Background and Aim: Abnormal expression of Fragile Histidine Triad (Fhit), E-cadherin and p53 is observed in esophageal squamous cell carcinoma. It has recently been reported that aberrant expression of activation-induced cytidine deaminase (AID) in gastric epithelium leads to the accumulation of nucleotide alterations in the p53 gene. However, little is known about the association between these molecular events and the clinicopathological characteristics of early stage esophageal squamous neoplasia, especially in endoscopically resected tumors.
Methods: Esophageal squamous neoplasias (n = 49) comprising nine cases of low-grade intraepithelial neoplasia (LGIN), 22 of high-grade intraepithelial neoplasia/carcinoma in situ (HGIN/CIS) and 18 of invasive cancers, were endoscopically resected. Their expression of the tumor-related proteins: Fhit, E-cadherin, p53 and AID was assessed using immunohistochemical methods, and the relationship between protein expression and clinicopathological data was examined.
Results: Reduced or absent Fhit and E-cadherin expression was detected in 22% and 0% of LGIN cases, 73% and 14% of HGIN/CIS cases, and 94% and 61% of invasive cancer cases, respectively, showing progressive increases during neoplastic progression (Fhit: P < 0.01, E-cadherin: P < 0.01). Although p53 and AID were overexpressed in these samples, no change in their expression occurred during neoplastic progression. Moreover, p53 expression was not significantly associated with AID expression.
Conclusions: These results indicate that a decrease in Fhit and E-cadherin expression could be related to the development and progression of esophageal squamous neoplasia, and that the expression of p53 was independent of aberrant AID expression in the early stage of esophageal carcinogenesis.