Ph. D thesis at the faculty of Sciences College at the University of Basrah (Using of Let-7a miRNA in Gene Therapy as Anti-Tumor Control of Breast Cancer), and showed the researcher's thesis (Suhyila Fadhil Ali) raising of expression level of let-7a in MCF-7 breast cancer cell line. Thesis aims to restoration the level of let-7a in breast cancer and analysis the effects of this gene on breast cancer cell line by assay of apoptosis and proliferation  and concluded the induction of apoptosis while the proliferation was reduced, and recommended using of let-7a level as biomarker diagnosis of breast cancer and encourage of combination in chemo and radio-therapy with let-7a