In addition, a positive correlation was found between serum SDF-1 levels and serum HER2 levels (r=0.69, 95% CI: 0.46 - 0.84, p<0.0001, Figure 6), corroborating the previous results, since the serum HER2 levels are associated with tumor HER2 status [11]. Here, ERBB2 is linked to neoplasm.