CXCR4 and lung carcinoma: Tyrosylprotein sulfotransferase 1 and 2 (TPST-1 and TPST-2) are both responsible for the catalysis of tyrosine sulfation of chemokine receptors, such as CXCR4 (Refs 93, 95, 96, 97, 98, 99) (37), it has previously been demonstrated that the TPST 1 expression was significantly associated with lymph node metastasis and the TNM stage in patients with lung cancer and may be a negative prognostic biomarker of lung cancer (38, 39).