Low Expression of Polo-like Kinase 1 is Associated with Poor Prognosis in Liver Cancer

Aim: To determine the expression level of polo-like kinase 1 (PLK1) in liver cancer specimens and assess its prognostic value. Methods: Postconsent, 85 liver cancer specimens and their paired adjacent normal liver tissues were obtained during hepatectomy. The samples were clinicopathologically characterized, followed by immunohistochemical staining to determine the expression levels of PLK1. The study subjects were followed up for 2–117 months (the median follow-up period was 26 months) to assess their overall survival time. Results: Cancer specimens demonstrated significantly lower expressions of PLK1 than normal hepatocytes (76% vs . 95%, respectively, P 5 cm, P = 0.045, χ 2 test), liver capsule invasion ( P = 0.004, χ 2 test), and American Joint Committee on Cancer Stage IV ( P = 0.007, χ 2 test). The survival time of PLK1 negative subjects was significantly shorter than that of PLK1 positive cases ( P = 0.041, log-rank test). Conclusion: Downregulation of PLK1 expression demonstrates a strong correlation with liver cancer and may serve as a critical indicator of poor prognosis of the disease.