Brain Cancer and Tumors Brain cancers happen when one type of cell transforms from its general characteristics. Once it gets transmuted, the cells grow and multiply in abnormal ways forming a cancerous growth of cell mass. The early symptoms includes severe headaches and drowsiness early in the morning, sudden convulsions with involuntary movements of a person's muscles, personality or memory changes, fatigue, nausea or vomiting and sleep problems. The main causes for most brain cancer are unknown. Quiet genetic factors, strong dose of radiation to the head, environmental toxins and consumption of tobacco all of these have been linked to brain cancer .