Phenotypic characterization of lung cancers in fine needle aspiration biopsies using monoclonal antibody B72.3

Monoclonal antibody B72.3, reactive with a high-molecular-weight glycoprotein tumor-associated antigen (designated TAG-72), has been previously shown to be reactive with formalin-fixed paraffin-embedded tissue sections of adenocarcinomas of the ovary, colon, and breast and not a variety of normal adult tissues. It has demonstrated utility as an immunocytochemical adjunct to diagnose carcinoma in cell block and cytocentrifuge preparations of human serous effusions, with selective reactivity for tumor cells (particularly adenocarcinoma) over reactive mesothelium. In this study, fine needle aspiration biopsies of 127 lung cancers (93 primary and 34 metastatic tumors) as well as 18 benign lung lesions were analyzed with monoclonal antibody B72.3 using avidin-biotin-peroxidase techniques. Monoclonal antibody B72.3 showed reactivity with 100% of the 27 lung adenocarcinomas and adenosquamous carcinomas, with greater than or equal to 10% of tumor cells showing reactivity in 22 of 27. A lesser percentage of squamous cell carcinomas (24 of 31) and large cell carcinomas (7 of 13) were immunoreactive, and of these several were weakly reactive with less than or equal to 1% tumor cells reacting. In contrast, monoclonal antibody B72.3 failed to react with any of the 21 small cell carcinomas or one carcinoid tumor evaluated. In 35 patients tumor-bearing tissue was resected, and formalin-fixed tissue sections were also evaluated. The staining pattern and percentage of tumor cells positive in the aspiration biopsies were, in most cases, highly predictive of the reactivity observed in corresponding resected tumor. Metastatic adenocarcinomas to lung from various body sites were also immunoreactive with monoclonal antibody B72.3; however, a variety of other tumor types (including 13 melanomas) failed to stain. Staining by monoclonal antibody B72.3 was not noted in any of the 18 benign lesions aspirated, with the exception of occasional fine stippling in the cytoplasm of bronchial epithelial cells. Hence, monoclonal antibody B72.3 and fine needle aspiration biopsy techniques may be of potential use in the differential diagnosis and antigenic phenotyping of a spectrum of lung neoplasms prior to surgical resection.