Encouragingly, AACT‐N106‐H7N6S4F1 performed much better than serum CEA in diagnosing early‐stage GC, with AUC values of 0.901 (95% CI, 0.837‐0.964) versus 0.543 (95% CI, 0.398‐0.689) and sensitivities of 87.5% versus 29.2% under the same specificity of 80% (Figure 4f). Here, CEACAM5 is linked to gastric cancer.