Nasopharyngeal carcinoma and lymphoinfiltration

Identification and validation of immune-related methylated genes as diagnostic and prognostic biomarkers of nasopharyngeal carcinoma

BACKGROUND

Nasopharyngeal carcinoma (NPC) is a common malignancy occurring in the head and neck. Identification of immune-related methylated biomarkers might be helpful for NPC detection and prognostic evaluation.

METHODS

A co-methylation network based on WGCNA was constructed to identify modules associated with NPC and immune cells. In combination with differentially expressed genes (DEGs) and immune-related genes from ImmPort database, the candidate immune-related methylated genes (IRMGs) were obtained.

RESULTS

Our combined analysis identified 12 IRMGs. Among them, both the methylation and mRNA expression of CCL28, CSK, and PRKCB were correlated with the infiltration of B cells. CD1D, CR2, and GDF10 were favorable markers. Demethylation experiments validated that downregulation of GDF10, PRKCB, SLC40A1, and TGFBR3 in NPC resulted from promoter hypermethylation. Additionally, a diagnostic model was developed and exhibited high discriminative accuracy.

CONCLUSIONS

These results provided a group of immune-related methylated biomarkers that may help with the diagnosis and prognosis of NPC.

Immunosuppressive Tumor Microenvironment and Immunotherapy of Epstein–Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause different types of cancer in human beings when the virus infects different cell types with various latent patterns. EBV shapes a distinct and immunosuppressive tumor microenvironment (TME) to its benefit by influencing and interacting with different components in the TME. Different EBV-associated malignancies adopt similar but slightly specific immunosuppressive mechanisms by encoding different EBV products to escape both innate and adaptive immune responses. Strategies reversing the immunosuppressive TME of EBV-associated malignancies have been under evaluation in clinical practice. As the interactions among EBV, tumor cells, and TME are intricate, in this review, we mainly discuss the epidemiology of EBV, the life cycle of EBV, the cellular and molecular composition of TME, and a landscape of different EBV-associated malignancies and immunotherapy by targeting the TME.

Identification of tumor-infiltrating immune cells and microenvironment-relevant genes in nasopharyngeal carcinoma based on gene expression profiling

AIMS

The purpose of this study was to investigate the prognostic significance of tumor-infiltrating immune cells and microenvironment-relevant genes in nasopharyngeal carcinoma (NPC) and their correlations.

MATERIALS AND METHODS

The "xCell" algorithm was used to calculate the enrichment scores for 33 immune cells in the samples of GSE12452, GSE40290, GSE53819, GSE68799, and GSE102349. The difference of immune cells between NPC group and non-cancerous group and the prognostic value of the immune cells were analyzed. Besides, based on the Microenvironment scores, the differentially expressed genes (DEGs) between the high- and low-score groups were screened to identify the microenvironment-relevant hub genes. Furthermore, the DEGs were used to establish a risk score model for predicting progression-free survival (PFS) via LASSO penalized Cox regression.

KEY FINDINGS

The scores of B-cells and Memory B-cells of NPC were significantly lower than those of non-cancerous tissues, and they were positively associated with PFS. Moreover, 10 hub genes (PTPRC, CD19, CD79B, BTK, CD79A, SELL, MS4A1, CD38, CD52, and CD22) were identified and positively correlated with B-cells, Memory B-cells, and Microenvironment scores in GSE12452, GSE68799, and GSE102349. High expression levels of CD22, CD38, CD79B, MS4A1, SELL, and PTPRC were associated with longer PFS. Besides, a risk score model composed of DARC, IL33, IGHG1, and SLC6A8 was established with a good performance for PFS prediction.

SIGNIFICANCE

These results enhance our understanding of the composition and prognostic significance of tumor-infiltrating immune cells in NPC lesions, and provide potential targets for prognostication and immunotherapy for NPC patients.

