LEP and obesity due to melanocortin 4 receptor deficiency: We reported moderate weight gain and increases in adiposity, with obesity-like detection of crown-like structures in adipose, and elevated obesity-associated endocrine factors, including leptin, using a transgenic breast cancer model in the FVB/N strain (C3(1)-T antigen, or C3(1)-Tag) [81, 82, 167–169].