Interestingly, a comparison between anti-EpCAM antibodies versus anti-EpCAM aptamers revealed that aptamers display better tumor penetration and retention in HT29 tumors in mice [122] Indeed, in a 2016 study, an anti-EpCAM aptamer was used to deliver small interfering RNA (siRNA), which reduced EpCAM mRNA expression and protein levels, as well as reducing viability in breast MCF-7 and retinoblastoma WERI-Rb1 cells [123]. This evidence concerns the gene EPCAM and retinoblastoma.