As depicted in Figure 4, increased serum levels of Trx1 and CEA were detected in breast cancer patients, but the increase of CEA levels (10%, from 7.731 ± 1.051 to 8.525 ± 1.282 ng/mL: mean ± SD) was significantly lower than that of Trx1 levels (56.8%, from 25.59 ± 4.211 to 40.12 ± 6.816 ng/mL: mean ± SD) compared to their values of corresponding female normal controls. This evidence concerns the gene CEACAM5 and breast cancer.