ESR1 and breast cancer: Efforts to replicate these effects in metastatic breast cancer patients have been unsuccessful to date in larger samples using the same SET intervention protocol (Goodwin et al. 2001, Spiegel et al. 2007), though subgroups of patients with a poorer prognosis (those with estrogen receptor–negative disease) have shown improved survival with SET (Spiegel et al. 2007).