Migratory gene expression signature predicts poor patient outcome: are cancer stem cells to blame?

Breast cancer metastasis accounts for the majority of deaths from this disease. In the previous issue of Breast Cancer Research, Patsialou and colleagues used a novel in vivo invasion assay to capture migrating breast cancer cells and demonstrate that the gene expression signature of these cells predicts breast cancer metastasis in a large cohort of patients. Furthermore, specific genes identified play a functional role in the invasion of MDA-MB-231 breast cancer cells and in patient-derived breast tumors. These genes regulate pathways known to be induced in invasion and metastases and play an important role in the regulation of cancer stem cells.