Abstract: MicroRNAs (miRNAs) are a group of small noncoding RNAs of about 22 nucleotides in length, which mediate the post-transcriptional gene modulation by annealing to incomplete complementary sequences in the 3’untranslated regions of target mRNAs. miR-103 as an important member of microRNA family, plays a regulatory role in multiple tumors; it also has a potential role in non-tumor diseases.