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

Abstract

Aims: Human chorionic gonadotropin (hCG) beta in serum is a promising tumour marker for gastrointestinal malignancies. Our aim was to investigate the expression of hCGbeta by immunohistochemistry in various gastrointestinal cancers and benign tissues.

Methods and results: A monoclonal antibody (MAb) specific for free hCGbeta was used to stain 107 tissue samples from various gastrointestinal malignancies and 36 benign or normal tissue samples. The specificity of the staining was verified and the results compared with those obtained with a widely used commercial polyclonal antibody (PAb) which reacts with both free hCGbeta 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 frequently. We also discovered immunoreactivity in half of the non-malignant samples from pancreatic and biliary tissues. With the PAb, hCG immunoreactivity was evident more frequently in some cancers, but the staining was diffuse and occasionally polymorphonuclear leucocytes were strongly stained.

Conclusions: This study shows that our MAbs specific for hCGbeta are well suited for immunohistochemistry. Our results confirm previous findings on gastrointestinal cancers and, furthermore, we demonstrate hCGbeta tissue expression in pancreatic adenocarcinoma. The results support reports on hCGbeta as a serum tumour marker for digestive tract diseases.