The circTeloDIAG: a New Approach of Liquid Biopsy for the Diagnosis and Follow-up of Patients With Glioma Tumor

Gliomas, heterogeneous and aggressive tumors awaiting new therapeutic approaches.

Gliomas are the most frequent primary brain tumors, with 2,500 to 3,000 new cases per year in France. They concern the elderly but can also affect children and young adults. Their diagnosis is often complex (differential diagnoses, delicate classification). However, this diagnosis is essential to determine the therapeutic management. Thus, while grade I gliomas (infrequent) are curable by surgery or have a slow progression, grades II to IV have a cost in terms of therapeutic costs (surgery and radio-chemotherapy), in connection with a prognosis ranging from heavy 10-15 years for grades II to only 15 months for glioblastoma (grade IV). New biotherapies (such as anti-VEGF) have not improved the prognosis and to date there are no targeted therapies or immune systems that have shown a benefit.

It is more than ever necessary to propose targeted treatments against alterations of each type of glioma and to develop in parallel the therapeutic tests allowing their prescription.

DIAGNOSIS OF GLIOMAS: IMPORTANCE OF BIOMARKERS

The diagnosis of gliomas was subject to a high rate of inter-observer discrepancies. Molecular criteria have recently made it possible to refine and secure the diagnosis1. Thus, in hospital routine, mutations in Isocitrate Dehydrogenases (IDH1 and 2), 1p19q deletion, EGFR amplification, loss of CDKN2A, mutations in histones H3.3 and H3.1 (G35R / V, K28M), methylation of MGMT, as well as two telomeric markers: mutations of the TERT promoter (TERTmt) and the deletion of ATRX (lost ATRX) (see below). Thus, the new "histo-molecular" classification of WHO1 (2016) and its following updates define different classes of gliomas: