Expression of Polo-Like Kinase 4(PLK4) in Breast Cancer and Its Response to Taxane-Based Neoadjuvant Chemotherapy

Purpose: Polo-like kinase 4(PLK4) is an important evolutionarily regulator involved in centrosome duplication. We here investigated the expression of PLK4 mRNA and PLK4 in breast cancer, and evaluated its predictive value for response to taxane-based neoadjuvant chemotherapy. Method: The PLK4 mRNA expression was measured in breast cancer tissues and corresponding normal breast tissues from 30 breast cancer patients by quantitative real-time polymerase chain reaction (PCR). The association of the expression of PLK4 with clinicopathological parameters and prognostic significance was evaluated in 154 cases of invasive breast cancer. In addition, we immunohistochemically examined the changes of PLK4 expression in biopsy and postoperative tumor specimens of another 64 breast cancer patients who received taxane-based neoadjuvant chemotherapy. Results: The level of PLK4 mRNA expression in cancerous tissues had a significant difference compared to the corresponding normal breast tissues (P= 0.021). There is a correlation of PLK4 expression with higher incidence of lymph node metastasis and distant metastasis or surrounding recurrence (P= 0.043; P= 0.006). High PLK4 expression was found to be a detrimental prognostic factor measured by overall survival (OS) (P= 0.003) and progress-free survival (PFS) (P= 0.003). Moreover, the results demonstrated that PLK4 expression was a negative predictor of response to taxane-based neoadjuvant chemotherapy (r(s)= -0.253, P= 0.044). Conclusion: The findings of this current study indicated that PLK4 expression in breast cancer could be a potential prognostic factor and a negative predictor of response to taxane-based neoadjuvant chemotherapy.