Because GnRH agonists antagonize EGF-induced cell growth and c-fos gene expression through the Ras/MAPK pathway, we have analyzed whether E2-induced activation of SRE and expression of c-fos in ERα-positive human breast, endometrial, and ovarian tumor cells is also inhibited by GnRH agonists and whether GnRH reduces E2-induced cell proliferation (1). The gene discussed is FOS; the disease is ovarian neoplasm.