According to the ROC curve (figure 1), serum CEACAM1 cutoff value ≥ 2.22 ng/ml can be used as a cutoff point at which 93.3% of breast cancer patients (T1 and T2 stages) can be early diagnosed correctly, but 17.5% of normal subjects are false positive. This evidence concerns the gene CEACAM1 and breast carcinoma.