ESR1 and neoplasm: AT3-OVA-ER cells showed less T cell–mediated killing than did AT3-OVA control cells in the different tumor/effector (T/E) ratios (Figure 2C), along with a reduction of T cell activation (CD69) and cytotoxic markers (IFN-γ and granzyme B [GZMB]) (Figure 2D).