Table 1.

The classification of extrachromosomal circular DNA in cancer

Name	Size range	Replication	Function
SpcDNA	Several hundred bp	Self-replicate	Contributing to telomere homeostasis
T-circles/c-circles	0.3 to 30 Kb	Self-replicate	Serving as templates for telomere elongation
MicroDNA	100 to 400 bp	Self-replicate	Regulating microRNAs
ERCs	19.3 to 40.4 Kb	Self-replicate	Serving as templates for ribosomal RNA transcription
DMs	A few to several Mb	Self-replicate	Leading to oncogene amplification and overexpression