Comparative studies of CAM 123-6 and carcinoembryonic antigen for the serological detection of pulmonary adenocarcinoma.

Carcinoembryonic antigen (CEA) has been clinically used as a serum marker for lung cancer, especially for pulmonary adenocarcinoma. Since we had developed a tumor marker against pulmonary adenocarcinoma, CAM 123-6 belonging to KL-6 MUC 1 mucin, we compared its clinical value with that of CEA, in combination with squamous cell carcinoma-related antigen (SCC) and neuron-specific enolase (NSE). The subjects were 30 patients with adenocarcinoma, 23 with squamous cell carcinoma, 16 with small cell carcinoma, and 20 with benign lung disease. For discriminating lung cancer from benign lung disease, the combination of CAM 123-6, SCC, and NSE showed 64% diagnostic accuracy, and the combination of CEA, SCC, and NSE 65%. In differentiating pulmonary adenocarcinoma from other lung cancer, the diagnostic accuracy of CAM 123-6 was 81% and that of CEA was 74%, although there was no significant difference between them. These observations indicate that the diagnostic accuracy of CAM 123-6 is similar to that of CEA. Neither marker is sufficiently specific to differentiate pulmonary adenocarcinoma from other forms of lung cancer.