Tumor-associated carbohydrate antigens in primary pulmonary adenocarcinomas and their metastases

To better understand the metastatic behavior of pulmonary adenocarcinoma, we studied the differences in carbohydrate antigens between primary tumors and their metastases using three monoclonal antibodies (FH-2 defining Lewis [Le]x, AH-6 defining Le(y), and FH-6 defining sialyl Le(x-i)) on 56 autopsy cases (including 15 cases in which primary tumors were surgically resected) and 116 cases of surgically resected pulmonary adenocarcinoma. Metastatic lesions were divided into two groups according to the route of metastasis: group 1 comprised lymphatic metastases, such as lymph node and contralateral lung metastases, and group 2 comprised hematogenous metastases, such as extrathoracic spread. Both primary tumors and metastatic lesions with well-differentiated glandular patterns showed higher positive rates for Le(y) than the poorly differentiated lesions. Such a difference in the antigen expression in relation to tumor differentiation was barely demonstrated for Le(x) and sialyl Le(x-i). Discordance in antigen expression between primary and metastatic lesions (ie, positive primary tumors with negative metastatic lesions and negative primary tumors with positive metastatic lesions) was observed in the following order of frequency: extrathoracic metastatic lesion, contralateral lung, mediastinal lymph node (N2), and ipsilateral peribronchial and hilar (N1) lymph nodes. This study revealed increased biologic diversity of pulmonary adenocarcinoma in cell surface antigens following tumor progression, especially in extrathoracic metastasis.