Normally, the CEA level in saliva was 67.8 [59.6; 94.6] ng/mL, CEA content increases by 1.37 times in fibroadenomas (160.7 [139.2; 199.4] ng/mL) and by 1.79 times in breast cancer (189.2 [141.3; 215.4] ng/mL) (Figure 1A). Here, CEACAM5 is linked to breast cancer.