Abstract: microRNA (miRNA) is a kind of non-coding single-stranded RNA with a length of 20 ~ 24 nucleotides, which is called post-transcriptional regulatory factor. miRNA regulates its target genes after transcription. The changes of miRNA expression play important regulatory roles in the occurrence and development of many diseases. microRNA 124 (miR-124) is one of the research hotspots at present. It is lowly expressed in many types of tumors, and has played important roles in suppressing tumor growth and metastasis through regulation of cell proliferation, invasion and apoptosis. It has closely participated in the occurrence, development and prognosis of malignant tumors. This review aims to make a summary of the mechanism of miR-124 in non-malignant and malignant diseases to provide theoretical evidence for their diagnosis and treatment.

Key words: microRNA, miR-124, tumor