Downregulation of miR-221-3p and upregulation of its target gene PARP1 are prognostic biomarkers for triple negative breast cancer patients and associated with poor prognosis

// Ling Deng 1, * , Qianqian Lei 1, 2, * , Yu Wang 1 , Zhu Wang 1 , Guiqin Xie 1 , Xiaorong Zhong 1 , Yanping Wang 1 , Nianyong Chen 3 , Yan Qiu 4 , Tianjie Pu 4 , Hong Bu 4 and Hong Zheng 1, 3 1 Laboratory of Molecular Diagnosis of Cancer, Clinical Research Center for Breast, State Key Laboratory of Biotherapy, National Collaborative Innovation Center for Biotherapy, West China Hospital, Sichuan University, Chengdu, China 2 Department of Radiation Oncology, Chongqing Cancer Institute 95% CI, 0.263–0.879; p = 0.017) of TNBC patients. High expression of its target gene PARP1 predicted poorer 5-year DFS (HR = 2.236, 95% CI, 1.209-4.136, p = 0.010). MiR-221-3p down-regulated PARP1 by targeting its 3'-untranslated region. In conclusion, low miR-221-3p expression may contribute to the poor outcome of TNBC patients through regulating PARP1 . MiR-221-3p likely plays a role as a PARP1 inhibitor by directly regulating PARP1 expression, thereby affecting the prognoses of TNBC patients.