Herein, we describe the possible critical changes in VEGF-A, TGF-β1, ANG1, ANG2, and HIF-1α in ectopic endometriosis (with elevated pro-angiogenic factors in all studied fields), in ovarian endometrioid adenocarcinoma (showing typical upregulation on the TGF-β1 axis), and two different types of endometrial carcinoma (with an extreme pathological ANG2/ANG1 axis for mixed mesodermal tumors). The gene discussed is HIF1A; the disease is ovarian endometrioid adenocarcinoma.