The mean GPNMB concentrations in the BC, CC, and GC groups were 8.163 (±11.293) ng/mL, 5.751 (±3.764) ng/mL, and 6.55 (±10.541) ng/mL, respectively; the BC group showed significantly higher levels of serum GPNMB than the CC groups (P = 0.021) (Fig.2B). This evidence concerns the gene GPNMB and breast cancer.