A cell kinetic study of pulmonary adenocarcinoma by an immunoperoxidase procedure after bromodeoxyuridine labeling

By in vitro labeling with bromodeoxyuridine (BrdU) and immunohistochemical staining with anti-BrdU monoclonal antibody, the tumor cell kinetics were investigated in 52 resected pulmonary adenocarcinomas. The values of the BrdU labeling index (LI) varied widely among cases of adenocarcinoma in comparison with four cases of small cell carcinoma and ten cases of squamous cell carcinoma examined as controls. The LI was below 3.0 in 60% of the adenocarcinomas. When the LI was analyzed according to the cytologic subtypes of adenocarcinoma, the values were low for goblet cell type and type II alveolar cell type, whereas the values for the bronchial surface epithelial cell type varied widely (average, 5.2) and those for the Clara cell type were intermediate (average, 1.8). A comparison of the LI with TNM classification, histologic differentiation, degree of nuclear atypia, and mitotic cell count showed a correlation between the LI and each of these prognostic factors. Thus, the possibility of the BrdU LI being a useful new prognostic factor of pulmonary adenocarcinomas was suggested.