The Microenvironment in Epstein-Barr Virus-Associated Malignancies

The Epstein–Barr virus (EBV) can cause a wide variety of cancers upon infection of different cell types and induces a highly variable composition of the tumor microenvironment (TME). This TME consists of both innate and adaptive immune cells and is not merely an aspecific reaction to the tumor cells. In fact, latent EBV-infected tumor cells utilize several specific mechanisms to form and shape the TME to their own benefit. These mechanisms have been studied largely in the context of EBV+ Hodgkin lymphoma, undifferentiated nasopharyngeal carcinoma, and EBV+ gastric cancer. This review describes the composition, immune escape mechanisms, and tumor cell promoting properties of the TME in these three malignancies. Mechanisms of susceptibility which regularly involve genes related to immune system function are also discussed, as only a small proportion of EBV-infected individuals develops an EBV-associated malignancy.

N-acetylcysteine (NAC) ameliorates Epstein-Barr virus latent membrane protein 1 induced chronic inflammation

Chronic inflammation results when the immune system responds to trauma, injury or infection and the response is not resolved. It can lead to tissue damage and dysfunction and in some cases predispose to cancer. Some viruses (including Epstein-Barr virus (EBV)) can induce inflammation, which may persist even after the infection has been controlled or cleared. The damage caused by inflammation, can itself act to perpetuate the inflammatory response. The latent membrane protein 1 (LMP1) of EBV is a pro-inflammatory factor and in the skin of transgenic mice causes a phenotype of hyperplasia with chronic inflammation of increasing severity, which can progress to pre-malignant and malignant lesions. LMP1 signalling leads to persistent deregulated expression of multiple proteins throughout the mouse life span, including TGFα S100A9 and chitinase-like proteins. Additionally, as the inflammation increases, numerous chemokines and cytokines are produced which promulgate the inflammation. Deposition of IgM, IgG, IgA and IgE and complement activation form part of this process and through genetic deletion of CD40, we show that this contributes to the more tissue-destructive aspects of the phenotype. Treatment of the mice with N-acetylcysteine (NAC), an antioxidant which feeds into the body’s natural redox regulatory system through glutathione synthesis, resulted in a significantly reduced leukocyte infiltrate in the inflamed tissue, amelioration of the pathological features and delay in the inflammatory signature measured by in vivo imaging. Reducing the degree of inflammation achieved through NAC treatment, had the knock on effect of reducing leukocyte recruitment to the inflamed site, thereby slowing the progression of the pathology. These data support the idea that NAC could be considered as a treatment to alleviate chronic inflammatory pathologies, including post-viral disease. Additionally, the model described can be used to effectively monitor and accurately measure therapies for chronic inflammation.

Enhancing antitumor efficacy of chimeric antigen receptor T cells through constitutive CD40L expression

Adoptive cell therapy with genetically modified T cells expressing a chimeric antigen receptor (CAR) is a promising therapy for patients with B-cell acute lymphoblastic leukemia. However, CAR-modified T cells (CAR T cells) have mostly failed in patients with solid tumors or low-grade B-cell malignancies including chronic lymphocytic leukemia with bulky lymph node involvement. Herein, we enhance the antitumor efficacy of CAR T cells through the constitutive expression of CD40 ligand (CD40L, CD154). T cells genetically modified to constitutively express CD40L (CD40L-modified T cells) demonstrated increased proliferation and secretion of proinflammatory TH1 cytokines. Further, CD40L-modified T cells augmented the immunogenicity of CD40(+) tumor cells by the upregulated surface expression of costimulatory molecules (CD80 and CD86), adhesion molecules (CD54, CD58, and CD70), human leukocyte antigen (HLA) molecules (Class I and HLA-DR), and the Fas-death receptor (CD95). Additionally, CD40L-modified T cells induced maturation and secretion of the proinflammatory cytokine interleukin-12 by monocyte-derived dendritic cells. Finally, tumor-targeted CD19-specific CAR/CD40L T cells exhibited increased cytotoxicity against CD40(+) tumors and extended the survival of tumor-bearing mice in a xenotransplant model of CD19(+) systemic lymphoma. This preclinical data supports the clinical application of CAR T cells additionally modified to constitutively express CD40L with anticipated enhanced antitumor efficacy.

