Regarding the serum leptin levels, results obtained showed that cats with luminal B or HER2-positive mammary carcinomas had lower serum leptin levels than healthy animals (0.00 vs. 13.89 pg/ml, p < 0.01; 0.83 vs. 13.89 pg/mL, p < 0.05, respectively, Figure 3A), and considering the analysis with no outliers, the same results could be reported (p = 0.0021). The gene discussed is ERBB2; the disease is breast carcinoma.