Significant associations were found between cats with elevated serum SDF-1 levels (≥ 2 ng/ml) smaller mammary carcinomas (≤ 3 cm; p=0.012; OR = 0.068; 95% CI: 0.007-0.63) and tumors with lower Ki-67 index (< 14%, p=0.037; OR = 0.185; 95% CI: 0.04-0.84) (Table 3). This evidence concerns the gene CXCL12 and breast carcinoma.