Receiver operating characteristic (ROC) curve modeling the probability of colorectal cancer detection by CEA, TFRC and CA242. Data from colorectal cancer stage TNM I-II versus matched controls were included in the statistical calculation (n = 72). The x axis is 1-specificity and the y axis is sensitivity. The red line represents the combination of all three markers with maximum sensitivity and specificity of 53% and 90%, respectively. The area under the ROC curve (AUC) signifies the accuracy of the three combined biomarkers for distinguishing colorectal cancers (TNM I-II). The area under the curve was 0.861. The dotted black line represents the point of 90% specificity.