Ubiquitous p63 expression in human esophageal squamous cell carcinoma

p63, a recently identified member of the p53 gene family, plays an important role in human tissue functions. We examined the pattern of p63 expression in human esophageal squamous cell carcinomas including early-stage cancers, and its clinicopathological significance. Immunoreactivity for p63 was detected in 96.9% (63/65) esophageal squamous cell carcinomas. Diffuse p63 expression was seen in 75.4% (49/65). p63 was detected not only in the in situ carcinomatous components or intramucosal carcinomas, but also in the invasive carcinomatous parts of the p63-positive cases. There were no significant correlations between p63 expression and clinicopathological features, such as depth of tumor invasion, tumor differentiation, lymph node metastasis and venous/ lymphatic invasion. We also analyzed the relationship between p63 and p53 expression in esophageal squamous cell carcinomas. These results suggest that the p63 gene, as well as the p53 gene, play a major role in the carcinogenesis of human esophageal squamous cells and in the growth of the carcinoma.