Overall, the optical density of CXCL12 mRNA and protein in 50 cases of tissues is 0.85 ± 0.11, and 1.22 ± 0.16, respectively, compared with those in paired non-tumor tissues (0.29 ± 0.06, and 0.35 ± 0.06, respectively). The gene discussed is CXCL12; the disease is neoplasm.