EPEN-19. SUPRATENTORIAL EPENDYMOMAS - L1CAM EXPRESSION AND RELA FUSION, THEIR CORRELATION WITH CLINICOPATHOLOGICAL FEATURES

• Published in: Neuro-oncology (Charlottesville, Va.) Va.), 2018-06, Vol.20 (suppl_2), p.i77-i77
• Main Authors: Anvekar, Gouri, Gurav, Mamta, Shetty, Omshree, Kadam, Vinayak, Sahay, Ayushi, Chinnaswamy, Girish, Shetty, Prakash, Moiyadi, Aliasgar, Gupta, Tejpal, Jalali, Rakesh, Epari, Sridhar
• Format: Article
• Language: English
• Subjects: Abstracts
• ISSN: 1522-8517; 1523-5866
• DOI: 10.1093/neuonc/noy059.220

Abstract INTRODUCTION This study was undertaken to evaluate the frequency of RELA fusion 1/2 in supratentorial ependymomas and its L1CAM and cylin D1 expression. MATERIALS AND METHODS Evaluated for histological features, immunohistochemical parameters (p53 protein, cyclin D1 and L1CAM expression) and rt-PCR for RELA fusion 1/2. The clinical parameters of these cases were also noted. RESULTS Total 71 cases; age range: 1-76yrs (interquartile range: 6-24yrs). Male (n=46): female (n=25) ratio 1.8: 1. Intraparenchymal-58 (commonly parietal), ventricular-13. Histological subtypes were subependymoma (grade I, n=4), ependymoma (grade II, n=8), anaplastic ependymoma (grade III, n=54) and ependymoma with atypical features (intermediate between grade II and III, n=5). 64.7% (44/68) showed p53 protein over-expression, 79.7% (55/69) cyclin D1 over-expression and 57.7% (41/71) L1CAM positivity. RELA fusion 1/2 positivity was detected in 45% of the cases (27/60; 22 Type 1, 5 Type 2). 63.2% (24/38) were ≤14 years (0-3yrs: 5/8, 4-9yrs: 12/17, 10-14yrs: 7/13). All RELA fusion-positive cases showed p53 protein, cyclin D1 and L1CAM over-expression while none of the cyclin D1 or L1CAM negative cases showed RELA fusion. With RELA fusion by rt-PCR as the reference test, L1CAM IHC showed 100% sensitivity, 59.4% specificity, 66.7% PPV and 100% NPV. CONCLUSIONS RELA fusions 1/2 are common in younger age (≤ 14yrs) and identified across all histological subtypes except subependymoma. All L1CAM and cyclin D1 negative cases were also negative for RELA fusion, thus combined L1CAM and cyclin D1 negativity can be used as predictive maker for RELA fusion negativity.