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

Abstract

Specific staining of human chorionic gonadotropin β in benign and malignant gastrointestinal tissues with monoclonal antibodies Aims: Human chorionic gonadotropin (hCG) β in serum is a promising tumour marker for gastrointestinal malignancies. Our aim was to investigate the expression of hCGβ by immunohistochemistry in various gastrointestinal cancers and benign tissues. Methods and results: A monoclonal antibody (MAb) specific for free hCGβ 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 hCGβ and intact hCG, as well as with luteinizing hormone β. 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 hCGβ are well suited for immunohistochemistry. Our results confirm previous findings on gastrointestinal cancers and, furthermore, we demonstrate hCGβ tissue expression in pancreatic adenocarcinoma. The results support reports on hCGβ as a serum tumour marker for digestive tract diseases.