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[Immunohistochemistry in pancreatic cancer with new monoclonal antibodies]
Abstract:
Immunhistochemistry using hybridoma-derived monoclonal antibodies (MAb's) directed against tumor associated antigens offers new approaches to morphological diagnosis of tumors, e.g. for classification and typing of tumor subtypes with different prognosis. Before in-vivo application of monoclonal antibodies in man for diagnostic or therapeutic purposes the tissue distribution of the antibody should be determined immunhistochemically for assessment of antibody sensitivity and specificity. The binding capacity of the newly developed MAb BW 494/32 to pancreatic cancer tissues was therefore tested by immunhistochemistry, other benign and malignant intestinal and extraintestinal tissues served as controls. The MAb BW 494/32 showed positive immunoreactivity in all cases of ductal pancreatic adenocarcinomas grading I to II (sensitivity: 100%). In grading III carcinomas the target antigen was only accessible in half of the tested specimens. Specificity was limited by a mostly weak immunoreactivity with normal pancreas tissue in 36%, with acute inflamed tissue in 100%, with inflamed tissue in chronic pancreatitis in 71%. Extrapancreatic specificity was restricted by positive antibody binding to singular goblet cells of gastrointestinal epithelium. The well established antibody CA 19-9 was used for comparison. CA 19-9 showed about the same sensitivity of 88% (BW 494/32: 92%) for ductal pancreatic adenocarcinomas grading I to III. Specificity of CA 19-9, however, was comparable more restricted, as CA 19-9 showed a significant cross-reactivity with other gastrointestinal adenocarcinomas (5 out of 6 colorectal cancers, 3/6 gastric carcinomas, 1/3 carcinomas of the common bile duct), with some extraintestinal cancers (breast 60%, lungs 50%) and with other non-cancerous tissues of intestinal origin. According to the results of this study it is worthwhile to investigate the antibody BW 494/32 for possible applications in experimental immunodiagnosis and -therapy of pancreatic cancer.