Abstract BACKGROUND Ependymomas are heterogenous group of tumours with variable clinical course and diverse molecular features. RELA fusion status has been reported to have prognostic impact in ST-EPEN. Our retrospective… Click to show full abstract
Abstract BACKGROUND Ependymomas are heterogenous group of tumours with variable clinical course and diverse molecular features. RELA fusion status has been reported to have prognostic impact in ST-EPEN. Our retrospective study analysed the prevalence and clinical impact of RELA fusion in childhood ST-EPEN at our centre. STUDY METHODS FFPE tissues of all childhood ST-EPEN diagnosed during 2011–2017 were evaluated for RELA fusion 1/2 by RT-PCR. Children were treated as per guidelines by the Neuro-oncology multidisciplinary team. Outcomes were correlated with RELA fusion, histological features and immunohistochemical parameters(L1CAM expression and Mib-1 index). Only patients with therapy details were included. RESULTS A total of 37 patients(0–50 years) with ST-EPEN were included(median age-10.2 years; boy:girl ratio-1.4:1)for analysis. Histological grade II, II/III and III was seen in 4(11%),2(5%) and 31(84%) patients respectively. Mib-1 index was assessable in 33 patients of which, 9 patients (24%) had a Mib-1 index >20%. RELA fusion was detected in 13(35%)tumors. The 3-year and 5-year EFS/OS of the overall cohort was 64.2%/83.6% and 60.1%/73.1% respectively. The 3-year/5-year EFS of RELA-positive tumors was inferior compared to RELA-negative tumours (53.8%/36% v/s 62.6%/53.6%; p=0.391). The 3-year/5-year EFS of tumors expressing L1CAM versus negative-expression was comparable (61.1%/55%v/s59.8%/47.9%;p=0.44). Presence of Mib-1>20% correlated with inferior survival (5-year EFS:81.1%vs22.2%; p<0.01). CONCLUSIONS ST-EPEN with RELA fusion had trend towards increased relapse/progression. High Mib-1 correlated with poor survival. RELA fusion status needs to be studied in a larger cohort prospectively to confirm its clinical impact.
               
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