HER-2/Neu expression as a progression marker in pancreatic intraepithelial neoplasia

Pancreatic intraepithelial neoplasia is only partially defined. Any attempt to establish the diagnostic criteria of early pancreatic carcinoma has been unsuccessful so far. In the present study we investigate expression of HER-2/neu in hyperplastic pancreatic duct epithelium. Material included resected pancreatic tissue obtained from 13 patients with pancreatic carcinoma, 11 with chronic pancreatitis, and 11 patients operated on for other reasons (gastric cancer, carcinoma of papilla Vateri). Hyperplasia of pancreatic duct epithelium was scored as: 1. flat mucosal hyperplasia FH, 2. papillary hyperplasia PH, 3. atypical papillary hyperplasia APH, 4. carcinoma in situ CIS. Immunohistochemical expression of HER-2/neu was studied with the biotin-streptavidin method. Results were scored as: 1+ barely perceptible light membranous rimming, 2+ light to moderate rimming, 3+ moderate to strong rimming. Expression of HER-2/neu paralleled with the hyperplasia grading, in most cases being negative in normal duct epithelium, weak in flat hyperplasia, and moderate to strong in atypical papillary hyperplasia and carcinoma in situ. In conclusion, HER-2/neu expression could be used as an additional marker of hyperplasia, dysplasia and atypia of pancreatic ductal and ductular epithelium in the process of pancreatic epithelial neoplasia. This could be especially useful in the cytological diagnosis of pancreatic intraepithelial neoplasia.