Indeed, cats with elevated serum SDF-1 levels have 53 times more likelihood to show HER2-positive tumor status and increased serum HER2 values (p<0.0001), corroborating the recent data that associates the HER2 tumor status with the serum HER2 levels [11], as also reported in humans [55, 56]. This evidence concerns the gene CXCL12 and neoplasm.