Accordingly, we demonstrated that knock down of LAP3 and DPP7 in D492HER2 cells reduced the positive activity of melflufen indicating that other aminopeptidases could play a role in breast cancer treatment, an important finding which needs further evaluation.When compared to the commonly used breast cancer drug doxorubicin we were able to show that melflufen is more potent both in vitro and in vivo. This evidence concerns the gene DPP7 and breast carcinoma.