Heterogeneous nuclear ribonucleoprotein B1 (
hnRNP B1), an
RNA binding protein, is a useful marker for early detection of lung
squamous cell carcinoma because it is overexpressed in the early stages of
lung cancer, including bronchial dysplasia, a premalignant lesion of lung
squamous cell carcinoma. In the case of
adenocarcinoma, we investigated the utility of
hnRNP B1 for both detection of early
adenocarcinoma and discrimination of non-invasive lesion, atypical adenomatous
hyperplasia (AAH) from
adenocarcinoma.
hnRNP B1,
cyclin D1, p16, and Ki-67 were analyzed in
lung adenocarcinoma tissues and divided into early and overt
adenocarcinoma and AAH, using immunohistochemistry. The intensity of these molecular markers was compared among three groups and also analyzed for 4 patients who showed both
adenocarcinoma and AAH. Thirty-six of 54 (67%)
adenocarcinoma patients showed positive staining of
hnRNP B1: 14/20 (70%) early
adenocarcinoma and 22/34 (65%) overt
adenocarcinoma. In contrast, overexpression of
hnRNP B1 in non-invasive lesion, AAH was observed in only 9% (1/11). Overexpression of
cyclin D1 and decrease of p16 were frequently observed in both
adenocarcinoma and AAH. These results suggest that
hnRNP B1 would be a candidate of molecular marker for detection of early
lung adenocarcinoma. In addition, combined analysis of
hnRNP B1 and cell cycle-related genes, such as
cyclin D1 and p16, might aid in discrimination of AAH from early
adenocarcinoma.