Brain cancer is a type of cancer that takes place in a brain and prevents it from functioning normally. It is characterized by the growth of cancer cells (either benign or malignant) in the brain tissue. The growth of these cells leads to the formation of tumor which affects the mental processes, brain and body functions. Malignant tumors are created by the growth of cancer cells; benign tumors are made by noncancerous cells. There is also one more differentiation, the one between primary brain tumors and metastatic brain tumors. Those cells that originate from brain tissue are considered the former. The latter are those that spread to the brain from other organs.

The condition of brain cancer is not so wide-spread as the ones of breast or prostate cancer but not less dangerous.  According to the data of National Cancer Institute (NCI) it has a tendency to develop in about 22,000 new people per year; in many cases it actually leads to death.

The condition has several grades according to which its severity is estimated. It develops individually in every person and can have different extent of manifestation.

There are four main grades of brain cancer according to NCI:

• Grade I means that the brain tissue is benign and that the cells composing the tumor grow slowly and look almost normal.
• Grade II entails that the brain tissue is malignant and that the cells composing the tumor look less than normal.
• Grade III stands for the malignant brain tissue and estimates the cells as anaplastic (almost abnormal) and active in their spreading.
• Grade IV means a malignant tumor and that the cells are abnormal and grow exceedingly fast.

Moreover, primary brain tumors bear the names of the tissues they originate from. The examples are: gliomas, meningiomas, pituitary adenomas, vestibular schwannomas, and medulloblastomas. These names (together with the number of the grade) make it easier for doctors to estimate the severity of the condition. Though there are malignant and benign tumors it does not mean that the latter are safe. They as well are dangerous and can cause troubles especially in case they grow too large and interfere with normal body functioning.