MicroRNAs (miRNAs) have been studied widely in organ development,inflammation,and tumorigenesis because of their inhibitory effects on long coding or non-coding target genes.In addition to the conventional miRNA/target RNA function,recent studies have shown that the interaction between a miRNA and a target RNAs is not unidirectional,the target RNA might act as a molecular sponge for miRNAs through their miRNA response elements (MRE),thereby de-repressing other RNA species sharing the same miRNA regulator(s).Such a scenario has been termed thecompeting endogenous RNA (ceRNA) effect[1].ceRNAs have emerged recently to add to the complexity of miRNA-mediated gene regulation,carrying significant potential implications for a variety of biological processes[2,3].However,a global view of their system-level properties across various types of cancers is still unknown.Here,we proposed a two-stage analysis method by systematically analyzing molecular profiles of 5203 tumors and miRNA regulations.