ESR1 and cancer: Taken together, it can be postulated that 1) ERRα is a possible therapeutic target for both ER+ and ER- cancers; 2) Grailsine-Al-glycoside is a natural anticancer agent that may be able to inhibit ER, ERRα, and other signaling pathways; 3) the response to Grailsine-Al-glycoside varies among cancers due to different signaling composition.