Combined evaluation of both WEE1 and phosphorylated cyclin dependent kinase 1 expressions in oral squamous cell carcinomas predicts cancer recurrence and progression

Background/purpose: WEE1 is a mitotic inhibitor at G2 checkpoint of the cell cycle that negatively regulates cyclin-dependent kinase 1 (CDK1) through inhibitory phosphorylation. This study assessed whether the expressions of both WEE1 and phosphorylated CDK1 in specimens of oral squamous cell carcinoma (OSCC) might predict the OSCC recurrence and progression. Materials and methods: This study used immunohistochemistry to examine the expressions of WEE1 and phosphorylated CDK1 proteins in 75 specimens of OSCC and 30 specimens of normal oral mucosa (NOM). Results: The mean WEE1 labeling index (LI) was significantly lower in 75 OSCC samples than in 30 NOM samples (P < 0.001), whereas the mean phosphorylated CDK1 LI was significantly higher in 75 OSCC samples than in 30 NOM samples (P < 0.001). We found a significant association of low WEE1 LI (<21%) with OSCC recurrence (P = 0.047) and a significant association of low phosphorylated CDK1 LI (<10%) with larger tumor size (P = 0.011) and more advanced clinical stages (P = 0.021) of OSCC. Conclusion: Combined evaluation of WEE1 and phosphorylated CDK1 LI in specimens of OSCC may predict the OSCC recurrence and progression.