Topics and Speakers Jeffrey N. Bruce, MD
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Synopsis
Brain tumors are the second leading cause of cancer among children. The most common brain tumor, glioblastoma, is highly malignant, with few patients surviving beyond one year. Dr Jeffrey N. Bruce divides his lecture on brain tumors into three main sections. First, he provides a clinical overview of brain tumors. He then describes how brain tumors are classified by clarifying the often confusing nomenclature involved. Finally, Dr Bruce discusses the molecular biology of brain tumors and shows how research into molecular biology might yield effective treatment options.
What causes gliomas? Unfortunately, Dr Bruce notes, no clear correlation exists between any factor and the development of gliomas. Dr Bruce distinguishes between primary brain tumors, which begin in the brain, and secondary brain tumors, which are metastatic tumors that migrate to the brain from elsewhere in the body. This lecture focuses on primary brain tumors, such as gliomas, glioblastomas, astrocytomas, and meduloblastomas.
The location of the tumor is critical to the outcome. As Dr Bruce points out, any tumor that irritates the cortex may cause seizures. Similarly, a tumor located in the speech and motor areas of the dominant hemisphere would render speech impossible. Other tumors increase intracranial pressure, which can lead to headaches, nausea, and vomiting.
All gliomas, whether low or high grade, are highly invasive, making them difficult to treat. Although the tumor may appear circumscribed, malignant cells often spread and invade surrounding brain tissue. Angiogenesis is a prominent feature of these tumors and correlates with the time to recurrence, progression, and death.
Focusing on a cellular point of view, Dr Bruce explains how these tumors start. There is enormous plasticity in the adult brain, as evidenced by the presence of stem cells and progenitor cells. These cells indicate the brain's ability to regenerate both protectively and pathologically, with some regeneration evolving into an astrocytoma or some other type of tumor.
Dr Bruce then moves to the characteristics of primary brain tumors and their molecular biology. He starts with a review of the often confusing nomenclature and grading for brain tumors and then provides examples of different types of tumors and where they originate. The focus then shifts to the genes involved in regulating of these tumors, such as oncogenes, growth factor genes, and tumor suppressor genes. Accurate classification of tumors requires an understanding of the molecular changes present in different types of tumors. Diagnosing the particular tumor present is crucial since different tumor types respond differently to specific therapies. Dr Bruce ends the lecture with a review of current and emerging therapies for brain tumors, such as highly directed treatments, immunotherapy, and vaccines.
