Analysis of the molecular spectrum of brain stem gliomas through CSF-sourced circulation tumor DNA sequencing

Ref: Pan C,et al.
 Acta Neuropathol2018 Nov 20doi: 10.1007/s00401-018-1936-6Thecerebral glioma is a group of molecular heterogeneous diseasesBecause tumors are located in important functional areas, there are very few treatments available, and difficulties are made to remove safely, and even biopsies can be challenging, the analysis of routine molecular spectrums and the development of personalized treatment options are limitedChangcun Pan, of The medical surgery at Theinjar Hospital of capital medical university, and others sequenced the circulating tumor DNA (circulating tumor DNA, ctDNA) in CSF by collecting cerebrospinal fluid (CSF) in patients with cerebral stem glioma, and performed a molecular spectrum analysis of the tumor, which was published online in Acta Neuropathin, November 2018the study included 57 patients with brain stem glioma, all CSF specimens were collected prior to removal of the tumor, 52 (91.2%) were collected directly during surgery CSF, 2 cases (3.5%) were obtained through ventricle-abdominal shunt, and 3 cases (5.3%) were obtained through waist perbesyThe CSF-sourced ctDNA is then sequenced in depth with the glioma-related gene and paired with tumor DNA in the blood (Figure 1)In 47 (82.5%) CSF-derived ctDNA specimens, one or more tumor gene mutations were foundIn 37 patients with one or more genetic mutations in primary tumors, 36 (97.3%) CSF-derived ctDNA did have genetic mutations; In 10 patients with genotyped tumor gene mutations negative, 3 (30%) detected somatic cell changes in CSFThe sensitivity of gene mutations detected with plasma ctDNA was significantly worse than that of CSF source ctDNA (38% vs100%)Diagram 1A flow diagram of the sequence of genes using CSF source ctDNA a Distribution of brain stem tumors, most of which are located in the bridge brain or myelin; b.ctDNA into CSF; c.CSF source ctDNA collection methods: ventricular-abdominal shunt or waist perforation; d For specific patients, peripheral blood separation plasma ctDNA studies have shown that cDNA depth sequencing from CSF sources is a reliable technique for detecting mutations in brain stem tumor-specific genes, which can replace brain stem tumor biopsies for molecular spectrometry.