Differences in lectin binding of malignant pleural mesothelioma and adenocarcinoma of the lung

In order to differentiate between malignant pleural mesothelioma and adenocarcinoma of the lung, the glycoconjugate profiles of 6 reactive mesothelial lesions, 23 mesotheliomas (17 epithelial, 1 desmoplastic, 2 biphasic, and 3 fibrous types), and 28 well-differentiated pulmonary adenocarcinomas were evaluated with the use of 8 lectins in addition to anti-carcinoembryonic, anti-keratin and anti-epithelial membrane antigen. Formalin-fixed, paraffin-embedded tissues were stained with the avidin-biotin peroxidase complex method. Reactions of wheat germ (WGA) and peanut (PNA) agglutinin with neuraminidase treatment lectins were positive in 5 of 6 (83%) and 3 of 6 (50%) cases, respectively, in reactive mesothelial lesions. Thirteen of 23 (57%) malignant mesotheliomas of the pleura showed a positive reaction for WGA and PNA with neuraminidase treatment; other lectins were low-positive, below 9%. In contrast, pulmonary adenocarcinomas showed positive reactions in 27 of 28 cases (96%) for PNA, 26 of 28 (93%) for Ricinus communis (RCA-I), 25 of 28 (89%) for WGA, and 22 of 28 (79%) for succinylated WGA (SucWGA). The findings suggest that malignant pleural mesothelioma and pulmonary adenocarcinoma have consistent and distinct glycoconjugate profiles, and that stains for RCA-I and SucWGA may be useful for differential diagnosis.