MicroRNAs (
miRNAs) are often deregulated in
cancer and are thought to play an important role in
cancer development. Large amount of differentially expressed
miRNAs have been identified in various
cancers by using high-throughput methods. It is therefore quite important to make a comprehensive collection of these
miRNAs and to decipher their roles in
oncogenesis and
tumor progression. In 2010, we presented the first release of dbDEMC, representing a database for collection of differentially expressed
miRNAs in human
cancers obtained from microarray data. Here we describe an update of the database. dbDEMC 2.0 documents 209 expression profiling data sets across 36
cancer types and 73 subtypes, and a total of 2224 differentially expressed
miRNAs were identified. An easy-to-use web interface was constructed that allows users to make a quick search of the differentially expressed
miRNAs in certain
cancer types. In addition, a new function of 'meta-profiling' was added to view differential expression events according to user-defined
miRNAs and
cancer types. We expect this database to continue to serve as a valuable source for
cancer investigation and potential clinical application related to
miRNAs. dbDEMC 2.0 is freely available at http://www.picb.ac.cn/dbDEMC.