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Table 2 The mechanism of ecDNA genesis

From: Novel insights into extrachromosomal DNA: redefining the onco-drivers of tumor progression

Model

Mechanism

Reference

Episome

Replication bubble drop from the chromosome to produce an episome and then the episome replicates and recombines to form ecDNA.

[52,53,54,55]

Translocation-excision-deletion-amplification

Two chromosomes translocate with subsequent excision and deletion at the regions neighboring translocation breakpoints, and then the separate fragments amplify and circularize to form ecDNA.

[56]

Chromothripsis

Chromosomes are isolated into fragments through an error in cell segregation, and the fragments connect randomly to produce ecDNA.

[57,58,59]

A multistep evolutionary process

The single-chromosome ancestral episomes undergo a series of discrete mutation events, including recombinations, deletions and duplications to produce various ecDNAs.

[60, 61]