ESR1 and breast cancer: Table 2 shows that ZER and ZER-HPβCD complex exhibit the highest percentage of inhibition (91.4 and 90.4%, respectively) against estrogen receptor positive breast cancer cells (MCF-7) when co-administered with 10× of TP5-iRGD peptide, however, the percentage of inhibition inversely reduced by increasing the ratio of peptide to 20× or 30×.