Extranuclear functions of ER impact invasive migration and metastasis by breast cancer cells.

The molecular basis of breast cancer progression to metastasis and the role of estrogen receptor (ER) signaling in this process remain poorly understood. Emerging evidence suggests that ER participates in extranuclear signaling in addition to genomic functions. Recent studies identified proline-, glutamic acid-, and leucine-rich protein-1 (PELP1) as one of the components of ER signalosome in the cytoplasm.