Nasopharyngitis Tissues Research Articles

EBV-miR-BART1 is involved in regulating metabolism-associated genes in nasopharyngeal carcinoma

EBV-miR-BART1 has been found to be highly expressed in some cancers including nasopharyngeal carcinoma (NPC), but its exact roles in the pathogenesis of NPC remain unclear. Here, we did RNA deep sequencing to compare the gene expression profile between EBV-miR-BART1-expressing CNE1 cells and the control cells to determine the possible effects of EBV-miR-BART1 in NPC. Gene expression profiling analysis unexpectedly showed a significant number of up- and down-modulated metabolism-associated genes, such as G6PD, SAT1, ASS1, PAST1, FUT1, SGPL1, DHRS3, B4GALT1, PHGDH, IDH2, PISD, UGT8, LDHB and GALNT1, in EBV-miR-BART1-expressing NPC cells, which were next confirmed by RT-qPCR. Moreover, of these metabolism-genes, PSAT1 and PHGDH expression levels were significantly upregulated and most of other genes were obviously up-expressed in NPC specimens compared with chronic nasopharyngitis (CNP) tissues. Collectively, we for the first time found the effects of EBV-miR-BART1 on the expression of mechanism-associated genes in NPC, suggesting a novel role of EBV-miR-BART1 in cancer metabolism, which remains to be fully elucidated.

Increased phosphorylation of histone H3 at serine 10 is involved in Epstein-Barr virus latent membrane protein-1-induced carcinogenesis of nasopharyngeal carcinoma

BackgroundIncreased histone H3 phosphorylation is an essential regulatory mechanism for neoplastic cell transformation. We aimed to explore the role of histone H3 phosphorylation at serine10 (p-H3Ser10) in Epstein-Barr virus (EBV) latent membrane protein-1 (LMP1)-induced carcinogenesis of nasopharyngeal carcinoma (NPC).MethodsThe expression of p-H3Ser10 was detected by the immunohistochemical analysis in NPC, chronic nasopharyngitis and normal nasopharynx tissues, and its correlation with LMP1 was analyzed in NPC tissues and cell lines. Using the small interfering RNA (siRNA)-H3 and histone H3 mutant (S10A), the effect of histone H3 Ser10 motif on LMP1-induced CNE1 cell proliferation, transformation and activator protein-1 (AP-1) activation were evaluated by CCK-8, focus-forming and reporter gene assay respectively. Mitogen- and stress-activated kinase 1 (MSK1) kinase activity and phosphorylation were detected by in vitro kinase assay and western blot. Using MSK1 inhibitor H89 or siRNA-MSK1, the regulatory role of MSK1 on histone H3 phosphorylation and AP-1 activation were analyzed.ResultsImmunohistochemical analysis revealed that the expression of p-H3Ser10 was significantly higher in the poorly differentiated NPC tissues than that in chronic nasopharyngitis (p <0.05) and normal nasopharynx tissues (p <0.001). Moreover, high level of p-H3Ser10 was positively correlated with the expression of LMP1 in NPC tissues (χ2=6.700, p =0.01; C=0.350) and cell lines. The knockdown and mutant (S10A) of histone H3 suppressed LMP1-induced CNE1 cell proliferation, foci formation and AP-1 activation. In addition, LMP1 could increase MSK1 kinase activity and phosphorylation. MSK1 inhibitor H89 or knockdown of MSK1 by siRNA blocked LMP1-induced phosphorylation of histone H3 at Ser10 and AP-1 activation.ConclusionEBV-LMP1 can induce phosphorylation of histone H3 at Ser10 via MSK1. Increased phosphorylation of histone H3 at Ser10 is likely a crucial regulatory mechanism involved in LMP1-induced carcinogenesis of NPC.

Reduced expression of Dicer11 is associated with poor prognosis in patients with nasopharyngeal carcinoma

Dicer11 plays an important role in generation of microRNA and is dysregulated in a variety of human cancers. The purpose of this study was to evaluate Dicer11 expression and its prognostic value in nasopharyngeal carcinoma (NPC). The protein expression of Dicer1 was examined by immunohistochemistry in 276 NPC specimens, and the mRNA levels of Dicer1 were analyzed by qRT-PCR in 56 NPC and 11 nasopharyngitis tissues. Cox regression analysis was used to identify independent prognostic factors, and a prognostic score model was constructed for survival prediction. Expression of Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and there was a notable positive correlation between the expression levels of Dicer1 mRNA and protein. Low Dicer1 expression was positively correlated with distant metastasis (P < 0.01) and death (P = 0.01). In addition, low expression of Dicer1 was significantly associated with poorer overall survival (HR, 2.32; 95 % CI 1.30-4.14; P < 0.01) and poorer distant metastasis-free survival (HR, 2.56; 95 % CI 1.39-4.74; P < 0.01). Furthermore, multivariate analysis showed that low expression of Dicer1 and tumor-node-metastasis (TNM) stage was independent prognostic indicators for NPC patients. A prognostic score model combining the Dicer1 expression and TNM stage had a better prognostic value than the TNM stage alone model or Dicer1 expression alone model (P < 0.05). Dicer1 was downregulated in NPC tissues at both the mRNA and the protein levels, and low expression of Dicer1 could be served as novel prognostic biomarker for NPC patients.

