Quantitative analysis of carcinoembryonic antigen, squamous cell carcinoma antigen, CA 125, and CA 50 cytosolic content in non-small cell lung cancer.

Background. The cytosolic content of carcinoembryonic antigen (CEA), squamous cell carcinoma (SCC), CA 125, and CA 50 antigens in non-small cell lung cancer (NSCLC) is analyzed in this study. The aim was to ascertain the relationship between tumor marker content and the clinicopathologic aspects of this neoplasm. Methods. Lung tissue samples were obtained at the time of surgery from 75 patients with NSCLC patients (samples of tumor and unaffected tissue) and 29 subjects with idiopathic pneumothorax. All determinations were performed on cytosols obtained from lung specimens. CEA and CA 125 were determined by enzyme immunoassay, SCC antigen by radioimmunoassay, and CA 50 by fluoroimmunoassay. Tumor marker content was analyzed by TNM stage, histologic type, tumor grade, and number of atypias. Results. The concentration of the four markers was significantly higher in cytosol obtained from neoplastic tissue. Frequency of elevated levels of CEA was higher in adenocarcinoma (87% cases expressing high levels of the marker), SCC antigen in epidermoid carcinoma (65% expressing high levels), and CA 125 in large cell carcinomas (100% expressing high levels). No association was found between TNM stage and cytosol concentration for any of the four markers. CEA exhibited significantly greater concentration in well differentiated tumors, whereas this was true of CA 125 in poorly differentiated tumors. CA 125 content was higher in tumors with more atypia. Conclusions. Cytosolic quantification of tumor markers may be an adjuvant mechanism to evaluate histologic subtypes of non-small cell lung cancer and identification of tumors with poorly differentiated features.