CXCR4 and small cell lung carcinoma: uPAR and CXCR4 co-expression predicts worse prognosis in small cell lung cancer patients 49, characterizes mesenchymal circulating tumour cells from breast cancer patients with lymph nodes involvement 50, increases in hypoxic cells sorted from cervical and lymph nodal xenograft tumours 51, is down-regulated by antimetastatic COX-2 inhibitors 52.