Method for the validation of immunohistochemical staining using SCID mouse xenografts: expression of CD40 and CD154 in human non-small cell lung cancer

This report proposes a concept for the standardization of immunohistochemical evaluation. Immunohistochemical staining has several problems associated with the sensitivity of the technical process and standardization of the assessment of potent staining. We provided data focusing on this concept through immunostaining for CD154 in non-small cell lung cancer (NSCLC). We used two types of anti-CD154 antibody as primary antibodies in immunohistochemical staining, as previously reported. Western blot analysis confirmed strong CD154 expression in the cultured cell line PC10, but not in LK2. We also assessed CD154 expression in SCID mouse xenografts of these cell lines. SCID xenograft data on western blot analysis were consistent with those of cultured cell lines. These xenografts could thus be used as positive or negative tissue controls for CD154 immunostaining. Primary antibodies should therefore be confirmed as recognizing target lesions, while control tissue specimens should be objectively confirmed as having target products using another experimental method. Our method would allow results to be unified at more than one laboratory and could act as an objective control assessment method in immunohistochemistry.

Lymphocyte deficiency limits Epstein-Barr virus latent membrane protein 1 induced chronic inflammation and carcinogenic pathology in vivo

BACKGROUND

The importance of the malignant cell environment to its growth and survival is becoming increasingly apparent, with dynamic cross talk between the neoplastic cell, the leukocyte infiltrate and the stroma. Most cancers are accompanied by leukocyte infiltration which, contrary to an anticipated immuno-protective role, could be contributing to tumour development and cancer progression. Epstein-Barr virus (EBV) associated cancers, including nasopharyngeal carcinoma and Hodgkin's Disease, show a considerable leukocyte infiltration which surrounds the neoplastic cells, raising the questions as to what role these cells play in either restricting or supporting the tumour and what draws the cells into the tumour. In order to begin to address this we have studied a transgenic model of multistage carcinogenesis with epithelial expression of the EBV primary oncoprotein, latent membrane protein 1 (LMP1). LMP1 is expressed particularly in the skin, which develops a hyperplastic pathology soon after birth.

RESULTS

The pathology advances with time leading to erosive dermatitis which is inflamed with a mixed infiltrate involving activated CD8+ T-cells, CD4+ T-cells including CD4+/CD25+/FoxP3+ Treg cells, mast cells and neutrophils. Also significant dermal deposition of immunoglobulin-G (IgG) is observed as the pathology advances. Along with NF-kappaB activation, STAT3, a central factor in inflammation regulation, is activated in the transgenic tissue. Several inflammatory factors are subsequently upregulated, notably CD30 and its ligand CD153, also leukocyte trafficking factors including CXCL10, CXCL13, L-selectin and TGFβ1, and inflammatory cytokines including IL-1β, IL-3 and the murine IL-8 analogues CXCL1, CXCL2 and CXCL5-6, amongst others. The crucial role of mature T- and/or B-lymphocytes in the advancing pathology is demonstrated by their elimination, which precludes mast cell infiltration and limits the pathology to an early, benign stage.

CONCLUSIONS

LMP1 can lead to the activation of several key factors mediating proliferation, angiogenesis and inflammation in vivo. With the initiation of an inflammatory programme, leukocyte recruitment follows which then itself contributes to the progressing pathology in these transgenic mice, with a pivotal role for B-and/or T-cells in the process. The model suggests a basis for the leukocyte infiltrate observed in EBV-associated cancer and its supporting role, as well as potential points for therapeutic intervention.

