Rasime Kalkan

IDH1 mutations is prognostic marker for primary glioblastoma multiforme but MGMT hypermethylation is not prognostic for primary glioblastoma multiforme

PURPOSE To establish the frequency of IDH1 mutations and MGMT methylation in primary glioblastomas. EXPERIMENTAL DESIGN We screened primary glioblastoma multiforme (GBM) in a population-based study for IDH1 mutations and MGMT methylation and correlated them with clinical data. RESULTS IDH1 mutations were detected in 5 of 40 primary glioblastomas (12,5%). Primary GBM patients carrying IDH1 mutations were significantly younger, mean age of 41±5.06years, than patients with wild-type IDH1, mean age of 57±2,29years, p=0.011. The mean survival time of all GBM patients with and without IDH1 mutations was 19months (5 cases) and 16months (35 cases), respectively (p>0,05). MGMT methylation was detected in 13 of the 40 patients (32,5%). MGMT-promoter methylation did not correlate with overall survival (OS; p>0,05). CONCLUSION In summary, our study is the first study to investigate the IDH1 mutation status and MGMT methylation in primary GBMs in Turkish population and confirmed IDH1 mutation as a genetic marker for also primary GBMs. Our data are still insufficient for definite ascertainment; and our preliminary results suggest: IDH1 status shows an association with younger age and there is a lack of association between IDH1 mutation and survival time. Furthermore MGMT promoter methylation had no prognostic value and lower frequency in primary glioblastomas.

A unique mosaic Turner syndrome patient with androgen receptor gene derived marker chromosome.

Abstract Patients with Turner syndrome are generally characterized by having short stature with no secondary sexual characteristics. Some abnormalities, such as webbed neck, renal malformations (>50%) and cardiac defects (10%) are less common. The intelligence of these patients is considered normal. Non-mosaic monosomy X is observed in approximately 45% of postnatal patients with Turner syndrome and the rest of the patients have structural abnormalities or mosaicism involving 46,X,i(Xq), 45,X/46,XX, 45,X and other variants. The phenotype of 45,X/46,X,+mar individuals varies by the genetic continent and degree of the mosaicism. The gene content of the marker chromosome is the most important when correlating the phenotype with the genotype. Here we present an 11-year-old female who was referred for evaluation of her short stature and learning disabilities. Conventional cytogenetic investigation showed a mosaic 45,X/46,X,+mar karyotype. Fluorescence in situ hybridization showed that the marker chromosome originated from the X chromosome within the androgen receptor (AR) and X-inactive specific transcript (XIST) genes. Therefore, it is possible that aberrant activation of the marker chromosome, compromising the AR and XIST genes, may modify the Turner syndrome phenotype.

Role of Mesenchymal Stem Cells in Cancer Development and Their Use in Cancer Therapy

Stem cells have the ability to perpetuate themselves through self-renewal and generate mature cells of a particular tissue through differentiation. Mesenchymal stem cells (MSCs) play an important role in tissue homeostasis - supporting tissue regeneration. MSCs are rare pluripotent cells supporting hematopoietic and mesenchymal cell lineages. MSCs have a great therapeutic potential in cancer therapy, as well as stem cell exosome and/or microvesicle-mediated tissue regeneration. In this review, the use of hMSCs in stem cell-mediated cancer therapy is discussed.

Double faced role of human mesenchymal stem cells and their role challenges in cancer therapy.

Human mesenchymal stem cells (hMSCs) are multipotent non-hematopoietic precursor cells with the ability to differentiate into several tissue types. The use of hMSCs has gained significant importance in cancer therapies as well as a large number of degenerative disease therapies due to their homing abilities. However, these cells may undergo spontaneous transformation leading to them bypassing naturally built-in cell controls that could lead to senescence and carcinogenesis. Therefore, although MSCs have great potential for cancer therapy, they also risk the development of cancer, which provides them with double-faced characteristics for both cancer development and therapy. The potential use of hMSCs in therapeutics from the aspect of in vitro expansion of hMSCs and telomere dynamic is discussed.

