CEACAM5 and gastric cancer: After combining serum tRF-17-18VBY9M with any of the serum markers of CEA, CA 199 and CA 724’s AUC and SEN were further improved and reached a maximum after the combination of the four biomarkers, which was consistent with the previous results (Fig. 5D–F; Table 4), suggesting that tRF-17-18VBY9M could be able to differentiate GC patients from gastritis patients.