Abstract
IDH mutation, MGMT methylation and Neurotrophic Tyrosine Receptor Kinase (NTRK) rearrangement have all been detected in different types of CNS tumours. The Pan-Trk protein plays an important role in the neuronal development and cellular growth. Our aim was to explore if Pan-Trk expression in tumour microenvironment is related to IDH mutation and MGMT methylation. This study included twenty-three patients diagnosed with different types of CNS tumours. Testing for Pan-Trk and IDH1 was performed on all FFPE tissues. This assessment has been correlated with MGMT methylation and NTRK rearrangement. The mean age of all cases was 36 years; 19 tumours were glial, and the remaining 4 cases were non-glial. IDH-mutation was identified in 5 tumours ( 21.7%) and the remaining cases were IDH-wildtype (78.3%). MGMTpromoter was methylated in 4 cases (17.4%) and 19 cases (91.3%) showed unmethylated MGMT. Pan-Trk was expressed in 11 tumours (47.8%) and the rest (52.2%) showed no Pan-Trk expression. There was no statistically significant association between Pan-Trk expression, IDH-mutation and MGMT methylation (p>0.05). There was also no statistically significant relationship between these three biomarkers with recurrence-free interval (RFI). The late recurrence was only observed among tumours having expressed PanTrk, IDH-mutation and unmethylated MGMT (Median =20.32 months). About 60% of cases who received chemotherapy have showed longer RFI however, no significant association was observed (p= 0.567). Pan-Trk should not be used as a screener to detect NTRKrearrangement in CNS tumours but can be considered as a signalling biomarker to understand the relationship between IDH- mutation and MGMT-promoter methylation in tumours microenvironment.