[Immunohistochemical findings in resected lung cancer]

The relationship between histological type and immunohistological findings was studied in total 141 cases of resected lung cancer. Adenocarcinoma was cytologically subtyped according to the ultrastructural findings. Immunohistochemical staining was performed on paraffin-embedding tissue using the avidin-biotin-peroxidase complex method for carcinoembryonic antigen (CEA), keratin, secretory component (SC), neuron specific enolase (NSE), lysozyme (Ly) and lactoferrin (La). Adenocarcinoma stained strongly positive with antibody against CEA and SC. There was no statistical difference among the different subtypes of adenocarcinoma, but in the cases of clara cell type, CEA staining was less intense and in goblet cell type, the intensity of SC staining was great. Goblet cell type characteristically stained positively with anti-Ly antibody, and Ly was a specific marker for differentiating adenocarcinoma of goblet cell type. La was positive not only in bronchial gland cell type, but also in other subtypes in adenocarcinoma. Squamous cell carcinoma showed more intense staining with anti-keratin antibody than other histological types. Small cell carcinoma extensively stained with anti-NSE antibody, but some of the other histological types also stained positively. NSE was a relatively good marker for small cell carcinoma but was not specific. It is concluded that immunohistochemical examination is a useful method for differentiation of different histological types of lung cancer.