EPCAM and breast cancer: This expression variance aligns with previous reports on protein levels18, 19 as well as on mRNA expression levels, where it was noted that primary and metastatic breast cancers have 100- to 1000-fold increase compared to normal breast tissue.12 These previous findings also correlate well with the cytotoxic profile of our AuNR/Ag/Dox-EpCAM particles: high EpCAM-expressing TNBC cells were 100-fold more sensitive than low EpCAM-expressing breast cancer cells, rendering a favorable therapeutic index.