P11.76.A SPECTRUM OF TP53 SOMATIC MUTATIONS IN A PROSPECTIVE STUDY OF PATIENTS WITH GLIOMA

Abstract

Abstract BACKGROUND TP53 mutations occur frequently in gliomas, being most common in IDH-wild-type (WT) glioblastomas (GB) and in IDH-mutant (MUT) oligodendrogliomas (OD). Our aim was to describe the mutation spectrum of TP53 somatic mutations in patients (pts) with glioma. MATERIAL AND METHODS This was a prospective multicenter study of patients with glioma diagnosed at four different institutions in Spain. Next-generation sequencing (NGS) of formalin-fixed paraffin-embedded (FFPE) or fresh tumor samples were used for sequencing the TP53 gene in an Illumina Miseq instrument (Illumina, Inc.). Only TP53 pathogenic mutations were considered as valid and are reported here. RESULTS Between February 2017 and March 2020, 61 glioma patients (pts) were enrolled among which 17 different pathogenic mutations in TP53 were detected. Mutant allele frequency (MAF) was > 4% in all cases. TP53 pathogenic mutations occurred at the following loci: L145P, R158H, R175H, H193R, G199V, R202C, R213X, H214R, Y234C, R248Q, I255S, E271Vfs*36, R273C, P278T, G278T, G279E, R280K. Additional clinical characteristics and survival results will be presented at the meeting. CONCLUSION TP53 occur frequently in glioma but widely distributed across the whole exome. The contribution of each specific pathogenic TP53 mutation in gliomas should be further studied.