Cell cycle inhibitory protein p27 in esophageal squamous cell carcinoma.

ABSTRACT

BACKGROUND: p27 protein is one of the cdk inhibitors which regulates the progression from G1 to S phase of the cell cycle. Reduced expression of p27 protein has been reported to be correlated with poor clinical outcome in patients with various cancers. MATERIALS AND METHODS: We performed immunohistochemistry of both p27 and Ki67 in 136 cases of resected human esophageal squamous cell carcinoma, and evaluated the association between p27 immunoreactivity and clinicopathological features including clinical outcome in these patients. We also examined the correlation between labeling index or the percentage of positive tumor cells for p27 and Ki67 in serial tissue sections in these cases. RESULTS: Cases with invasion of the muscularis propria or adventitia had significantly (p < 0.05) higher p27 LI (65.0 +/- 23.7) than those with invasion limited to mucosa or submucosa and those with carcinoma in situ (58.9 +/- 18.3). There were no significant correlations between p27 and other clinicopathological factors such as sex, age, tumor size, differentiation type, nodal status and histological stage. The cases with p27 LI below 40% tended to have a worse prognosis than those with p27 LI above 40%. There was no significant correlation between Ki67 and p27 LIs. CONCLUSIONS: Reduced expression of p27 may be correlated with the biological behavior of esophageal squamous cell carcinoma and may play an important role in the early stages of cancer.