The objectives were to (1) characterize the expression of RGS10 in freshly resected breast cancer and adjacent normal breast tissues; (2) determine the prognostic significance of RGS10 expression in patients with breast cancer; and (3) explore the role of RGS10 and upstream effectors in tumor progression and metastasis in breast cancer cells in vitro and in vivo. Here, RGS10 is linked to breast carcinoma.