Primary and malignant cholangiocytes undergo CD40 mediated Fas dependent apoptosis, but are insensitive to direct activation with exogenous Fas ligand

INTRODUCTION

Cholangiocarcinoma is a rare malignancy of the biliary tract, the incidence of which is rising, but the pathogenesis of which remains uncertain. No common genetic defects have been described but it is accepted that chronic inflammation is an important contributing factor. We have shown that primary human cholangiocyte and hepatocyte survival is tightly regulated via co-operative interactions between two tumour necrosis family (TNF) receptor family members; CD40 and Fas (CD95). Functional deficiency of CD154, the ligand for CD40, leads to a failure of clearance of biliary tract infections and a predisposition to cholangiocarcinoma implying a direct link between TNF receptor-mediated apoptosis and the development of cholangiocarcinoma.

AIMS

To determine whether malignant cholangiocytes display defects in CD40 mediated apoptosis. By comparing CD40 and Fas-mediated apoptosis and intracellular signalling in primary human cholangiocytes and three cholangiocyte cell lines.

RESULTS

Primary cholangiocytes and cholangiocyte cell lines were relatively insensitive to direct Fas-mediated killing with exogenous FasL when compared with Jurkat cells, which readily underwent Fas-mediated apoptosis, but were extremely sensitive to CD154 stimulation. The sensitivity of cells to CD40 activation was similar in magnitude in both primary and malignant cells and was STAT-3 and AP-1 dependent in both.

CONCLUSIONS

1) Both primary and malignant cholangiocytes are relatively resistant to Fas-mediated killing but show exquisite sensitivity to CD154, suggesting that the CD40 pathway is intact and fully functional in both primary and malignant cholangiocytes 2) The relative insensitivity of cholangiocytes to Fas activation demonstrates the importance of CD40 augmentation of Fas dependent death in these cells. Agonistic therapies which target CD40 and associated intracellular signalling pathways may be effective in promoting apoptosis of malignant cholangiocytes.

Cytokeratin 8 silencing in human nasopharyngeal carcinoma cells leads to cisplatin sensitization

By comparing protein profiles of nasopharyngeal carcinoma HONE1 cells to transformed nasopharyngeal epithelial NP 69 cells, several clusters of differentially expressed proteins were identified. The increased expression of cytokeratin 8 (CK8) and pyruvate kinase M2 was a common feature in four NPC cell lines compared to the two transformed epithelial cell lines. Suppression of CK8 was associated with the sensitivity to cisplatin in HONE1 cells; while overexpression of CK8 provided resistance to cisplatin-mediated apoptosis; and this protection occurred through an enhanced phosphorylation of c-Jun NH(2)-terminal kinase (JNK). Our findings implicate an underlying molecular mechanism in which CK8 is required for cisplatin resistance.

A11 Tetramer-assisted characterization of Rta-specific CD8+ T-cell responses in healthy virus carriers

HLA Class I-restricted CD8(+) T-cell responses are believed to play an important role in controlling Epstein-Barr virus (EBV) infection, which has been consistently associated with nasopharyngeal carcinoma (NPC). Immediate early transactivator Rta of EBV has been shown to be associated with the reactivation of EBV from latency and drive the lytic cascade of EBV and comprise an important target for EBV-specific cellular cytotoxicity. Furthermore, BRLF1 is specifically expressed in NPC tumor cells. The protein product of BRLF1, Rta, could then be considered as a NPC tumor antigen. Therefore, cellular immunity against Rta represents a very important part of the immunity against NPC, as they should prevent the replication of EBV. In the present study, Rta-specific CD8(+) T-cell responses in healthy virus carriers were characterized by using A1101 tetramer containing the known Rta epitope ATIGTAMYK (134-142). We clearly showed A1101/ATIGTAMYK tetramer-reactive CD8(+) T cells in the circulation of healthy virus carriers, ranging from 2.13 to 9.03%. We then studied the expression of perforin and interferon-gamma (IFN-gamma) secretion in these Rta-specific T cells. Our study demonstrated that Rta-specific T cells are capable of IFN-gamma production and nearly 90% of the Rta-specific CD8(+) T cells expressed perforin. Presumably, these are the cells that play an important role in determining the initiation of the lytic cycle or the clearance of EBV.

