TiSMeD: A tissue-specific methylation and expression database for biomarker and translational applications

Tissue-specific methylation sites (TSMs) are important epigenetic features associated with gene regulation, tissue development, and disease pathogenesis. However, the lack of comprehensive and reliable resources for TSMs restricts advancements in epigenetic and translational research. We present TiSMeD (http://www.bio-add.org/TiSMeD/), a multi-omics database integrating 6,782 DNA methylation, 16,894 transcriptome, and 241 proteome profiles across 48 normal human tissues. Using a scoring framework based on SPM adjust and Tscore, we identified 67,427 high-confidence TSMs, 4,607 tissue-specific genes, and 2,833 tissue-specific proteins, along with over 11 million housekeeping methylation sites. TiSMeD enables interactive exploration and data retrieval, supporting biomarker discovery and disease research. We demonstrate its utility in tracing the tissue-of-origin of cell-free DNA (cfDNA), prioritizing 1,849 cancer biomarkers from The Cancer Genome Atlas (TCGA), and constructing a multi-cancer tracing and diagnostic model achieving 95.7% accuracy. TiSMeD serves as a robust, user-friendly platform integrating multi-omics data to advance epigenetic research and biomarker translation.