Abstract: Objective  To establish an indirect sandwich enzyme-linked immunesorbent assay (ELISA) kit for detecting serum level of mucin 1(MUC1) protein and to
explore its application in diagnosis of lung cancer,and to reveal the value of MUC1 protein  detection in clinic.Methods With rabbit anti-human MUC1 monoclonal antibodies and rat anti-MUC1 polyclonal antibodies as coating antibodies and testing antibodies,respectively,a new ELISA method was developed in this study,and the standard curve was gotten.Then,the serum MUC1 levels in the peripheral blood of 48 cases with lung cancer,7 cases with lung benign diseases,and 20 healthy subjects were detected with indirect ELISA.The optimal cut-off value,the specificity,the sensitivity and the Youden index were determined with ROC curve analysis.At the same time,the serum levels of MUC1 detected by CA15-3 commercial kits were analyzed.
Results Based on indirect sandwich ELISA,the cut-off value for serum MUC1 was 1.98  μg?L-1,the sensitivity was 62.5%,the specific
ity was 100% and the Youden index was 0.6250.While based on the CA15-3 kit,the sensitivity was 18.75%,the specificity was 100% and the Youden index was 0.187 5.Conclusion The indirect ELISA kit is superior to the CA15-3 kit in detecting MUC1 in lung cancer .

Key words:  , mucin 1, anti-MUC1 polyclonal antibody, enzyme-linked immunesorbent assay, lung neoplasms