The Role of Matrix Metalloproteinases a nd Tissue Inhibitors of Metalloproteinases in the Progression of Astrocytomas

Abstract

Neoplasms of the central nervous system (CNS) constitute a group of tumors that are heterogeneous in epidemiology, biological behavior, genetic alterations, histological type, tumor location, pattern of spread, clinical presentation, natural history, age of occurrence, and prognosis (Behin et al., 2003; Louis, 2006; Stroher et al., 2000). According to the 2010 Surveillance Epidemiology and End Results [SEER] data, there were approximately 22,020 deaths from cancers of the brain and nervous system in the U.S. As reported by Binder et al., (2003) and Wrensch et al., (2002), some 7 to 16 cases of primary CNS tumors per 100,000 person-years are diagnosed in adults; approximately 50% of these cases are metastatic tumors, according to Hill et al. 1999. CNS tumors are the third leading cause of cancer deaths in middle-aged adults, the second most common cause of death in children, and the most common solid tumor in children (Giles, 1995; Heuer et al., 2007). The incidence of CNS tumors in children and adolescents is approximately 2.7 cases per 100,000 patients per year. This figure accounts for 16% of the neoplasms within this group, making CNS tumors the second most frequent type of cancer (after leukemia) in young patients (20 years old and younger). The mortality rate observed with CNS tumors is one of the highest among childhood cancers. Diagnosis and treatment improvements, however, has contributed to the survival of these patients (Potter et al., 1998). Epidemiological studies have shown a slight increase in the incidence of CNS tumors during the 1980s and 1990s in children and the elderly (Fisher et al. 2007; Swensen & Bushouse 1998). The apparent increase in the number of cases of CNS cancers is directly linked to the implementation of high-resolution neuroimaging tools, such as Magnetic Resonance Imaging (MRI) and Computed Tomography (CT), which have impacted the clinical diagnosis of neurological diseases (Cristensen et al., 2003; Fisher et al., 2007). Another