Within the BC group, the mean GPNMB concentration was 8.079 (±11.348) ng/mL in patients with local disease (stages 0, I, II, or III) and 8.394 (±11.308) ng/mL in patients with stage IV or MBC; however, there was no significant difference between patients with local disease and MBC. This evidence concerns the gene GPNMB and breast cancer.