Background: Although p21 is an important component that regulates cell-cycle progression, no consensus has been reached about its clinicopathological significance in esophageal squamous cell carcinoma (ESCC). In the present study, we investigated its prognostic significance and correlation with cyclin-D1 (CCND1) expression in ESCC.
Materials and methods: The p21 labeling index (LI) was calculated by immunohistochemistry for 69 primary tumor samples obtained from patients with ESCC who had undergone curative esophagectomy, and correlations between p21 LI and various clinicopathological features, prognosis, and CCND1 LI were studied.
Results: The p21 LI of these tumors ranged from 2.0% to 57.0% (median=28.4%, mean±SD=27.3% ± 13.0). p21 LI was positively correlated with CCND1 LI. When patients were divided into two groups using a p21 LI cut-off value of 30%, the 5-year survival rate of patients with p21 LI of ≥ 30% was 80.0%, which was significantly higher than that of patients with p21 LI of <30% (55.5%). Furthermore, when patients were divided into four groups according to p21 and CCND1 expression, the 5-year survival rate of patients with p21 LI of <30% and CCND1 LI of ≥ 45% was the lowest (44.4%). Multivariate analysis demonstrated that venous invasion, lymphatic invasion, and p21 LI were independent prognostic factors.
Conclusion: Our results indicate that p21 LI is correlated with CCND1 LI and can be used as an independent prognostic factor for patients with ESCC following selection of a suitable cut-off value.
Keywords: esophageal squamous cell carcinoma; p21; prognostic factor.