Greater sensitivity was achieved using the mean+2 SD of control PLAC1 serum values, where the false positive rate was 3% and was exceeded by 38%, 40%, 60% and 43% of subjects with DCIS, HER2+, TNBC and ER+/PR+/HER2- tumors. This evidence concerns the gene ERBB2 and ductal breast carcinoma in situ.