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 (rs= - 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.

Invasive micropapillary carcinoma of the breast is a histologic subtype of breast cancer and associated with high incidence of lymphovascular invasion, lymph node metastasis and poor prognosis. The aim of this prospective study was to investigate the impact of precise pathologic diagnosis and individualized treatment on the outcomes of invasive micropapillary carcinoma of the breast. The study group included 2299 women with invasive micropapillary carcinoma diagnosed at Tianjin Medical University Cancer Institute and Hospital between January 2004 and December 2015. In the study group, specimens were examined with the method of whole-specimen orientation and serial sectioning, and patients received precise pathological diagnosis and individualized treatment. The control group of invasive micropapillary carcinoma consisted of 163 cases, identified through a retrospectively review of 9056 invasive carcinomas diagnosed at our institution between January 1989 and December 2003 using the standard pathology-evaluation method (i.e., not using the whole-specimen orientation and serial-sectioning method). The clinicopathological features, treatments and outcomes were compared between the two groups. The incidence of invasive micropapillary carcinoma in the study group was 6% (2299/39,714 cases), significantly higher than that of the control group (2%; 163/9056 cases). The 5-year disease-free survival in the study group was significantly higher than that in the control group (83.8 vs.45.4%; p < 0.05). The 5-year overall survival was significantly increased from 57.4% in the control group to 90.9% in the study group (p < 0.05). In the multivariate analysis, lymphovascular invasion, estrogen receptor status and lymph node metastasis were independent prognostic factors. Although invasive micropapillary carcinoma of the breast is associated with poor prognosis, precise pathologic diagnosis and individualized treatment improved the disease-free survival and overall survival of invasive micropapillary carcinoma patients. Precise pathological diagnosis is the premises for individualized treatments and for improving the outcomes of patients with invasive micropapillary carcinoma of the breast.

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