Profiling of circulating glial cells for accurate blood-based diagnosis of glial malignancies

Here, we describe a blood test for the detection of glial malignancies (GLI-M) based on the identification of circulating glial cells (CGCs). The test is highly specific for GLI-M and can detect multiple grades (II-IV) and subtypes including gliomas, astrocytomas, oligodendrogliomas, oligoastrocytomas and glioblastomas, irrespective of gender and age. Analytical validation of the test was performed as per Clinical and Laboratory Standards Institute (CLSI) guidelines. Real-world performance characteristics of the test were evaluated in four clinical (observational) studies. The test has high analytical sensitivity (95%), specificity (100%) and precision (coefficient of variation [CV] = 13.7% for repeatability and CV = 23.5% for within laboratory precision, both at the detection threshold) and is not prone to interference from common drugs and serum factors. The ability of the test to detect and differentiate GLI-M from non-malignant brain tumours (NBT), brain metastases from primary epithelial malignancies (EPI-M) and healthy individual donors (HD) was evaluated in four clinical cohorts. Across these clinical studies, the test showed 99.35% sensitivity (95% confidence interval [CI]: 96.44%-99.98%) and 100% specificity (95% CI: 99.37%-100%). The performance characteristics of this test support its clinical utility for diagnostic triaging of individuals presenting with intracranial space-occupying lesions (ICSOL).