Abstract: Muscle blind-like protein 1（MBNL1） is a class of RNA binding protein. As an alternative splicing factor of precursor mRNA（pre-mRNA）, it plays a fundamental role in the regulation of the development process and the post transcriptional regulation of specific transcripts, which affects multiple steps in the process of RNA maturation and expression, including pre-mRNA splicing,degradation, RNA output, stability maintenance, modification and translation. MBNL1 was first considered as a contributing factor in the pathogenesis of myotonic dystrophy. With going deep into the research, its role in a variety of non-tumor and tumor diseases has become increasingly prominent. Studies have shown that MBNL1 is abnormally expressed in many types of tumors and is closely related to the occurrence, development and metastasis of various malignant tumors, such as gastric cancer, colorectal cancer,breast cancer, prostate cancer, glioblastoma, lung cancer, hematological system tumors, etc. According to different cell types and development environments, the changes of MBNL1 protein levels in normal and tumor cells are diverse. MBNL1 can not only act as a transcriptional activator to promote the occurrence and development of tumors, but also play as a transcriptional repressor to inhibit the growth and metastasis of tumors. The present review summarizes the molecular mechanism, biological characteristics,expression and function of MBNL1 in the occurrence and development of various malignancies to provide several new insights into tumor-targeted therapy and prognosis evaluation.

Key words: muscle blind-like protein 1（MBNL1）, alternative splicing, splicing factor, malignant tumor, molecular mechanism