Expression of cytokine and chemokine genes in Epstein-Barr virus-associated nasopharyngeal carcinoma: comparison with Hodgkin's disease

Nasopharyngeal carcinoma (NPC) and Hodgkin's disease (HD) are characterized by their association with Epstein-Barr virus (EBV) and the presence of an intense lymphoid stroma, consisting of T lymphocytes and other reactive cells. In both entities, the tumour cells express viral proteins known to provide target epitopes for cytotoxic T-cells (CTLs), yet in vivo, the tumour cells appear to escape CTL recognition. A comparative in situ hybridization study of cytokine and chemokine gene expression in NPC and HD has been undertaken, focusing on cytokines which are known to be inducible by EBV in vitro. Hodgkin and Reed-Sternberg (HRS) cells expressed interleukin (IL)-6, IL-8, and IL-10, and the thymus and activation regulated chemokine (TARC) in 15/22, 0/22, 5/22, and 16/21 cases, respectively. In NPC, the epithelial tumour cells showed expression of IL-6 in 3/43 cases and of IL-8 in 2/40 cases. There was no detectable expression of IL-10 and TARC in these cases. These data confirm that HRS cells frequently express cytokine and chemokine genes and suggest that this may enable HRS cells to modulate the immune response in their microenvironment and to escape CTL detection. In contrast, NPC tumour cells show only rare expression of IL-6 and IL-8 and no detectable expression of IL-10 and TARC. Thus, the results suggest that the mechanisms employed by the EBV-positive tumour cells to escape immune recognition and destruction differ between HD and NPC.

CD40 expressed on human melanoma cells mediates T cell co-stimulation and tumor cell growth

CD40 is a 50 kDa molecule, a member of the tumor necrosis factor/nerve growth factor receptor family. It is expressed on B cells, monocytes, dendritic cells and various malignant cells. While the critical relevance of this molecule in T cell-dependent B cell activation is already established, the biological role of CD40-CD154 interaction in non-hematopoietic cells is still unknown. Here we show that CD40 is functionally expressed on human melanoma-derived cell lines. No correlation between surface CD40 expression and the origin of the cell line, primary versus metastatic, was observed. Melanoma cells were shown to be able to co-stimulate TCR-triggered human T cells; moreover, because they do not express CD80 or CD86 co-stimulatory structures, the involvement of additional pathways have to be postulated. We have identified CD40 as one of the molecules involved in melanoma cell-mediated co-stimulation of anti-CD3-triggered human CD4(+) T lymphocytes. In addition, a CD40-dependent pathway, able to enhance tumor cell proliferation at low serum concentrations, in vitro, has been shown to be functional in human melanoma cell lines.

Cytokine regulation of CD40 expression in fetal human astrocyte cultures

CD40 can participate in inflammatory processes after binding its cognate ligand (CD40L). We found that fetal human astrocytes constitutively express CD40 mRNA and protein. Upon incubating cultures with proinflammatory cytokines (TNF-alpha, IL-1beta and IFN-gamma) or with lipopolysaccharide (LPS), CD40 expression was increased. No change in CD40 expression was noted in astrocyte cultures incubated with IL-6, HIV or gp41. Astrocytes also showed increased release of proinflammatory cytokines TNF-alpha, IL-1beta and IL-6 after incubation with CD40L peptide. These observations suggest a role for CD40 in central nervous system (CNS) inflammation and that CD40/CD40L autocrine or paracrine pathways may mediate this role.

