Immunohistochemical expression of p63 in esophageal Barrett's adenocarcinoma.

p63, which has recently been identified as a member of the p53 gene family, plays many important roles in human tissue functions. We examined p63 expression patterns in esophageal Barrett's adenocarcinoma, including early-stage cancers, as well as its clinicopathological significance. Immunoreactivity for p63 was detected in 45.8% (11/24) of the adenocarcinomas; all cases were focally positive. p63 was detected not only in the in situ carcinomatous components or intramucosal carcinomas, but also in the invasive carcinomatous regions of the p63-positive cases. Immunohistochemical expression was correlated with clinicopathological features; i.e., lymph node metastasis, lymphatic invasion and venous invasion were found in 72.7% (p<0.01), 100% (p<0.05) and 90.9% (p<0.05) of the p63-positive cases, respectively, at a significantly high incidence compared with the p63-negative cases. We also analyzed the relationship between p63 and p53 expression. No diffuse expression of p63 was detected, although diffuse expression of p53 was detected in 50.0% (12/24) of the adenocarcinomas. The role of the p63 gene is thought to be different in esophageal Barrett's adenocarcinoma compared with esophageal squamous cell carcinoma. p63 immunoreactivity was most useful as a predictor of lymph node metastasis.