Polo‐like kinase 4 correlates with greater tumor size, lymph node metastasis and confers poor survival in non‐small cell lung cancer

BACKGROUND: Our study aimed to investigate the association of polo‐like kinase 4 (PLK4) expression with tumor features as well as survival in non‐small cell lung cancer (NSCLC) patients. METHODS: Five hundred and sixty NSCLC patients who underwent pulmonary resection were recruited, and their tumor specimens were obtained. Immunohistochemistry (IHC) staining was performed to assess PLK4 expression in tumor specimen. Follow‐up documents were reviewed, and the disease‐free survival (DFS) and overall survival (OS) were evaluated. RESULTS: According to IHC staining, there were 277 (49.5%) patients with PLK4 low expression and 283 (50.5%) patients with PLK4 high expression. PLK4 high expression was further classified into three different classes: high+, high++, high+++, and 122 (21.8%), 127 (22.7%), 34 (6.1%) patients were with PLK4 high+, high++, high+++ expression, respectively. Polo‐like kinase 4 expression was correlated with larger tumor size, LYN metastasis, and higher TNM stage. As for survival, DFS and OS were lower in patients with PLK4 high expression compared with patients with PLK4 low expression. In addition, DFS and OS were the lowest in patients with PLK4 high+++ expression, followed by those with PLK4 high++ expression, PLK4 high+ expression, and then patients with PLK4 low expression. Univariate and multivariate Cox's proportional hazard regression model analyses further disclosed that PLK4 was an independent predictive factor for poor DFS and OS in NSCLC patients. CONCLUSION: Our study preliminarily illuminates the clinical implication of PLK4 in NSCLC, while further studies are still needed to explicit the value of PLK4 in surveillance and treatment of NSCLC.