SCAR is the first cancer database combining single-cell transcriptome and spatial transcriptomic datasets covering the most cancer types, with 348 cancer subtypes available to date. Furthermore, SCAR includes the spatial transcriptomic data of 21 organs and 34 types of single-cell omics techniques. On the other hand, SCAR also provides a wide range of analytical and visualization tools in tumor cell types classification, biomarker selection, survival curve prediction etc. It will allow users to comprehensively evaluate the tumor microenvironment and immunological response for cancer studies.

SCAR aims to better understand and exploit all currently known scRNA-seq and spatial transcriptomic datasets of cancer types, giving the research community free access to combined single-cell and spatial transcriptomic data on tumor microenvironment and immunological response through a user-friendly interface. Future published cancer single-cell sequencing and spatial transcriptomic data will be updated into SCAR, and data generated by spatial transcriptomics or other multi-omics cellular information may be integrated into SCAR in the future. In summary, SCAR will continue to enrich and expand the full utilization of the valuable resources of cancer single-cell and spatial transcriptomic atlas for the scientific community.