Aim: To compare the clinicopathological characteristics of human epidermal growth factor receptor 2 (HER2)-positive and HER2-negative Barrett's adenocarcinoma in Japan.
Methods: We performed immunohistochemical analysis of HER2 in 30 samples taken from patients with Barrett's adenocarcinoma and dual color in situ hybridization in cases showing 2+ reactions. We compared the clinicopathological characteristics of HER2-positive and HER2-negative patients.
Results: HER2 positivity was identified in 8 (27%) carcinoma samples. We found that HER2 expression was associated with p53 overexpression (100% vs 52.6% in pT1 tumor; 100% vs 54.5% in all stage tumor, P < 0.05) and protruding lesions at the early disease stage. There was no association between the mucin phenotype of the carcinomas and prognosis. HER2 expression and low clinical stage were unexpectedly different between Barrett's adenocarcinoma patients and gastric cancer patients, but the macroscopic features may be associated with earlier diagnosis in these patients.
Conclusion: Our results suggest that HER2-positive Barrett's adenocarcinomas are associated with p53 overexpression and lesion protrusion at the early disease stage.
Keywords: Barrett’s adenocarcinoma; Human epidermal growth factor receptor 2; Mucin phenotype; p53.