| GBM(glioblastoma multiforme) is the most frequent and malignant primary CNS tumor in adults. This fatal disease presents some of the greatest challenges in the management of cancer patients worldwide, despite notable recent achievements in oncology. Even with standard treatment, maximal safe surgical resections of tumor followed by irradiation and temozolomide adjuvant chemotherapy, the prognosis for GBM patients remains dismal: median survival after diagnosis is about 14 months. Not all patients can be benefited from the same effect after similar treatment. Established predictive factors are limited but include young age, high Karnofsky Performance status(KPS), mini-mental status examination score, restriction of >98% of the tumor and methylation of MGMT promoter. Although recent molecular and genetic profiling studies have identified several markers and unique signatures as prognostic and predictive factors of GBM, these results presents some of disadvantages.MicroRNAs(miRNA) are an abundant class of small, non-protein-coding RNAs that are believed to posttranscriptionly regulate gene expression negatively. Abbrrent expression of miRNAs is associated with diverse diseases, specially with cancers. Because a single miRNA can regulate hundreds of downstream genes with different biologic entities, the information gained from miRNA profiling may provide more accurate classification of cancer subtypes than the use of expression profiles of protein-coding genes. Many studies identifying mi RNA expression signatures, derived from GBM tissue, predicting patient survival have been done in several studies. Rencntly we discovered with excitement the human serum/plasma contains a large amount of stable miRNAs and that unique expression patterns of serum miRNA profiling as the fingerprint for disease, due to easy acquisition it is. Consitently, others studies identifying miRNA expression signatures predicting patient survival have been done in several cancers like NSCLC. However, a serum miRNA signatures that can predict the clinical outcome in GBM patients has not been found so far.In this study, we hypothesize that there is a serum miRNA profile that can be identified as a fingerprint to predict clinical outcome of GBM. To address this hypothesis, we screen serum mi RNAs by using Solexa sequencing followed by an extensively self-validated study that use individual quantitative RT-PCR(qRT-PCR) assays. Finally, SPSS 19.0 Software was used to confirm whether the results were statistically signifcant.First, we collected and kept plasma of GBM before any treatment from Beijing Tiantan Hospital, tracked their survival and made records. The total number is 127. Then we divided these samples into two parts according to the median survival(393 days). Subsequently, Solexa Sequencing technology was used to identify the different expression level of miRNAs between the two groups. The results showed that there was total 63 miRNAs expressed differently. Second, we selected 16 miRNAs to be tested by qRT-PCR method, which had much possibility to associate with GBM prognosis according to reported literature and conclusion of our lab. In this stage, two miRNAs(miR-27 b, miR-148b) were screened out to be up to the standard that the expression level difference is over 2 fold and the discrimination is significant statistically(T-test, P<0.05). Finally, for each miRNA, we constructed the ROC curve and calculated the area under the ROC curve(AUC) to evaluate the specificity and sensitivity of GBM survival prediction. The AUC of miR-27 b is 0.872,while miR-148 b is 0.818. The associations between overall survival and serum mi RNA expression levels were estimated by using the Kaplan-Meier method, and Log-Rank test(P<0.0001). Cox proportional hazard regression models was used to validate whether the two miRNAs was independent of age and gender. The results showed that the two miRNAs are related to the survival of GBM patients negatively but without age and gender. |
PDF Full Text Request