Table-I. ROC curve analysis showed that CEA, CA125 and SP70 antigen in pleural effusion were all valuable in diagnosing NSCLC combined with malignant pleural effusion (p<0.05). At this time, CEA had an AUC of 0.768, sensitivity of 85.71%, specificity of 67.86%, accuracy of 76.79% and kappa value of 0.536; CA125 had an AUC of 0.750, sensitivity of 80.36%, specificity of 69.64%, accuracy of 75.00% and kappa value of 0.500; SP70 antigen had an AUC of 0.804, sensitivity of 71.43%, specificity of 89.29%, accuracy of 80.36% and kappa value of 0.607, Table-II and Fig.1. Here, CEACAM5 is linked to Pleural effusion.