LEP and breast cancer: Interestingly, recent in vivo studies from our group using the same mammary tumor model but a different HFD (60% instead of 33%, as we used here), and a more aggressive treatment scheme with the peptide inhibitor (two injections per week instead of one), showed significant results in tumor regression, suggesting a more relevant role for leptin in the same tumor model in mice fed a different diet and treated more aggressively with the leptin inhibitor [54].