Abstract
Normal tissues and cancers of the lung were examined immunohistochemically for distribution of secretory component (SC) and lactoferrin (LF), using anti-SC and anti-LF immunoglobulin. In the normal lung, SC was present in bronchial ciliated columnar epithelial cells and bronchial gland serous cells and almost all was in bronchial gland serous cells. In terms of histologic type, SC was detected in over 70% of adenocarcinoma cases, and some large cell carcinoma, small cell carcinoma and peripheral squamouscell carcinoma cases. LF was mainly detected in bronchial gland cell type adenocarcinoma cases, and to lesser degrees in other subtypes of adenocarcinoma, large cell carcinoma and small cell carcinoma cases. In these studies, which incidentally demonstrated that LF is a good marker of the bronchial gland cell type adenocarcinoma, the author concluded that not only adenocarcinoma but also large cell carcinoma, small cell carcinoma and squamous cell carcinoma show some degree of differentiation to bronchial epithelial cells or bronchial gland cells. It is therefore possible that these four histologic types of lung cancer are not completely independent entities and may possess common histogenetic characteristics.
