The results of these two studies were contradictive to findings documented in patients with other malignancies (breast, prostate and lung cancer), and did not confirm the association of SDF-1/CXCR4 signaling pathway with a more aggressive phenotype of tumor, as the expression of proteins involved in this pathway proved lower in tumors characterized by worse prognosis [15]. The gene discussed is CXCR4; the disease is lung cancer.