Targeting MicroRNAs for Personalized Cancer Therapy

and CD24 –/lo have aberrant expression of miRNAs and much greater self-renewal activity, proliferation and tumor initiation than other cancer cells. The high expression of miR-21, miR-181a and miR-181b has been observed in breast CSCs; however, these cells express very low levels of let-7, miR-34, miR-200, miR-29, miR-30a and miR-93. Similar to breast CSCs, prostate CSCs express a very low level of miR-34, which targets AR and CD44 expression. Therefore, both breast and prostate CSCs have a high expression of CD44. However, prostate CSCs express low levels of other miRNAs, different from those expressed by breast CSCs. The expression of miR-320 and miR-708 is significantly downregulated in prostate CSCs, unlike in breast CSCs. Molecular mechanistic studies show that miR-320 and miR-708 could inhibit tumor formation from CSCs by targeting β-catenin or Introduction