Thus GHRH antagonist MZ-5-156 at doses of 0.1 and 1 μM reduced the proliferation of T47D, MDA-MB-468, MDA-MB-435s, LNCaP and NCI H838 cancer cell lines by 30–35, 28–34, 33–40, 30–37, and 30–36% respectively. This evidence concerns the gene GHRH and cancer.