Glioblastoma multiform is the most common and lethal primary central nervous system tumor. Circulating microRNAs (miRNAs), present in cell-free bodily fluids, have been gaining importance as cancer biomarkers. The primary aim of this study was to assess whether circulating miRNA-128, -21, and -26a in glioblastoma patients can be used as diagnostic biomarkers. Venous blood samples were collected from 11 noncancerous volunteers and 15 glioblastoma patients preand post operation. Also, tissue tumor samples were obtained intra-operationally to assay consistency of miRNA levels in serum and tissue samples. Serum and tissue levels of miRNAs were determined by quantitative reverse transcription PCR. miR-21 and miR-26a were both significantly upregulated in pre-and postoperation serum samples of glioblastoma patients compared with the serum samples of noncancerous controls. We found that all three miR-128, -21, and -26a expression levels were reduced in postoperative serum samples compared with pre-operative serum samples, though this decrease was only significant for miR-26a. The serum miR-26a and miR-21 upregulation in glioblastoma patients compared to noncancerous controls and their downregulation in postoperative serum from glioblastoma patients suggest that these miRNAs could be used as serum-derived miRNA biomarkers for glioblastoma.

Over the latest decade, the role of microRNAs (miRNAs/miRs) has received more attention. miRNAs are small non-coding RNAs that may serve a role as oncogenes or tumor suppressor genes. Certain miRNAs regulate the apoptosis pathway by influencing pro- or anti-apoptotic genes. We hypothesized that increases in the expression of B cell lymphoma 2 () and BCL2-like 1 () genes, which have been reported in various types of cancer tissues, may be due to the downregulation of certain miRNAs. The present study aimed to identify miRNAs that target and anti-apoptotic genes in prostate cancer (PCa) clinical tissue samples. Certain candidate miRNAs were selected bioinformatically and their expression in PCa samples was analyzed and compared with that in benign prostatic hyperplasia (BPH) tissue samples. The candidate miRNAs that targeted and genes were searched in online databases (miRWalk, microRNA.org, miRDB and TargetScan). A total of 12 miRNAs that target the 3'-untranslated region of the aforementioned genes and/or for which downregulation of their expression has previously been reported in cancer tissues. A total of 30 tumor tissue samples from patients with PCa and 30 samples tissues from patients with BPH were obtained and were subjected to reverse transcription-quantitative polymerase chain reaction for expression analysis of 12 candidate miRNAs, and the and genes. Additionally, expression of 3 finally selected miRNAs and genes was evaluated in prostate cancer PC3 and DU145 cell lines and human umbilical vein endothelial cells. Among 12 miRNA candidates, the expression of miR-1266, miR-185 and miR-30c-2 was markedly downregulated in PCa tumor tissues and cell lines. Furthermore, downregulation of these miRNAs was associated with upregulation of the and genes. An inverse association between three miRNAs (miR-1266, miR-185 and miR-30c-2) and two anti-apoptotic genes ( and ) may be considered for interventional miRNA therapy of PCa.