Biomarkers of Glioma

According to the analysis of American Brain Tumor Association, the brain tumors are common with an incidence of 12.8 per 100,000 people. Glioma is the most common subgroup of brain tumors. It is a type of tumor that origins in the brain or spine. It is called a “glioma” because it arises from glial cells. According to the specific type of cells from which they originate, gliomas are categorized as glioblastoma (WHO grade IV), astrocytoma (WHO grades I–III), oligodendro -glioma (WHO grades II and III), and mixed glioma (WHO grades II and III) (McCarthy et al, 2011). It is reported that about 50% gliomas are glioblastomas, which are the most common and malignant phenotypic astrocytoma. They are most common in adults from ages 45-55, and affect more men than women. About 9% of brain tumors in childhood are glioblastomas. Gliomas are difficult to treat. Usually the prognosis for patients with high-grade gliomas (especially for glioblastomas) is very poor, which has a mean survival only from 10 to 12 months (Reddy, et al, 2008). It is found that about 10,000 Americans are diagnosed annually with malignant gliomas, about half of these patients are survival 1 year after diagnosis, and 25% after two years. The traditional approach to treat the glioma contains surgery, radidtion therapy and chemotherapy. Although with these treatments or combined approaches, the tumor will be suppressed at some means, the survival rate of the patients is still very low. Biomarker is a characteristic that is objectively measured as an indicator of normal biological processes, pathogenic processes or a pharmacological response to a therapeutic intervention (Atkinson et al., 2001; Marrer & Dieterle, 2007). And tumor/cancer biomarkers are involved in tumors which contain a wide variety of objects, including DNA, mRNA, secreted proteins, cell surface receptors, transcription factors, and metabolites, or processes such as apoptosis, angiogenesis or proliferation. The markers are produced either by the tumor itself or by other tissues or cells, in response to the presence of tumors or other associated irritation, like inflammation (Kulasingam & Diamandis, 2008). They can be found in the tumor tissues, tumor cell lines, secreted molecules and in the serum or other body fluid, and so on. The tumor/cancer biomarkers can help doctors to profile the cancer predisposition, state of cancerous development, early diagnosis, prognosis after tretment, and decide which drugs and at what does it might be most effective to the patients with tumors. They are also benefit to screen the targeted drug for the tumor treatment. Recent years, the tumor/cancer biomarkers have played important roles in the diagnosis, therapy and prognosis in tumors. For example, prostate-specific antigen (PSA), as a best-