Antigenic heterogeneity of human lung cancers.

Antigenic reactivity of 35 perchloric acid (PCA) extracts of different histologic human lung cancer tissues was studied--in comparison with the reactivity of the carcinoembryonic antigen (CEA), the nonspecific cross-reacting antigen (NCA), and alpha-1-antichymotrypsin--with the use of specific immune sera against PCA extracts of lung squamous cell carcinoma, and anti-CEA, anti-NCA, and anti-alpha-1-antichymotrypsin sera. The following antigenic systems were found in lung cancers: a) antigens specific for most squamous cell cancers and adenocarcinomas, which are undetectable in small cell cancers; b) NCA-type antigens; c) CEA-like antigens; and d) the antigen responsible for alpha-1-antichymotrypsin reactivity. A considerable antigenic heterogeneity among lung cancers indicates the necessity for precise histopathologic verification of individual lung cancer cases before commencement of immunologic studies and purification of antigens specific for lung cancers.