Immunohistochemical Demonstration of Glycoprotein 170 and Glutathione S-Transferase Isoenzymes in Normal and Neoplastic Bronchial Tissue

Abstract

Background: The aim of this study was to demonstrate the content of drug-transporting and -metabolizing enzymes in primary lung cancer. Material and Methods: We investigated 20 specimens of lobectomies, bilobectomies, pneumonectomies and extended pneumonectomies of patients suffering from lung Results: In normal bronchial tissue and various primary lung tumors, we observed a high content of glycoprotein 170 (gp 170), and glutathione S-transferase (GST) placenta (π) and liver (α) types. Gp 170 and GSTπ were localized in columnar epithelium, excretory ducts, serous glands, muscles, cartilage, nerves and vessel walls. Nine of 12 squamous cell carcinomas showed a considerable quantity of gp 170, comparable with the amount of gp 170 in the proximal tubules of the kidney. All of them stained for GST π. GST α was demonstrable to a lesser extent than GSTπ. Only few of the carcinomas stained markedly positive for GSTα. There was no correlation between the quantity in normal bronchial tissue and the corresponding tumor for any enzyme studied. Conclusions: If gp 170 and GST play a role in primary chemoresistance, expecially in multiple drug resistance, our results explain the high rate of primary chemoresistance in non-small cell lung tumors.