Abstract: MiRNA can reduce the stability of the messenger RNA or inhibit the translation of the messenger RNA by targeting its 3’-Untranslated Region(3’UTR),thereby negatively regulate the expression of the target gene .Nevertheless , some mRNAs;pseudogenes;long non-coding RNAs（LncRNA）and circRNAs can competitively combine with the same miRNAs by miRNA respone elements(MREs),removing or reducing the inhibition of genes targedted by the miRNAs and regulating the expression of the tagert genes .This mechanism is called competing endogenous RNA(ceRNA) hypothesis. In the process of tumorigenesis，mRNAs;pseudogene;LncRNA and circRNA can function as a ceRNA and promote or inhibit the occurrence of tumor by competiting to binding the same miRNAs that can promote or suppress tumorigenesis.

Key words: ceRNA、miRNA、target gene、tumorigenesis