ESR1 and neoplasm: Inmunohistochemical analysis of the tumor from animals inoculated with MCF-7 Tet-Off empty vector and from from animal inoculated with MCF-7 Tet-Off/ACSL4 and treated with doxycycline showed almost all cells expressing ERα (figure 3 G and H) and PR (figure 3 I and J) respectively.