Results showed that cats with HER2-positive and TN Normal-Like mammary carcinoma displayed higher serum VEGF-A levels than control group (1748.6 ± 3558.4 pg/mL vs. 0.0 pg/mL, p = 0.001; 1881.9 ± 2927.9 pg/mL vs. 0.0 pg/mL, p = 0.020; respectively, Figure 1A). This evidence concerns the gene ERBB2 and breast carcinoma.