Nucleolin and nucleophosmin expression patterns in pulmonary adenocarcinoma invading the pleura and in pleural malignant mesothelioma

Abstract

Background Visceral pleural invasion (VPI) in adenocarcinoma of the lung is considered a poor prognostic factor. The purpose of this study was to analyze nucleolin and nucleophosmin expression in pulmonary adenocarcinoma (PA) with VPI and in pleural malignant mesothelioma. Methods The study was conducted on the basis of 19 pathologically‐confirmed cases of adenocarcinoma of the lung and 29 cases of epithelioid malignant mesothelioma. The nucleolin and nucleophosmin expression was assessed immunohistochemically and analyzed with image analysis software. Results Nucleolin expression was lower while nucleophosmin was higher in pleural invasion of pulmonary adenocarcinoma than in the central part of the tumor. Differences in subpopulations of cells with different expression of proteins studied were also found. Malignant mesothelioma showed lower nucleolin expression than adenocarcinoma of the lung but no differences in nucleophosmin expression were found. Conclusions The results of our study suggested that lower nucleolin and higher nucleophosmin expression may be related to higher invasiveness of adenocarcinoma of the lung. Differences in nucleolin expression between pulmonary adenocarcinoma and malignant mesothelioma indicate another aspect of biology of these pleura‐invading cancers that requires further study. Key points Significant findings of the study Differences in nucleolin and nucleophosmin expression in pleura invading pulmonary adenocarcinoma indicate the involvement of these proteins in its locoregional spread while differences in nucleolin expression between pulmonary adenocarcinoma and malignant mesothelioma suggest another aspect of biology of these cancers. What this study adds This is the first study on nucleolin and nucleophosmin expression in pleural malignant mesothelioma and pleura‐invading pulmonary adenocarcinoma. Our findings may assist in understanding the mechanisms of locoregional spread of adenocarcinoma and differences between these two pleura‐invading cancers.

Malignant mesothelioma: Cytological features

“…The shape of the nucleus of a mesothelioma cell is oval or ovoid, and it is positioned in the center or laterally [13]. Nuclear findings showing prominent pleomorphism suggest carcinoma, whereas a scant pleomorphism condition requires discrimination from reactive mesothelial cells [14]. Chromatin of reactive mesothelial cells tends to be less than that of carcinoma cells, though malignant mesothelial cells show distinctive features, such as hyperchromatism and coarse chromatin clumping of nuclei, prominent nucleoli, multinucleation, and marked variations in cell size [15].…”