements of the chromosome or alterations in genes themselves. The abnormalities often result from a cascade of events which occurs at biological and molecular levels. Several genetic conditions, including neurofibromatosis, retinoblastoma, Li-Fraumeni syndrome, etc. can trigger the risks of cancer in the central nervous system. In fact, genetic abnormalities that provoke brain tumors are not usually inherited. Mainly they are caused by different environmental conditions and some factors which affect DNA and other genetic materials. There are many chemicals which may alter genes responsible for restraining the tumor development. Employees working in oil refineries, rubber manufacturing factories, or those who work as chemists are exposed to harmful and dangerous chemicals. The people who have been treated by some type of radiation for managing some malignant tumors are also at high risk of developing brain cancer.