Diagnostic value of HMGAs, p53 and β-catenin in discriminating adenocarcinoma from adenoma or reactive atypia in ampulla and common bile duct biopsies.

AIMS

Biopsies from the ampulla of Vater and the common bile duct often pose diagnostic challenges. The aim of this study was to investigate the expression patterns of HMGA1, HMGA2, β-catenin and p53 in biopsy specimens, in order to evaluate the potential diagnostic value of these proteins in differentiating adenocarcinoma from reactive atypia or adenoma.

METHODS AND RESULTS

Forty-eight biopsies (10 from the common bile duct and 38 from the ampulla) were selected for immunohistochemical studies; they included 14 cases of reactive atypia, 12 adenomas, and 22 adenocarcinomas. Expression of HMGA1 was seen in 21% of the reactive atypia cases, 42% of adenomas, and 91% of adenocarcinomas. HMGA2 was positive in 14% of reactive atypias, 42% of adenomas, and 86% of adenocarcinomas. The staining intensity of HMGA1 and HMGA2 was also significantly higher in adenocarcinomas than in adenomas or reactive atypias. Interestingly, coexpression of HMGA1 and HMGA2 was found in 86% of adenocarcinomas, 0% of reactive atypias, and 8% of adenomas. p53 and β-catenin expression seemed not to provide additional value for discriminating adenocarcinoma from reactive atypia or adenoma.

CONCLUSIONS

HMGA1 and HMGA2 might serve to discriminate between reactive atypia, adenoma and adenocarcinoma in ampulla and common bile duct biopsies.