Expression of Epstein-Barr virus latent membrane proteins leads to changes in keratinocyte cell adhesion

Epstein-Barr virus (EBV) has 3 latent membrane proteins (LMPs)--LMP1, LMP2a, and LMP2b--which are expressed in nasopharyngeal carcinoma. Using keratinocyte cell lines expressing LMP2a and LMP2b and coexpressing LMP1/LMP2a, we grew organotypic raft cultures to analyze changes in morphology and expression of the cell adhesion molecule ICAM-1; alpha2, alpha3, alpha5, beta1, and alpha6beta4 integrins; laminin 5; E-cadherin; and desmoplakin. Cells expressing LMP2a or LMP2b were defective in their ability to mature and progress through normal squamous stratification when compared to the parental cell lines. Cells coexpressing LMP1/LMP2a additionally demonstrated "pseudoinvasion" into the raft dermal equivalent. There was a consistent and dramatic up-regulation in the suprabasal expression of laminin 5 and alpha6beta4 and beta1 integrins in the LMP-expressing cell lines. ICAM-1, not expressed in the control cell lines, was up-regulated in the LMP-expressing cell lines. Expression of alpha3 and alpha5 integrins was also up-regulated in the LMP-expressing cell lines, while alpha2 demonstrated a loss of the normal basal layer expression. E-cadherin and desmoplakin expression patterns were essentially unchanged. We conclude that LMP2a and LMP2b singly, and LMP1/LMP2a coexpressed, are capable of altering keratinocyte cell adhesion molecule expression consistent with nasopharyngeal carcinoma.

Increased production of interferon-gamma by tumour infiltrating T lymphocytes in nasopharyngeal carcinoma: indicative of an activated status

Undifferentiated nasopharyngeal carcinomas (UNPC) are characterised by an association with Epstein-Barr virus and an abundant lymphoid stroma. We studied the functional status of the infiltrating T cells in ten UNPC biopsies using an immunohistochemical approach. Twelve non-NPC biopsies were included as controls. Tumour cells of UNPC were positive for HLA class I (10/10) and II (8/10), LMP1 (3/10), and CD86 (6/10). Tumour infiltrating T cells (TILs) were detected with antibodies directed at CD3, CD4, and CD8, and shown to be comparable to that in the control biopsies. Although expression of CD28 was shown to be decreased in TILs, expression of CD25 and IFN-gamma at a relatively high percentage could be consistently detected in the UNPC biopsies. These data suggest that TILs in UNPC are in an activated status, and this T cell response is possibly directed at the tumour cells.

B- and T-Lymphocyte distribution in benign and malignant lymphoepithelial lesions of the parotid gland: Correlation with Epstein-Barr virus expression and a proposed mechanism of malignant transformation

Epstein-Barr virus expression in malignant lymphoepithelial lesions (LEL) of the parotid gland has been well established. The virus is occasionally expressed in benign LEL, especially in immunocompromised hosts. The pathogenesis of the disease as it relates to virus expression and lymphocyte subsets has not been clearly defined. In this study, we attempted to identify B- and T-lymphocyte distribution in the lesions as it relates to EBV expression in LELs of the parotid gland. Formalin-fixed paraffin-embedded sections of 18 cases of LEL of the parotid gland were immunohistochemically tested for the distribution of B- and T-lymphocytes in the lesions, using the antibodies L-26 (CD 20) for B-lymphocytes and UCHL-1 (CD-45RO) for T-lymphocytes. The sections were also tested by in situ hybridization for EBV mRNA expression, using the EBER-1 probe specific for EBV-1 gene. The 18 lesions included seven malignant LEL, seven benign LEL and four benign lymphoepithelial cysts. All malignant LELs showed a high and diffuse level of epithelial expression of EBV mRNA. Of the 11 benign lesions, only one case showed focal epithelial expression of EBV mRNA. This was a case of benign LEL in an HIV-positive male. All the benign lesions, except that expressing EBV mRNA, showed a T-/B-lymphocyte ratio averaging 2:1. All cases expressing EBV mRNA, including the case of benign LEL in the HIV-positive patient, showed a T-/B-lymphocyte ratio averaging 1:3. Our findings suggest that a T-lymphocyte-mediated immune response may play an essential role in suppressing proliferation of EBV in benign LEL of the parotid gland. This immune mechanism may be significantly disturbed in the malignant lesions, leading to uncontrolled viral replication and carcinogenesis.