The Impacts of miRNAs in Glioblastoma Progression.

miRNAs are short noncoding RNA sequences that cause translational repression or mRNA degradation. A growing number of studies have sought new biomarkers in GBM that will be important in disease progression and prognosis and as potential therapeutic targets. miRNA-profiling studies in glioblastoma patients have found that aberrant miRNA expression can be used as a target to develop new biomarkers for disease detection and for determining prognosis or therapeutic response. In evaluating the tumor or its therapeutic response, genetic abnormalities such as mutations, epigenetic abnormalities, and aberrant miRNA expressions can be useful markers. This review summarizes the known miRNAs according their therapeutic importance and their use as disease progression biomarkers.

Human Mesenchymal Stem Cells in Cancer Therapy.

Human mesenchymal stem cells (hMSCs) have the ability to differentiate into several tissue types. Their use in cancer therapeutics or as therapeutic delivery vehicles has significant potential, particularly in their exosome/microvesicle-mediated tissue regeneration abilities. In this review, the potential use of hMSCs in cancer therapy is discussed.

RARβ gene methylation is a candidate for primary glioblastoma treatment planning

BACKGROUND We screened RARβ methylation in primary glioblastoma multiforme (GBM) and the results were evaluated based on the clinical data and treatment type. OBJECTIVE The objective of this study was to find new areas for the usage of MS-HRM applications in the determination of methylation levels in primary GBM samples and it shows the association of RARβ methylation with the clinical outcome. METHODS In our study, tumor samples were collected during surgical resection by the Department of Neurosurgery. The clinical and radiologic data was carefully reviewed, compared, and evaluated with the histological results. The methylation status of RARβ was determined by using MS-HRM. RESULTS RARβ gene methylation was detected in 24 out of 40 cases (60%), with different quantitative methylation levels. The mean survival time was 19 months form ethylated cases and 15 months for the non-methylated cases. The survival time of the patients who received treatment was 25 months and the survival time of the patients who received radiotherapy alone or where no treatment protocol applied was 15-20 months. Therefore, a significant difference in survival rates has been observed (P<0.05). This study indicates a potential prognostic value for GBM treatment planning. CONCLUSION Our study is the first study to investigate RARβ methylation in primary GBMs. We conclude that the RARβ gene could be a new prognostic and predictive candidate marker to designate the treatment protocol for primary GBMs.

Receptor tyrosine kinase-Ras-PI 3 kinase-Akt signaling network in glioblastoma multiforme

Glioblastoma multiforme (GBM) is the most malignant form of the brain tumors and shows different genetic and epigenetic abnormalities. Gene amplification, genetic instability, disruption of apoptotic pathways, deregulated oncogene expression, invasive phenotypical changes, abnormal angiogenesis, and epigenetic changes have all been described in GBMs. These abnormalities indicate that a number of different signaling pathways are deregulated in GBM. Increasing number of studies provide a better understanding of the tumor biology, genetic, and epigenetic background of the GBM. Also, current research provides us useful approaches in designing novel therapies for GBM. In this review, we summarize the receptor tyrosine kinase-Ras-PI 3 kinase-Akt signaling network, focusing on the potential molecular targets for anti-signaling molecular therapies in this pathway.

The Importance of Mutational Drivers in GBM.

Glioblastoma (GBM) is the most aggressive primary brain tumor, providing few effective therapeutic options, given the tumor heterogeneity and the accumulation of different genetic abnormalities that cause treatment failure. The many different genetic and epigenetic alterations present in GBM lead to modification of several major signaling pathways resulting in brain tumor growth, progression, and therapeutic resistance. Many functionally important mutations have been discovered, known as neutral passengers. IDH1/2, EZH2, and DNMT3A are the best known epigenetic modifiers in cancer. These mutations are important in determining disease prognosis such that the status of the MGMT gene is a direct target of chemotherapy. For these reasons, newly developed technologies are necessary to determine new candidate targets for targeted-therapy development in GBM. The determination of mutations will aid in this and in the discovery of combinations of targeted and conventional therapies to improve GBM treatment.