[Morphologic, morphometric and immunohistochemical studies on pancreatic intraductal hyperplasia and infiltrating...

Pancreatic cancer belongs to the neoplasms which are characterised by increasing morbidity and mortality. Five-year survival rates of about 0.4% are the norm, and little has changed in the last 70 years. Important etiological factors are age, sex, diet, tobacco smoking, alcohol abuse, occupation and chemical exposure, hereditary chronic pancreatitis, and previous surgery (cholecystectomy and gastrectomy). The majority of exocrine tumours of the pancreas are malignant and 80-90% of them comprise ductal adenocarcinomas. The development and growth of pancreatic carcinoma appears to be caused by a progressive accumulation of multiple genetic abnormalities. This includes oncogene (K-ras) activation, loss of tumour-suppressor p53 gene function and overexpression of growth factors and their ligands. The morphological background for the development of pancreatic carcinoma is ductal epithelial hyperplasia. Current molecular studies have resulted in the identification of cell clones exhibiting the same genetic alterations (K-ras and p53 mutations) as in infiltrating pancreatic carcinoma. Pancreatic intraepithelial neoplasia is only partially defined. The purpose of our study was to evaluate Ki-67 proliferative index and HER-2/neu gene expression in pancreatic intraepithelial proliferative lesions as a sign of increasing epithelial proliferation and dysplasia. Additionally we made an attempt to apply morphometry in demarcating between intraepithelial proliferations of "reactive" type and proliferations with tendency towards progression to cancer. Another aim of the study was to evaluate the expression of bcl-2 and p53 genes in various types of pancreatic intraepithelial proliferations and in pancreatic cancer and to answer the question whether they interact in the process of pancreatic intraepithelial neoplasia. We have also undertaken investigations aiming at determination of the CD44s gene and its v6 isoform expression in intraductal and invasive pancreatic carcinoma, attempting to correlate this expression with the p53 gene mutations. The results of our study indicate that intraductal pancreatic proliferations form a group of heterogeneous lesions possessing different proliferative activity of cells, karyometric features and HER-2/neu, bcl-2 and p53 genes expression. The precancerous lesion in the pancreas may be atypical papillary hyperplasia, which is similar to intraductal carcinoma with respect to the proliferative activity of cells and HER-2/neu, bcl-2 and p53 expression. Pancreatic carcinoma is characterised by high p53, CD44s and CD44v6 expression and low bcl-2 expression. CD44 and p53 genes expression is independent and between bcl-2 and p53 expression there is an inverse correlation. The p53 and CD44v6 expression is the higher the lower is the histological grade of the pancreatic carcinoma.