Objective: To investigate the role of AIB1 gene in the development of esophageal squamous cell carcinoma (ESCC) and its clinicopathologic significance.
Methods: Two tissue microarrays, including 203 cases of ESCC, were prepared. Fluorescence in-situ hybridization (FISH) and immunohistochemistry were performed to detect the amplification of AIB1 gene and expression of its encoded protein in ESCC. The results were correlated with various clinicopathologic parameters.
Results: In the 203 cases of ESCC studied, FISH was successful in 115 cases. Amongst those, amplification/gain of AIB1 gene was observed in 15 cases, including high-level amplification in 5 cases (4.3%) and low-level gain in 10 cases (8.7%). As for immunohistochemical study, AIB1 protein was overexpressed in 94 cases of ESCC. There was a significant association of AIB1 overexpression and tumor staging. AIB1 was overexpressed in 66 of the 123 cases in advanced T stages (T3 to 4), compared with 25 of the 80 cases in early T stages (P = 0.008). Those cases with high-level amplification of AIB1 also showed overexpression of its encoded protein. On the other hand, 8 of the 10 cases with low-level gain of AIB1 showed protein overexpression. The remaining 41 of the 100 cases which did not have AIB1 gene amplification/gain demonstrated overexpression of AIB1 protein.
Conclusion: Overexpression of AIB1 protein caused by gene amplification/gain or other molecular mechanisms may play an important role in the development and/or progression of a subset of ESCC.