Investigation of the prognostic importance of long non coding RNA MALAT1 in primary glioblastoma tumors

The lncRNA (Long-noncoding RNA) MALAT1 (Metastasis associated in lung adenocarcinoma transcript 1) gene which is located on the chromosome 11 and it is known to be involved in the modulation of various molecular signaling pathways, influencing cell migration, cell invasion, immunity, angiogenesis and tumorigenicity. It is also associated with pathological features such as tumor location, size, differentiation, and cancer staging. In addition, increased evidences illustrate that abnormal expression of MALAT1 in tumor tissues or body fluids can be used as a biomarker for tumor diagnosis and prognosis. Overexpression of MALAT1 (which acts as an oncogene) in the glioma have been reported to be positively correlated with the degree and size of the tumor. However, the importance of MALAT1 especially in homogeneous primary Glioblastoma (GB) patients, prognosis remains uncertain. Based on available evidence for abnormal expression of MALAT 1, we have assumed that the irregularity of MALAT 1 may play a critical role in the pathogenesis of primary GB. The current lack of information in this field, is due to the hard task of evaluating the genetics mechanism of LncRNAs ( MALAT1 ) in GB. Therefore, in this thesis we aimed to analyze MALAT1 expression profiles in the IDH-wild type primary GB population. We demonstrate that MALAT1 expression was significantly upregulated and associated with short overall survival in IDH wild type primary GBs. In our study high levels of MALAT1 expression were associated with a young age group, with the GB being localized in the left hemisphere, more precisely in the insular lobe when compared with others cohorts. As a result, the mechanism of pathogenesis in primary GB is not yet fully understood and no treatment is available. Therefore, it is important to identify new molecular biomarkers and therapeutic targets for this devastating disease. In our study, based on multivariate COX regression analysis, high MALAT1 expression level were proven to be an independent poor prognostic factor for primary GB patients without IDH mutations. Also the release of MALAT1 plays as an independent prognostic parameter for survival within multiple cancers, including primary GB, where it will serve as a prognostic marker and therapeutic target.