Abstract
Extrachromosomal DNA (ecDNA) is a special class of circular DNA in eukaryotes, which is independent of conventional chromosomes. These circular molecules play important roles in biology, especially in cancer biology. The emergence of sequencing technologies such as CCDA-seq and Amplicon Architect has led to a progressive unraveling of the mystery of ecDNA. Consequently, insights into its function and potential applications have begun to surface. Among these studies, the most noteworthy research pertains to cancer-related investigations into ecDNA. Numerous studies have underscored the significance of ecDNA in the pathogenesis of cancer and its role in accelerating cancer evolution. This review provides an overview of the source, structure, and function of ecDNA, while compiling recent advancements in ecDNA in the field of cancer. Nonetheless, further research is imperative to determine its effectiveness and specificity as a biomarker for early cancer detection.