2 1Department of Breast Surgical Oncology, Cancer Institute and Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, People’s Republic of China; 2The 2nd Department of Breast Cancer, Tianjin Medical University Cancer Institute and Hospital, Tianjin, People’s Republic of China Correspondence: Liqiang Qi Department of Breast Surgical Oncology, Cancer Institute and Cancer Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, No. 17, Panjiayuan Nanli, Chaoyang District, Beijing, 100021, People’s Republic of China Tel +86-10-67781331 Purpose: circHIPK3 has carcinogenic or anti-tumor effects on different cancers. However, there is no relevant research showing whether circHIPK3 was involved in breast cancer (BCa). In this research, the aim was to analyze the function and possible molecular mechanism of circHIPK3 in BCa.