Because the brain controls all of the functions of the rest of the body, many of them are affected by brain cancer. When a tumor grows within the skull, it encroaches upon space needed by the brain. Symptoms can vary greatly from patient to patient and will also be determined by which part of the brain is affected by the cancer. Headaches could occur, as well as weakness in any of the extremities, in turn causing clumsiness or difficulty walking. Pain could occur in the stomach secondary to nausea and vomiting. Vision could be impaired as could the sense of smell. Seizures and mental/personality changes could also occur.