The roles of extrachromosomal DNA in tumorigenesis and therapeutic resistance in cancer.

Extrachromosomal DNA (ecDNA) is a form of circular DNA that exists independently of chromosomes. Predominantly observed in tumor cells, ecDNA represents a key manifestation of genomic instability in cancer. In contrast to chromosomal DNA, ecDNA has a circular structure, often includes intact or fragmented gene sequences, and exhibits high copy number variation. Recent studies have shown that oncogene amplification on ecDNA is prevalent in many cancer types. This illustrates the significance of its role in the development and progression of cancer. Furthermore, ecDNA can induce drug resistance and adversely affect patient prognosis via various mechanisms, demonstrating considerable biological and potential therapeutic significance in preclinical investigations. This review outlines the key characteristics of ecDNA, analyzes its role in carcinogenesis and drug resistance, and evaluates current detection methods, aiming to explore its potential as a therapeutic target in cancer treatment.