p53 is an independent prognostic factor in operable esophageal squamous cell carcinoma: a large-scale study with a long follow-up

The p53 protein is involved in many biological functions in cancer, such as cell cycle arrest, DNA repair, apoptosis, senescence, DNA metabolism, angiogenesis, and cellular differentiation. However, the association between p53 expression and clinicopathological findings or prognosis in esophageal squamous cell carcinoma (ESCC) is controversial. We designed a large-scale study of 830 operable ESCC patients with a long follow-up to investigate the relationship between p53 expression and the clinicopathological characteristics and prognosis of patients. Immunohistochemistry was used to detect p53 protein expression. When the patients were divided into two groups, a positive expression group and a negative expression group, p53-positive expression positively correlated with a poorer differentiation level (P = 0.044). The overexpression of p53 was associated with a more advanced clinical stage (P = 0.015). A total of 775 patients were available for survival analysis. The median OS of 160 patients who had p53-positive expression and 486 patients who had p53-negative expression were 58.8 and 46.3 months, respectively (P = 0.021); the median PFS of the two groups were 39.6 and 27.5 months, respectively (P = 0.015). Lymph node metastasis, gender, differentiation, depth of invasion, and p53 protein expression were proven to have an influence on both OS and PFS in a univariate analysis. In the multivariate analysis, p53-positive expression maintained its independent prognostic impact on OS (P = 0.048) and PFS (P = 0.039), as did lymph node metastasis, differentiation, and depth of invasion. We identified that p53 protein-positive expression can serve as an independent, unfavorable prognosis biomarker in ESCC.