Human epidermal keratinocytes are induced to secrete interleukin-6 and co-stimulate T lymphocyte proliferation by a CD40-dependent mechanism

Although the expression and function of CD40 on B lymphocytes has been well studied, the significance of CD40 on non-lymphoid cells such as keratinocytes (KC) is not as well characterized. We demonstrate in this report that CD40 is expressed by virtually all human KC, and that it functions as an important signaling molecule. Flow cytometry of undifferentiated and terminally differentiated KC indicated that both cell types expressed CD40, as determined by binding to monoclonal antibodies and a recombinant CD40 ligand fusion protein; interferon-gamma (IFN-gamma) treatment of KC increased CD40 expression. Cultured KC also expressed 1.5-kb CD40 transcripts. Activation of KC cell surface CD40 using the monoclonal antibody G28.5 resulted in the rapid generation of a 50-kDa tyrosine phosphorylated polypeptide, as well as a dose-dependent increase in the secretion of interleukin-6, a cytokine that has been linked to KC proliferation. KC also co-stimulated a significant T lymphocyte proliferative response to the mitogen phytohemagglutinin that was CD40 dependent. These data indicate that KC constitutively express a low level of functional CD40 and regulate their expression in response to IFN-gamma. These data support the concept that KC, via their expression of CD40, have the capacity to amplify inflammation in the skin by interacting with CD40 ligand-bearing T cells.

Infiltrating lymphocytes and accessory cells in nasopharyngeal carcinoma

The infiltrating lymphocytes (LCs) and accessory cells (ACs) including dendritic cells (DCs) and monocytes/macrophages in nasopharyngeal biopsies taken from 4 groups of nasopharyngeal carcinoma (NPC) patients were observed by using an immunostaining technique and the correlation of the results to the clinical manifestations and follow-up data was examined. The findings were as follows. (1) NPCs without lymph node metastasis always had marked infiltrating LCs and DCs as compared with those with lymph node(s) metastasis. (2) Advanced NPCs with lymph node(s) involvement (T1-4N1-3M0) and a rapid development of distant metastasis followed by death within 1 year after radiotherapy always showed fewer infiltrating LCs and DCs as compared with those with lymph node(s) metastasis (T1-4N1-3M0) and having longer than 5-year survival after radiotherapy. The amount of both LCs and ACs, especially DCs, infiltrating in NPC tissues appears to be an indicator of the activity of host immune defence mechanisms against cancer and influences the progression of the neoplasm as well as the prognosis.

Epstein-Barr virus carriage by nasopharyngeal carcinoma in situ

We studied the distribution of the EBV genome in tumour biopsies obtained from 42 patients with poorly differentiated or undifferentiated nasopharyngeal carcinoma (NPC) and 3 patients with well-differentiated NPC. Six carcinoma in situ (CIS) foci were seen in 5 tumour specimens. By in-situ hybridization, multiple copies of the EBV genome were detected in some of the tumour cells in 3 CIS lesions involving the full thickness of the mucosal epithelium, but without microinvasion, while the viral genome was present in the majority of the tumour cells contained in another 3 CIS lesions with microinvasion. In agreement with previous findings, poorly differentiated and undifferentiated carcinomas regularly carried the viral genome, the number of copies of which was similar to that seen in CIS, while some, but not all, of the tumour cells of the well-differentiated histological type carried the virus. The viral genome was otherwise rarely detected in other areas of the mucosal epithelium and, where present, the viral carriage was confined to a few epithelial cells, in which the viral genome contents were markedly lower than in tumour cells. These results suggest that EBV may first become associated with NPC at an early stage of the disease shortly after the tumour has been initiated.