A circulating heat-resistant mucin-like antigen in patients with lung-cancer detected by a new murine monoclonal-antibody.

We discovered a circulating mucin-like antigen designated as CAM-14 detected by a new murine monoclonal antibody KL-14 (IgM). We found different heat resistant properties between serum CAM- 14 from normal individuals and from lung cancer patients. Heat treatment had less effect on the levels of CAM-14 in sera from lung cancer patients, whereas CAM-14 levels in sera from normal individuals were markedly decreased after heat treatment at tempratures > 65-degrees-C. As a serum tumor marker, CAM- 14 had only very low levels of false-positive values with a high specificity and effectively increased the positive rate for lung cancer patients when used together with carcinoembryonic antigen.