TERT Promoter Mutation Detection in Cell-Free Tumor-Derived DNA in Patients with IDH Wild-Type Glioblastomas: A Pilot Prospective Study

Abstract

We conducted a pilot study to assess the feasibility and the potential implications of detecting promoter (p)-mutant cell-free tumor-derived DNA (tDNA) in the cerebrospinal fluid (CSF) and plasma of glioblastoma patients. Matched CSF and plasma samples were collected in 60 patients with glial tumors. The CSF collection was obtained during surgery, before any surgical manipulation of the tumor. The extracted tDNA and corresponding tumor DNA samples were analyzed for p and isocitrate dehydrogenase ( hotspot mutations. In addition, the variant allele frequency (VAF) of p mutation in the CSF-tDNA was correlated with tumor features and patients' outcome. Thirty-eight patients had p-mutant/ wild-type glioblastomas. The matched p mutation in the CSF-tDNA was successfully detected with 100% specificity (95% CI, 87.6-100%) and 92.1% sensitivity (95% CI, 78.6-98.3%) ( = 35/38). In contrast, the sensitivity in the plasma-tDNA was far lower [ = 3/38, 7.9% (95% CI, 1.6-21.4%)]. We concordantly observed a longer overall survival of patients with low VAF in the CSF-tDNA when compared with patients with high VAF, irrespective of using the lower quartile VAF [11.45%; 14.0 mo. (95% confidence interval, CI, 10.3-17.6) vs. 8.6 mo. (95% CI, 4.1-13.2), = 0.035], the lower third VAF [13%; 15.4 mo. (95% CI, 11.6-19.2) vs. 8.3 mo. (95% CI, 2.3-14.4), = 0.008], or the median VAF [20.3%; 14.0 mo. (95% CI, 9.2-18.7) vs. 8.6 mo. (95% CI, 7.5-9.8), = 0.062] to dichotomize the patients. This pilot study highlights the value of CSF-tDNA for an accurate and reliable detection of p mutations. Furthermore, our findings suggest that highp mutation VAF levels in the CSF-tDNA may represent a suitable predictor of poor survival in glioblastoma patients. Further studies are needed to complement the findings of our exploratory analysis. .

Mechanisms underlying the activation of TERT transcription and telomerase activity in human cancer: old actors and new players

“…However, a number of problems (such as unstable TERT mRNA and enzymatic activity) impede reliable utility of a direct TERT expression or telomerase activity assay for cancer diagnostic or monitoring purpose, whereas widespread TERT promoter mutations in different tumors pave new avenues [31]. The non-invasive detection of a mutant TERT promoter is especially attractive and has been evaluated in plasma, urine and cerebrospinal fluid (CSF) for the diagnosis/monitoring of HCC, bladder cancer and glioblastoma, respectively [31,[87][88][89][90]. These proof-of-concept studies have shown usefulness of the mutant TERT promoter as a non-invasive assay biomarker for these malignancies.…”

Cerebrospinal fluid cell-free tumour DNA as a liquid biopsy for primary brain tumours and central nervous system metastases

“…The analysis of the CSF ctDNA of a cohort of diffuse gliomas indicated that they could be subtyped by analysing the IDH1 and IDH2, ATRX, TP53, TERT, H3F3A and HIST1H3B mutational status, facilitating the classification of diffuse gliomas and providing prognostic information [28]. Moreover, the presence of mutations in the TERT promoter found in CSF ctDNA correlated with outcome [37]. In the case of diffuse midline gliomas, the detection of H3F3A and HIST1H3B mutations in the CSF could confirm diagnosis [28].…”

Beyond the Blood: CSF-Derived cfDNA for Diagnosis and Characterization of CNS Tumors

“…Physiologic factors include those that limit the amount of tumorderived cfDNA present in the CSF. Multiple studies have shown that low grade tumors or those not directly communicating with the CSF space have low to undetectable tumor-derived cfDNA in the CSF Juratli et al, 2018;Martínez-Ricarte et al, 2018;Pan et al, 2019). Likewise, detection of tumor-derived cfDNA is less likely in patients with new onset disease (Pan et al, 2019).…”