Circulating tumor cells atlas – an open-access platform capturing tumor cells heterogeneity during cancer dissemination

Circulating tumor cells (CTCs) are key cellular intermediates in the metastatic cascade and provide a minimally invasive window into tumor heterogeneity and evolution during metastatic progression. Despite this potential, the broader clinical and research utility of CTC-based liquid biopsy remains limited by the lack of standardized, image-based reference resources. We introduce CTC Atlas ( www.CTCAtlas.org ), an open-access platform integrating high-resolution images of diverse CTCs and other circulating tumor-associated cells with technical, clinical, and multi-omics data. CTC Atlas aims to support CTC identification, cross-laboratory comparisons, and clinical implementation of variable CTC-based assays. It also provides a reference framework for studying phenotypic heterogeneity during tumor dissemination, and matched circulating microenvironment associated with metastatic progression.