MYC and breast cancer: However, as miRNA let-7a downregulates c-Myc, a proto-oncogene [13], expression in other cancers [44] leading to chemoresistance and increased tumor aggression [45], it may perform in the same way during breast cancer, leading to the results found by Ohno et al. Doxorubicin (Dox), when loaded into immature dendritic cell-derived EVs tagged with the iRGD peptide was also successful in targeting breast cancer cells and greatly inhibiting tumor growth without toxicity to normal cells [46].