Specific staining of human chorionic gonadotropin beta in benign and malignant gastrointestinal tissues with monoclonal antibodies

Aims:Human chorionic gonadotropin (hCG) beta in serum is a promising tumour marker for gastrointestinal malignancies, Our aim was to investigate the e xpression of hCG beta by immunohistochemistry in various gastrointestinal c ancers and benign tissues. Methods and results: A monoclonal antibody (MAb) specific for free hCG beta was used to stain 107 tissue samples from various gastrointestinal maligna ncies and 36 benign or normal tissue samples, The specificity of the staini ng was verified and the results compared with those obtained with a widely used commercial polyclonal antibody (PAb) which reacts with both free hCG b eta and intact hCG, as well as with luteinizing hormone beta. With the MAb, we observed positive immunohistochemical staining in 24% of the malignant gastrointestinal tumours. Gastric (60%) and pancreatic (56%) carcinomas, as well as extrahepatic cholangiocarcinomas (36%), were positive most frequen tly, We also discovered immunoreactivity in half of the non-malignant sampl es from pancreatic and biliary tissues, With the PAb, hCG immunoreactivity was evident more frequently in some cancers, but the staining was diffuse a nd occasionally polymorphonuclear leucocytes were strongly stained. Conclusions: This study shows that our MAbs specific for hCG beta are well suited for immunohistochemistry, Our results confirm previous findings on g astrointestinal cancers and, furthermore, we demonstrate hCG beta tissue ex pression in pancreatic adenocarcinoma. The results support reports on hCG b eta as a serum tumour marker for digestive tract diseases.