Abstract

Background: Expression of P¹⁶ gene that is the key regulatory protein of the cell cycle has been linked with the prognosis of Esophageal squamous cell carcinoma patients.

Materials and method: By immunohistochemistry, we examined the expression status of P¹⁶ of 110 esophageal squamous cell carcinoma patients on the tissue microarrays (TMAs). The nuclear staining intensity was calculated by immunoreactivity score ranging from (0-12) and split them into two groups: No-expression & Overexpression group.

Result: Postoperatively median follow-up period of our study was 70 months. Down-regulation of P¹⁶ expression pointedly predicted decreased 5-year overall survival (P=0.001) and progression-free survival, which is statistically significant & demonstrated by Kaplan-Meier estimates using the log-rank test. Hence, P¹⁶ protein acts as an independent prognostic factor for overall survival and progression-free survival that demonstrated by multivariate Cox-regression analysis (HR=0.046 with 95% CI 0.006-0.333, P=0.002 and HR=0.064 with 95% CI 0.009-0.466, P=0.005 respectively OS & PFS).

Conclusion: P¹⁶ is a promising biomarker that is down regulated in ESCC patients and prognostic indicator for poor survival postoperatively.

Keywords: Esophageal squamous cell carcinoma; Metastasis; P¹⁶; Overall survival; Progression-free survival