Retrospective clinical and molecular determination of wnt and SHH subgroups in OUR medulloblastoma tumor cases

Medulloblastoma (MB) is the most widely seen malign brain tumor in childhood. In addition surgery, treatment for this tumor is radiotherapy and chemotherapy but there is no spesific chemotherapy for MBs. It is limited by theraphies which is used for other pediatric glial tumours. Recent researches showed that, all MB cases have not same property, have different subgroups in molecular level, shows different prognosis for different patients and divided into four groups such as Wingless (WNT), Sonic Hedgehog (SHH), Group 3 and Group 4. Generally, these group distinctions based on the biological subtypes of MBs can usually be made clinically. It is thought that clinically determined subgroups can be important for molecular identification and support, differentiate patient groups obviously, and determining the treatment protocols from this respect. In this thesis study, it was aimed to determine the WNT and SHH subtypes at the molecular level and to compare them clinically by examining the CTNNB1, AXIN, PTCH1, SMO, SUFU and GLI1 mRNA expression changes in MBs of Turkish population determined according to patient selection criteria. In this context, the clinical distinction between WNT and SHH groups are realized by considering the age, gender, survival time, location of the lesion and radiological features of the patients. Molecular separation was performed by real time PCR (RT-PCR) analysis of CTNNB1, AXIN, PTCH1, SMO, SUFU and GLI1 mRNA expression changes. As a result, it was determined that 17.8% of the cases were included in the WNT group and 22.2% in the SHH group. When comparing group differences based on clinical and molecular data, 72.7% matches were observed in the WNT group and 66.6% in the SHH group. This thesis will set the grounds for the tumors that are not included in the WNT and SHH groups to be divided into Group 3 and Group 4 in terms of the clinical, pathological and demographic characteristics and mRNA levels of the MYC, MYCN, GFLB1, OTX-2, KDM6A, SNCAIP genes.