Can we predict and prevent specific sites of metastases in breast cancer patients?

Despite improvements in breast cancer therapies, cancer cells frequently spread to distant organs years or decades after primary tumor surgery and adjuvant treatment. This expansion, known as metastasis, can bring about fatal consequences. Traditionally, the risk of metastasis has been predicted by prognostic factors such as tumor size, axillary lymph node status and histological grade. More recently, genomic tests have also been used for this purpose. The presence of ER, PR and ERBB2 gene amplification are currently key markers in the characterization of breast tumor type that drive the selection of specific therapies. ER-positive tumors are more prone to metastasize into the bone, whereas ER-negative tumors preferentially spread to visceral organs such as lung, liver and brain. However, the reliability of these markers is limited. In this regard, substantial efforts have been made to find new markers that predict the most probable target organ of metastasis, with the aim to improve diagnosis and develop organ-specific treatments for breast cancer metastatic patients.