The direct involvement of leptin/leptin receptor mediated signaling in the observed upregulation of exosomes release from breast cancer cells was demonstrated by using a selective inhibitor of leptin activity, the peptide LDFI, a small peptide of the wild type sequence of leptin binding site I, that we recently demonstrated to specifically inhibit both in vitro and in vivo leptin signaling pathway [31]. This evidence concerns the gene LEP and breast cancer.