In the Pten/Apc model, it was shown previously that both OSE cells (based on the intrabursal injection of Ad-CMV-Cre) and FTE cells (based on the tamoxifen-induced activation of Ovgp1-iCreER) could serve as the cells-of-origin of endometrioid ovarian cancer [26,32]. The gene discussed is PTEN; the disease is ovarian endometrioid adenocarcinoma.