The superiority of mammaglobin-1 in differentiating LN positive from LN negative tumors as well as metastatic from non-metastatic lesions compared to CA15-3 clearly highlights the possible use of BM mammaglobin-1 immunoreactivity as well as gene expression levels as an ideal marker for early detection of BM micrometastases in BC. Here, SCGB2A2 is linked to breast cancer.