Abstract: let-7i-5p is a member of non-coding small molecule RNA (miRNA), which inhibits tumor growth, proliferation and migration through multiple targets and signaling pathways. It also has the effect of regulating tumor microenvironment to delay cancer progression and improve tumor drug resistance. This article reviews the research progress of the mechanism of let-7i-5p in liver cancer, breast cancer, colon cancer, cervical cancer, nasopharyngeal cancer, kidney cancer and glioblastoma. It is expected to explore the role that let-7i-5p can play as a new tumor marker to provide a new strategy for tumor prevention and treatment.

Key words: let-7i-5p, tumor, mechanism