Mehrdad Asghari Estiar1, Firouzeh Javan1, Ali Zekri2,3, Masoud Mehrazin4, Parvin Mehdipour1. 1. Department of Medical Genetics, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran. 2. Physiology Research Center, Iran University of Medical Sciences, Tehran, Iran. 3. Department of Medical Genetics and Molecular Biology, Iran University of Medical Sciences, Tehran, Iran. 4. Department of Neurosurgery, Shariati Hospital, Tehran University of Medical Sciences, Tehran, Iran.
Abstract
BACKGROUND: Astrocytoma and meningioma are the most common primary brain tumors. MYCN as a member of MYC proto-oncogenes has recently appeared as an attractive therapeutic target. Functions of MYCN are critical for growth of nervous system and neural differentiation. OBJECTIVE: We examined MYCN amplification and protein expression in astrocytoma and meningioma cases. METHODS: In this study, we used real-time PCR, FISH assay and flowcytometry to analyze DNA amplification and protein expression of MYCN. RESULTS: Among 30 samples of brain tumor, 14 cases (46.6%) revealed MYCN amplification. High-protein expression of MYCN was also observed in 43.3% of patients. There was a significant correlation between MYCN gene amplification and protein expression (r= 0.523; p= 0.003), interestingly five case showed discrepancy between the gene amplification and protein expression. Although MYCN amplification fails to show correlation with poor prognosis (p= 0.305), protein high-expression of MYCN significantly reduce disease-free survival (p= 0.019). CONCLUSIONS: Our results challenge the concept of the neural specificity of MYCN by demonstrating contribution of MYCN in meningioma. Moreover, this study highlights the importance of research at both level of DNA and protein, to determine the biological functions and medical impacts of MYCN.
BACKGROUND:Astrocytoma and meningioma are the most common primary brain tumors. MYCN as a member of MYC proto-oncogenes has recently appeared as an attractive therapeutic target. Functions of MYCN are critical for growth of nervous system and neural differentiation. OBJECTIVE: We examined MYCN amplification and protein expression in astrocytoma and meningioma cases. METHODS: In this study, we used real-time PCR, FISH assay and flowcytometry to analyze DNA amplification and protein expression of MYCN. RESULTS: Among 30 samples of brain tumor, 14 cases (46.6%) revealed MYCN amplification. High-protein expression of MYCN was also observed in 43.3% of patients. There was a significant correlation between MYCN gene amplification and protein expression (r= 0.523; p= 0.003), interestingly five case showed discrepancy between the gene amplification and protein expression. Although MYCN amplification fails to show correlation with poor prognosis (p= 0.305), protein high-expression of MYCN significantly reduce disease-free survival (p= 0.019). CONCLUSIONS: Our results challenge the concept of the neural specificity of MYCN by demonstrating contribution of MYCN in meningioma. Moreover, this study highlights the importance of research at both level of DNA and protein, to determine the biological functions and medical impacts of MYCN.