We further investigated the expression of several members of the CXCLs/CXCRs family in 13 cases of BRAFV600E-expressing PTC tissues by real-time PCR and found that CXCL1, CXCL2 and CXCL12 expression was significantly upregulated in the cancer area compared with the normal tissue (P=0.02, P=0.004 and P=0.03, respectively, Student's t-test), whereas, among the receptors of these chemokines, only CXCR4 was significantly upregulated (P=0.02, Student's t-test; Fig. 5c, left panel). The gene discussed is CXCR4; the disease is cancer.