KRAS and colorectal carcinoma: Subsequently, the four indicators were combined to evaluate AUC value from the ROC curve, and the result showed AUC value was 0.920 (Confidence Interval: 0.880-0.960), making no evident alteration comparing to the model established with KRAS, M3 and Methylation combination, indicating that FIT might make no significant contribution to diagnosis performance when KRAS, M3 and Methylation were used to predict CRC (Figure 5A); The combination of four indicators showed the highest AUC value 0.931 in early CRC and 0.886 in advanced CRC (Figures 5B, C).