Immunohistochemical Expression of Nestin as Cancer Stem Cell marker in Gliomas

Background: Gliomas represent the most frequent primary tumors of central nervous system (CNS), contributing to more than half of the incidence of brain tumors. Cancer stem cell markers (CSC) identify a group of patients at high risk for progression. Nestin is an intermediate fi lament (IF) protein was fi rst described as a neural stem cell/progenitor cell marker. Nestin-positive neuroepithelial stem cells are detected in the subventricular zone of the human adult brain and they remain mitotically active throughout adulthood. The expression of Nestin in gliomas has been suggested to be related to dedifferentiation, improved cell motility, invasive potential and increased malignancy. This study aims to investigate Nestin immunohistochemical expression in different types of glioma and its correlation with different clinicopathological parameters. Materials and Methods: Nestin immunostaining was studied in 60 specimens of glioma using avidinbiotin peroxidase method. Results: Nestin was strongly expressed in 11/60 (18.33%), moderately expressed in 29/60 (48.33%) and weekly expressed in 15/60 (25%) of studied gliomas. A signifi cant positive correlation was found between Nestin expression and histologic type (p< 0.001) and increasing grade of gliomas (p< 0.001). Conclusion: Increased Nestin expression is correlated with tumor progression, increasing grade, and poor prognostic parameter of glioma. Nestin is a useful marker for detection of CSC in high-grade glioma which is responsible for resistance to chemo-radiotherapy and may serve as a predictor for patient outcomes. Research Article Immunohistochemical Expression of Nestin as Cancer Stem Cell marker in Gliomas Rasha Mokhtar Abdelkareem1*, Afaf T Elnashar1, Khaled Nasser Fadle2 and Eman MS Muhammad1 1Department of Pathology, Sohag University, Egypt 2Department of Neurosurgery, Sohag University, Egypt Received: 18 October, 2019 Accepted: 30 October, 2019 Published: 31 October, 2019 *Corresponding author: Rasha Mokhtar Abdelkareem, Department of Pathology, Sohag University, Egypt, E-mail:


Introduction
Gliomas are the most common brain tumors, contributing to more than half of the incidence of brain tumors [1]. They comprise a heterogeneous group of neuroectodermal tumors that arise from the glia cells that may give rise to astrocytomas, oligodendrogliomas, and ependymomas, respectively. In recent years, advances in the understanding of low-grade glioma (LGG) biology have driven new paradigms in molecular markers, diagnostic imaging, operative techniques and technologies, and adjuvant therapies. Taken together, these developments are collectively pushing the envelope toward improved quality of life and survival [2].
Gliomas are responsible for approximately 13,000 cancer-related deaths in the United States each year [3]. In Egypt, CNS neoplasms represent 1-2% of all human neoplasms with high grade gliomas being the most common types [4].
Glioma develops through dedifferentiation of cells constituting the mature brain. However, a series of studies has reported the close involvement of Cancer stem cells (CSCs) in the mechanism of the development of glioma [5].
The search for prognostic and predictive biomarkers in gliomas is an area of considerable interest because patients respond differently to treatment and have different prognosis [6]. Some researchers suggest that tumor biology and resistance to treatment are closely connected to the existence of CSCs [7].
The importance of CSCs for estimating the prognosis of patients with glioma has therefore been widely investigated using several markers closely related to the presence of these cells [8]. The CSCs are responsible for resistance of glioblastomas multiform (GBM) to radiotherapy and chemotherapy, thereby contributing to poor survival of these patients [9].
The importance of CSCs in estimating the prognosis of patients with gliomas has therefore been widely investigated using several markers closely related to the presence of these cells [10].
Nestin is a class VI intermediate fi lament (IF) protein that was fi rst described as a neural stem/progenitor cell marker [11]. Neuroepithelial stem cells can differentiate into neurons, oligodendrocytes, and astrocytes, and Nestin has been shown to be down-regulated completely disappeared during such differentiation [12]. An investigation of Nestin as a cell surface marker of CSCs showed that the effi ciency of diagnosis and treatment of brain malignancies can be ameliorated by determining these cell surface markers [13].

Tissue samples
Formalin-fi xed, paraffi n-embedded brain tumor tissue blocks from sixty patients were selected prospectively from specimens that were delivered to Pathology Laboratory from Neurosurgery Department, Faculty of Medicine, Sohag University during the period from January 2016 to July 2018.
The research was approved from the ethical committee.
Gliomas were graded in accordance with the WHO, 2016 grading system, based on specifi c histopathological characteristics such as cellularity, nuclear atypia, mitotic activity, microvascular proliferation and necrosis.

Immunohistochemistry
After evaluating Hematoxylin and Eosin stained slides, serial sections from each block were used for Immunohistochemistry (IHC) of Nestin using avidin biotin peroxidase complex method. A dilution of 1:150 from Mouse monoclonal antibody against human Nestin (Clone 10C2, Cat. # GTX30671, Gene Tex) was used.

Statistical analysis
Data was analyzed using SPSS program version 17.0.
Quantitative data was expressed as means ± standard deviation, median and range. Qualitative data was expressed as number and percentage. The data were tested for normality using Shapiro-Wilk test. The nonparametric Mann-Whitney test, Kruskal-Wallis test and Spearman's correlation w ere used for data which wasn't normally distributed. P value <0.05 was considered statistically signifi cant and < 0.001 was considered highly signifi cant.

Conclusion
Increased Nestin expression is correlated with tumor progression, increasing grade, and poor prognosis of glioma.
Nestin is a useful marker for detection of CSC in high-grade glioma and may serve as a predictor for patient outcomes.

Recommendations
Studying the expression of Nestin on a large number of cases, different varieties of gliomas and on surgical resection margins.
Prospective studies properly powered based on this study should be undertaken to determine the signifi cance of these fi ndings; follow up of patients and getting enough information about response to treatment to emphasize the correlation between Nestin expression and the patient overall survival and disease outcome.
Studying the change in expression of Nestin in correlation with other CSC markers (e.g CD133) to clarify their role in glioma tumorigenesis.