To understand the role of Epstein-Barr virus (EBV) and viral products in associated with immunophenotype and clinical outcome of primary nasopharyngeal carcinoma (NPC), the expression levels of chemokines IFN-g-induced protein 10 (IP-10, CXCL10), stromal-derived factor-1 (SDF-1, CXCL12) and its receptor CXCR4 was investigated in 56 primary NPC biopsy specimens from Chinese NPC patients in parallels with LMP1 antigen and EBER1 by immunohistochemisty (IHC) and in situ hybridization (ISH). Moreover, the expression levels of HLA class I (b-microglobulin) and II antigen (HLA-DR), and co-stimulatory molecule CD54 were also evaluated in 31 out of these 56 patients using immunohistochemisty (IHC). Our results showed that (a) the elevated expression levels of IP10, SDF-1, CXCR4, b-microglobulin, HLA-DR and CD54 in NPC lesions was 66%, 36%, 30%, 42%, 55% and 69%, respectively. The differentiated nonkeratinizing and undifferentiated types of nasopharyngeal carcinoma (NPC) are associated with Epstein-Barr virus (EBV) in South China, which has the highest incidence rate in the world. 1 The EBV latent type II antigens include nuclear antigen 1 (EBNA1), and latent membrane protein 1 (LMP1, in approximately 50%, seen in ref.2) and protein 2 (LMP2), in addition small non-polyadenylated viral RNAs non-coding nuclear RNAs (EBERs) and BamHI-A rightward transcripts (BARTs) expressed in NPC tumor cells. The expressions of EBV antigens in NPC tumor cells provide the targets for adoptive immunotherapy. [3][4][5][6] However, the poorly differentiated NPC is always characterized by the presence of a highly cellular lymphoid stroma admixed with tumor cells. 7 However, the role of local immunity surrounding NPC cells and the role EBV and viral products expressed in tumor cell remain unclear, which is associated with the expression of immune-related molecules including chemokines and receptors, HLA class I and II antigens, and co-stimulatory molecules and the role of EBV and viral products to alter the expression of immune-related molecules on tumor cells. It has been reported that the expression pattern of immune related-molecules on tumor cells will affect the outcome of T-cell-based adoptive immunotherapy for NPC. [8][9][10] In the tumor bed, chemokines and cytokines are secreted by both tumor-infiltrating immune cells and the tumor cells, and these chemokines and cytokines are capable of pleiotropic effects. 8 For example, IP-10 is a CXC chemokine produced by endothelial cells and macrophages post-stimulated by IFNg. IP-10 can induce rapid and transient adhesion of human IL-2-stimulated T lymphocytes to endothelial cells through its receptor CXCR3, which is selectively expressed on activated T cells. It is thought that expression of IP-10 in tumor cells induces potent anti-tumor functions, such as induction of the Th1 immune response and inhibition of angiogenesis. 11-13 SDF-1 is a a-chemokine, and bind to the only receptor CXCR4. Recent studies suggested that the SDF-1/CXCR4 axis play an important and unique role not only in th...