p53 protein expression and prognosis in squamous cell carcinoma of the esophagus

The p53 gene product is known to regulate cell growth and proliferation. Whereas the wild-type p53 protein suppresses cell growth, the mutated p53 protein acts as an oncogene. Mutations in the p53 gene usually result in p53 protein stabilization and accumulation; so that the gene product can be detected by immunohistochemistry. Recently, the immunohistochemical detection of the p53 protein was associated with prognosis in breast, colorectal, and other types of cancer. However, its prognostic role in esophageal cancer remains to be elucidated.

p53 expression in formalin fixed, paraffin embedded samples of 204 patients with primary squamous cell carcinoma of the esophagus, who underwent esophageal resection, were analyzed immunohistochemically with DO-1, a monoclonal antibody that detects wild-type and mutant forms of p53. The relationship between p53 immunoreactivity and prognostic factors was determined by the Chi-square test, and the prognostic impact of p53 protein expression was analyzed using univariate and multivariate survival analyses.

In 137 of 204 tumors (67.2%), nuclear immunoreactivity for the p53 protein was detected. There was no correlation with sex, age, pathologic tumor (pT) category, pathologic lymph node (pN) category, metastasis (M) category, residual cancer (R) category, histologic grade, or preoperative radiation therapy. In contrast to clinicopathologic parameters, p53 expression was not correlated with prognosis in univariate and multivariate survival analyses.

The p53 protein can be detected by immunohistochemistry in a high percentage of squamous cell carcinomas of the esophagus. However, the overexpression of the p53 gene product has no impact on the prognosis.