Diagnostic application of a monoclonal antibody against small cell lung cancer

A monoclonal antibody (MOC-1) directed against an antigen present in small cell lung cancer (SCLC) was used for diagnostic purposes. After screening of biopsy specimens of lung tumors, MOC-1 was found to react with SCLC (n = 10) and adenocarcinoma of the lung (4 of 9 cases). Except for a few cells in a poorly differentiated tumor, the reaction with squamous cell cancer was negative (n = 6). Staining with MOC-1 by an immunoperoxidase technique on imprints of biopsy specimens procured by rigid bronchoscopy was found to be a reliable and rapid method for diagnosing SCLC (16 of 17 positive). All cytologically proven bone marrow and pleural metastases of SCLC were found by staining on a cytospin preparation with MOC-1. Moreover, in three cytologically negative cases, MOC-1-positive cells were detected.