Besides that, the conjugate GnRH-III-[2ΔHis, 3d-Tic, 4Lys(Bu), 8Lys(Dau=Aoa)] (10) revealed an improved inhibitory effect on the growth of both cancer cell lines, whereby the cytostatic effect on MCF-7 breast cancer cells was increased by more than one order of magnitude in comparison to K2. The gene discussed is GNRH1; the disease is breast cancer.