Carcinoembryonic antigen (CEA), carbohydrate antigen 125 (CA125), carbohydrate antigen 15-3 (CA15-3), and carbohydrate antigen 19-9 (CA19-9), which are considered traditional circulating biomarkers for BC, are used less frequently for the early diagnosis of BC because of their low sensitivity and specificity (Wang et al., 2017; Li et al., 2019a; Nam et al., 2019; Li et al., 2020). This evidence concerns the gene CEACAM5 and breast cancer.