Table 1.

Selected studies using ddPCR and NGS to detect ctDNA in brain gliomas

Tumor	Sample type	Patients(n)	Detection methods	Detection index	References
Gliomas	CSF, urine, and plasma	49	ddPCR	IDH1	(Tuna et al. 2022)
Pediatric high-grade and diffuse midline glioma, H3K27-altered	Plasma, serum, CSF, cystic fluid, and tumor samples	32	ddPCR	H3F3A_K27M; BRAF-V600E	(Izquierdo et al. 2021)
Gliomas	CSF	13	sWGS	DNA fragmentation and copy number alterations	(Mouliere et al. 2018b)
GBM and other primary brain tumors	Blood samples	419	NGS	Targeted NGS sequencing	(Piccioni et al. 2019)
Brainstem gliomas	CSF, plasma, and tumor samples	57	NGS	68 genes	(Pan et al. 2019)
Pediatric solid tumors	Blood samples	39	NGS and sWGS	67 genes	(Stankunaite et al. 2022)
Gliomas	CSF and tumor samples	26	NGS	520 genes	(Guo et al. 2022)
GBM	CSF and tumor samples	10	WES	ctDNA mutations	(Duan et al. 2020)
Gliomas	TISF and tissue samples	10	NGS	68 genes	(Sheng et al. 2021)
Gliomas	TISF and tumor samples	107	NGS	68 genes	(Sheng et al. 2023)
Diffuse midline glioma, H3 K27-altered	CSF, plasma, tumor samples, and human primary pediatric glioma cells	CSF (n = 6), plasma (n = 4)	ddPCR	H3F3A c.83A > T	(Li et al. 2021)
Pan-cancers	Blood and tumor samples	200	sWGS	Fragment sizes	(Mouliere et al. 2018a)

ddPCR Droplet digital PCR; NGS next-generation sequencing; sWGS shallow whole-genome sequencing; WES whole-exome sequencing; ctDNA circulating tumor DNA; GBM glioblastoma; CSF cerebrospinal fluid