To further confirm the apoptosis induction, we treated the ER+/HER2− MCF-7 breast cancer cell line with everolimus, INK128, and RMC-6272 for 24 h, and observed that INK128 and RMC-6272 both induced cleaved poly(ADP-ribose) polymerase (PARP), a molecular marker of apoptosis, whereas everolimus did not (Fig. 2D). Here, ERBB2 is linked to breast cancer.