This was accompanied with the decreased expression of UCP-2 in both mRNA and protein levels, indicating that the miR133a/UCP-2 is linked with chemotherapy-resistance in breast cancer.Furthermore, the essential role of UCP-2 in miR133a-induced Doxorubicin sensitivity was further validated by the finding that knockdown of UCP-2 could sensitize MCF-7/Dox cells to Doxorubicin treatment in vitro. The gene discussed is UCP2; the disease is breast cancer.