To determine whether the CXCL1/CXCR2 axis is involved in osteosarcoma lung metastasis, we examined the expression of CXCL1 in human pulmonary artery endothelial cells (HPAECs), which reside in pulmonary vasculature, where metastatic foci are found. The gene discussed is CXCR2; the disease is osteosarcoma.