The mean PCT value in sera corresponding to 41 contaminated BC was 2.67±10.44 ng/ml; in the subgroup of sera corresponding to positive SF/contaminated BC samples it was significantly higher than that of the subgroup corresponding to negative SF/contaminated BC samples (18.24±28.19 ng/ml Vs 0.62±0.89 ng/ml, respectively, p<0.0001). This evidence concerns the gene CALCA and breast cancer.