Interestingly, we found that cats with elevated serum SDF-1 levels are associated with mammary carcinomas showing smaller size (≤3 cm; p=0.012), lower ki-67 index (< 14%; p=0.037) and HER2 overexpression (p=0.0001), with 9 from 11 HER2-overexpressing mammary carcinomas (81.8%), being classified as luminal B-like subtype, which is associated with a better outcome than HER2 subtype, both in cat [7] and humans [57–60]. Here, ERBB2 is linked to breast carcinoma.