eccDNABase: A Comprehensive and High-Quality Database for Extrachromosomal Circular DNA

Extrachromosomal circular DNA (eccDNA) refers to small, circular DNA molecules that originate from chromosomal sequences and are prevalent across nearly all eukaryotic organisms. In humans, eccDNAs are widely distributed in normal tissues, cancerous tissues, and body fluids, where they play important roles in tumorigenesis and are often associated with poor clinical outcomes. Given their biological and clinical significance, a well-integrated and high-quality database is essential for advancing eccDNA-related research. To address this need, we developed eccDNABase, a comprehensive and curated resource for browsing, searching, and analyzing eccDNAs across multiple species. The database systematically catalogs eccDNA-disease associations from diverse tissues and organisms. Currently, eccDNABase contains 1,875,452 eccDNA-disease associations, encompassing 8,398 ecDNA entries across nine species, 63 diseases, and healthy individuals. Each entry provides detailed information, including eccDNA ID, type, chromosomal localization, species, tissue or cell line source, disease name and Disease Ontology ID, overlap length and percentage with genes, oncogene overlap, detection method, and links to literature and source databases. Given its extensive and curated datasets, eccDNABase serves as a valuable resource for both basic and translational research, offering deeper insights into the role of eccDNA in health and disease. The database is publicly accessible at http://cgga.org.cn/eccDNABase/.