GNRH2 and breast cancer: We showed the proof-of-principle of an antitumor therapy by using the GnRH-II antagonist [Ac-D2Nal1, D-4Cpa2, D-3Pal3,6, Leu8, D-Ala10]GnRH-II in vivo in nude mice bearing subcutaneous xenografts of human breast cancers.