**Critical Molecular and Genetic Markers in Primary Brain Tumors with Their Clinical Importance**

Ilhan Yaylim, Sumeyya Azam, Ammad Ahmad Farooqi, Özlem Küçükhüseyin, Muhammad Ismail and Ali Metin Kafadar

Additional information is available at the end of the chapter

http://dx.doi.org/10.5772/63550

#### **Abstract**

Classification of primary brain tumors is based mainly on histopathological character‐ istics. Due to the peculiarity of the central nervous system (CNS), the location of the tumor is also used in the naming of the CNS tumors. These features, histopathology, and location determine the main prognostic factors in these tumors. Updated molecu‐ lar and genetic findings in the last two decades accumulated vast amount of knowl‐ edge about the biological behavior, response to the treatment, and consequently the prognosis of CNS tumors. After the clinical use of these data, a recent classification is proposed by the International Society of Neuropathology named as "integrated diagnosis."

This classification considers the histopathological classification, World Health Organization (WHO) grade along with the molecular information. The emerging molecular-genetic data about the CNS tumors will allow the translational researchers to deliberately understand the oncogenic mechanisms involved in the evolution of these tumors and judge the optional treatment strategies.

Evaluating the check points of cell cycle and apoptosis provides valuable information about the tumor biology (tumorigenesis). These mechanisms (pathways) also play an exclusive role in CNS tumors. Knowledge concerning the gene repressors and gene activators or some epigenetic changes in proliferative and antiproliferative pathways that regarded gliomas may yield new individualized treatment options.

In this chapter, we will review the basic and translational research molecular-genetic data of gliomas with special interest on proliferative and antiproliferative pathways. Further emerging treatment options and treatment responses in gliomas will be

© 2016 The Author(s). Licensee InTech. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

critically evaluated with regard to their histopathology, anatomical location, and molecular-genetic fingerprints.

**Keywords:** gliomas, proliferation, apoptosis, cell cycle, gene
