IMMUNOHISTOCHEMICAL AND MOLECULAR BIOLOGICAL STUDIES OF SEROUS CYSTADENOMA OF THE PANCREAS

Seven cases of pancreatic serous cystadenoma were examined immunohisto chemically and molecular biologically. Six were benign tumors and one was clinically malignant. Immunohistochemical studies were performed w ith the avidin-biotin peroxidase complex technique on paraffin embedde d tumor tissue and were stained with antibody to carcinoembryonic anti gen (CEA), CA19-9, and p53 protein. Two-stage polymerase chain reactio n-restriction fragment length polymorphism analysis was used to detect K-ras oncogene mutation at codon 12. No tumor cells were stained with anti-CEA and anti-p53 protein, but two cases were stained focally wit h anti-CA19-9. One case was benign and one was clinically malignant. I n the anti-CA19-9 staining, tumor cells of the benign case were positi ve only on the apical membrane and supranuclear cytoplasm of the cells , whereas those of the clinically malignant case were positive over th e entire surface and cytoplasm of the cells. All seven cases were with out K-ras gene mutation. So the features of serous cystadenoma of the pancreas suggest a tumor genesis different from that of ductal adenoca rcinoma. They also suggest a relationship between immunohistochemical localizations of CA19-9 in the tumor cells and the biological behavior of the tumor itself.