TURKISH JOURNAL OF ONCOLOGY 2019 , Vol 34 , Num 4
Mutational Screening of miR-17-92 Cluster and miR-34a by DNA Sequencing in Childhood High-Grade Brain Tumors
Avni SARAÇ2,Ferda ALPASLAN PINARLI1,Faruk Güçlü PINARLI2,Aylar POYRAZ3,Aynur OĞUZ2,Ceyda KARADENİZ2,Arzu OKUR2,Kemali BAYKANER4,Abdullah EKMEKÇİ5,İrem DOĞAN5
1Dışkapı Yıldırım Beyazıt Training and Research Hospital, Genetic Diagnosis Center, Ankara-Turkey
2Department of Pediatric Oncology, Gazi University Faculty of Medicine, Ankara-Turkey
3Department of Surgical Medical Sciences, Medical Pathology, Gazi University Faculty of Medicine, Ankara-Turkey
4Department of Surgical Medical Sciences, Neurosurgery, Gazi University Faculty of Medicine, Ankara-Turkey
5Department of Medical Biology and Genetics, Gazi University Faculty of Medicine, Ankara-Turkey
DOI : 10.5505/tjo.2019.1812 OBJECTIVE
The miR-17-92 cluster and miR-34a are short non-coding RNAs, which are important in tumorigenesis as they regulate numerous oncogenes and tumor suppressor genes. This study aimed to investigate the associations of mutations/polymorphisms of the miR-17-92 cluster and miR-34a coding sequences with high-grade central nervous system malignancies in pediatric patients.

METHODS
This study included 53 children with central nervous system malignancies and age- and gender-matched 27 healthy volunteers. Genomic DNAs were extracted from the paraffin-embedded tumor tissues (n=53) and peripheral blood samples (n=15) in the patient group and from the peripheral blood samples in the control group and were analyzed for mutations/polymorphisms of the miR-17-92 cluster and miR-34a coding sequences by DNA sequencing method.

RESULTS
There were no copy number alterations, amplifications, deletions, insertions, duplications, rearrangements, single nucleotide polymorphisms or mutations in the miR-17-92 cluster and miR-34a coding sequences of tumor tissue or blood samples in the patient group and of blood samples in the control group.

CONCLUSION
In children with high-grade brain tumors, no mutation was detected, leading to failures in regulations of miRNA coding DNA sequences of miR-17-92 and miR-34a. Further studies are needed to elucidate extremely complicated mechanisms underlying oncogenesis in high-grade central nervous system tumors. Keywords : Cancer; central nervous system; miRNAs; oncogene; tumor