HCMDB (Human Cancer Metastasis Database) is an integrated database designed to store and analyze large scale expression data of cancer metastasis. A total of 124 previously published transcriptome datasets were collected from Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA). Transcriptomes were compared to examine the expression of metastasis-associated genes. In the current version of HCMDB, it contains 29 cancer types derived from more than 455 experiments. To annotate those potentially metastasis-related genes, a total of 2183 genes (1901 protein-coding genes, 24 long non-coding RNAs and 203 miRNAs) were curated based on more than 7,000 published literatures.

An easy-to-use interface was constructed to query and browse cancer metastasis related genes. HCMDB will become a powerful tool to provide a genome-wide view of transcriptomic changes associated with tumor metastasis.