TERTp Mutation Detection in Plasma by Droplet-Digital Polymerase Chain Reaction in Spinal Myxopapillary Ependymoma with Lung Metastases.
BACKGROUND
Spinal myxopapillary ependymoma (SP-MPE) is a subgroup of ependymomas in which after initial gross tumor resection, recurrences occur in more than half of the patients. Anaplastic transformation may also occur and contributes to intraneural and extraneural metastatic dissemination. Extraneural metastases from SP-MPE are rare and worsen the prognosis. In this situation, the noninvasive detection of recurrent somatic mutations in the circulating tumor DNA (ctDNA) from plasma is challenging. Telomerase-reverse transcriptase gene promoter (TERTp) mutation has been identified in a subset of ependymomas with aggressive behavior.


CASE DESCRIPTION
We report on a patient with TERTp mutated SP-MPE presenting with an extraneural anaplastic metastatic dissemination after iterative local recurrences. From the initial SP-MPE to pleural anaplastic lesion, TERTp C228T mutation was present with allele frequency varying from 33% to 39%. Interestingly, TERTp mutation was also detected by droplet digital polymerase chain reaction in the plasma with a frequency of 2.1% at the time of pleural metastases, highlighting that ctDNA is released in plasma of patients suffering from SP-MPE with extraneural metastatic dissemination.


CONCLUSIONS
Despite the rarity of this evolution, plasmatic liquid biopsy appears to be a useful diagnostic and follow-up tool in a subset of primary brain tumors.
['Deniel|Anne|A|', 'Marguet|Florent|F|', 'Beaussire|Ludivine|L|', 'Tobenas-Dujardin|Anne-Claire|AC|', 'Peillon|Christophe|C|', 'Gambirasio|Marco-Achille|MA|', 'Veresezan|Ovidiu|O|', 'Magne|Nicolas|N|', 'Di Fiore|Frederic|F|', 'Laquerrière|Annie|A|', 'Sarafan-Vasseur|Nasrin|N|', 'Fontanilles|Maxime|M|']
D000328:Adult D014408:Biomarkers, Tumor D000073888:Cell-Free Nucleic Acids D004273:DNA, Neoplasm D004806:Ependymoma D005260:Female D006801:Humans D008175:Lung Neoplasms D009154:Mutation D016133:Polymerase Chain Reaction D011401:Promoter Regions, Genetic D013120:Spinal Cord Neoplasms D019098:Telomerase
Spinal myxopapillary ependymoma Circulating tumor DNA Liquid biopsy Droplet digital PCR Metastasis TERT promoter mutation