manuscript type: original article Title: The Levels and positive rates of CEA, CA15-3 and CA 125 are Associated with Age in Chinese female Population

Background: : CEA, CA15-3, and CA125 stand out as the most commonly employed biomarkers for breast cancer. However, their clinical utility is constrained by low sensitivity and specificity. Methods: : We conducted an analysis of the levels and positive rates of Carcinoembryonic Antigen (CEA), CA 15-3 Antigen (CA 15-3), and CA 125 Antigen(CA 125) in the general female population of China. The aim was to enhance the understanding of the clinical utility of these tests. This study involved 25,785 apparently healthy female individuals and 5,146 patients diagnosed with breast cancer. Results: : The levels of CEA increased with age in both apparently healthy females and breast cancer patients. The positive rate of CEA sharply rose in generally healthy women over 40 years. In contrast, the concentration of CA15-3 remained stable in the general female individuals, and seropositivity was low among breast cancer patients. Furthermore, the serum level of CA125 exhibited a decline with age until 60 years, after which it gradually increased with advancing age. Conclusions: : Our data indicates a positive correlation between the serum level of CEA and the age of females, especially in those aged 40 and older. The concentration of CA15-3 remains stable in the general female individuals, while seropositivity is notably low in breast cancer patients. Additionally, the serum level of CA125 exhibits a V-shaped curve in women.