The most well-studied sequences in the human genome are those of protein-coding genes. However, the coding exons of these genes account for only１．５％ of the genome. In recent years, FANTOM and ENCODE projects reveal that more than ８０％ of the human genome is transcribed into RNAs that do not encode protein. It has become increasingly apparent that the non-protein-coding RNAs （ncRNAs） are of crucial functional importance : for normal development and physiology, and for disease. In particularly cancer, it is increasing evidence that not only miRNAs but also other ncRNAs, such as large intergenic non-coding RNAs （lincRNAs） and long non-coding RNAs （lncRNAs）, function as oncogenic ncRNAs and tumor-suppressive ncRNAs
