Abstract: The discovery of microRNA (miRNA) has opened up a new train of thought for the diagnosis and treatment of esophagus cancer. let-7 is one of the most widely research of miRNA. In a variety of tumors, the expression of let-7 is downregulated. let-7 can play the role of tumor suppressor gene by targeting to high mobility group A2 (HMGA2) and inhibit the cell proliferation. Recent studies have shown that the lower the degree of differentiation of cells, let-7 expression level is lower. It is expected as a symbol of poorly differentiated tumors. In addition, let-7 and esophagus cancer′s radiation and chemotherapy sensitivity are closely related.

Key words: Esophagus neoplasms, Therapy, Mechanism, let-7