PLK4 and breast carcinoma: Polo-like kinase 4 (PLK4), a family member of polo-like kinases (PLKs), consists of an N-terminal kinase domain and a C-terminal Polo-box domain (PBD).6 Preceding studies illuminate that the PLK4 modulates the centriole duplication and therefore plays a crucial role in tumor growth, invasion, and metastasis in a series of solid carcinomas.7,8 In detail, PLK4 knockdown in vitro inhibits the cancer cell growth in breast cancer cell line7.