Tumor polo-like kinase 4 protein expression reflects lymphovascular invasion, higher Federation of Gynecology and Obstetrics stage, and shortened survival in endometrial cancer patients who undergo surgical resection.

Background: Polo-like kinase 4 (PLK4) serves as a marker for tumor features and poor outcomes in cancers. This study aimed to explore the associations of tumor PLK4 protein expression with tumor characteristics and survival in endometrial cancer (EC) patients who underwent surgical resection.

Methods: This study included 142 EC patients who underwent surgical resection. Tumor tissue samples were obtained for tumor PLK4 protein expression detection via immunohistochemistry (IHC).

Results: Among EC patients, 26.1% had a PLK4 IHC score of 0, 24.6% had a score of 1-3, 27.5% had a score of 4-6, and 21.8% had a score of 7-12. Tumor PLK4 protein expression positively associated with lymphovascular invasion (P = 0.008) and Federation of Gynecology and Obstetrics (FIGO) stage (P = 0.005). Disease-free survival (DFS) was not different between patients with tumor PLK4 IHC scores > 0 and ≤ 0 (P = 0.154) but was reduced in patients with scores > 3 vs. ≤ 3 (P = 0.009) and > 6 vs. ≤ 6 (P < 0.001). Similarly, overall survival (OS) was not different between patients with scores > 0 and ≤ 0 (P = 0.322) but was shorter in patients with scores > 3 vs. ≤ 3 (P = 0.011) and > 6 vs. ≤ 6 (P = 0.006). After adjustment, a tumor PLK4 IHC score > 6 (vs. ≤ 6) (hazard ratio (HR): 3.156, P = 0.008) or > 3 (vs. ≤ 3) (HR: 3.918, P = 0.026) was independently associated with shortened DFS and OS.

Conclusion: A tumor PLK4 IHC score > 6 or > 3 associates with shortened DFS and OS in EC patients who undergo surgical resection.