Aberrant Expression Levels of MTA1 and RECK in Nasopharyngeal Carcinoma: Association with Metastasis, Recurrence, and Prognosis

We investigated the expression and clinical value of MTA1 and RECK genes in patients with nasopharyngeal carcinoma (NPC). We examined MTA1 and RECK expression in nasopharyngeal tissue from patients with chronic nasopharyngitis, lymph nodes with metastasis of NPC, and primary NPC tumor tissue by means of in situ hybridization and analyzed their correlation with the clinicopathologic features of NPC. The positive expression of MTA1 in the NPC tissues and metastatic lymph nodes was significantly higher than that in the chronic nasopharyngitis tissues (p < 0.05). The positive expression of RECK in the NPC tissues and metastatic lymph nodes was significantly lower than that in the chronic nasopharyngitis tissues (p < 0.05). The RECK expression level was inversely correlated with the MTA1 expression level in the NPC tissues (p < 0.05). The increased MTA1 and decreased RECK expressions in the NPC tissues had no association with gender, age, T-stage, or clinical stage (p > 0.05). However, they had a positive correlation with cervical lymph node metastasis, tumor recurrence, and 5-year overall survival rate of the patients with NPC (p < 0.05). Moreover, multivariate analysis showed that MTA1 and RECK expressions were independent prognostic factors for survival (p < 0.05). The conversely abnormal expression levels of MTA1 and RECK may be collectively involved in progression of malignancies and may serve as molecular predictors for metastasis, recurrence, and prognosis of NPC.

Prognostic value of a microRNA signature in nasopharyngeal carcinoma: a microRNA expression analysis

MicroRNAs (miRNAs) can be used as prognostic biomarkers in many types of cancer. We aimed to identify miRNAs that were prognostic in patients with nasopharyngeal carcinoma. We retrospectively analysed miRNA expression profiles in 312 paraffin-embedded specimens of nasopharyngeal carcinoma from Sun Yat-sen University Cancer Center (Guangzhou, China) and 18 specimens of non-cancer nasopharyngitis. Using an 873 probe microarray, we assessed associations between miRNA signatures and clinical outcome in a randomly selected 156 samples (training set) and validated findings in the remaining 156 samples (internal validation set). We confirmed the miRNAs signature using quantitative RT-PCR analysis in 156 samples from a second randomisation of the 312 samples, and validated the miRNA signature in 153 samples from the West China Hospital of Sichuan University in Chengdu, China (independent set). We used the Kaplan-Meier method and log-rank tests to estimate correlations of the miRNA signature with disease-free survival (DFS), distant metastasis-free survival (DMFS), and overall survival. 41 miRNAs were differentially expressed between nasopharyngeal carcinoma and non-cancer nasopharyngitis tissues. A signature of five miRNAs, each significantly associated with DFS, was identified in the training set. We calculated a risk score from the signature and classified patients as high risk or low risk. Compared with patients with low-risk scores, patients with high risk scores in the training set had shorter DFS (hazard ratio [HR] 2·73, 95% CI 1·46-5·11; p=0·0019), DMFS (3·48, 1·57-7·75; p=0·0020), and overall survival (2·48, 1·24-4·96; p=0·010). We noted equivalent findings in the internal validation set for DFS (2·47, 1·32-4·61; p=0·0052), DMFS (2·28, 1·09-4·80; p=0·030), and overall survival (2·87, 1·38-5·96; p=0·0051) and in the independent set for DFS (3·16, 1·65-6·04; p=0·0011), DMFS (2·39, 1·05-5·42; p=0·037), and overall survival (3·07, 1·34-7·01; p=0·0082). The five-miRNA signature was an independent prognostic factor. A combination of this signature and TNM stage had better prognostic value than did TNM stage alone in the training set (area under receiver operating characteristics 0·68 [95% CI 0·60-0·76] vs 0·60 [0·52-0·67]; p=0·013), the internal validation set (0·70 [0·61-0·78] vs 0·61 [0·54-0·68]; p=0·012), and the independent set (0·70 [0·62-0·78] vs 0·63 [0·56-0·69]; p=0·032). Identification of patients with the five-miRNA signature might add prognostic value to the TNM staging system and inform treatment decisions for patients at high risk of progression. Science Foundation of Chinese Ministry of Health, National Natural Science Foundation of China, Pearl River Scholar Funded Scheme, Guangdong Key Scientific and Technological Innovation Program, Guangdong Natural Science Foundation, Fundamental Research Funds for the Central Universities.

Tissue Array Based Immunohistochemical Analysis of TGF-β1,TGF-βRI,TGF-βRII and Smad4 in Nasopharyngeal Carcinoma

Objective Using tissue array-based to assess the expression levels of TGF-β1,TGF-βRⅠ,TGF-βRⅡ and Smad4 and analyze the relationship between these protein and clinicopathologic significance in nasopharyngeal carcinoma(NPC).Methods The expression of TGF-β1,TGF-βRⅠ,TGF-βRⅡ and Smad4 in 163 cases of NPC and 42 cases chronic nasopharyngitis tissues was determined by tissue array and immunohistochemical SP method.Results(1) The positive expression rate of TGF-β1,TGF-βRⅡ and Smad4 in 163 NPC is 52.8%,49.1% and 63.8% respectively,and 19.0%,71.4% and 83.3% in 42 chronic nasopharyngitis tissues(P 0.05).(2) Expression of TGF-β1 and Smad4 are correlated with tumor's clinical stage and biological behavior(P 0.01),but TGF-βRⅠ and TGF-βRⅡ are not(P0.05).(3)The differences in the positive rates of TGF-β1(44.3%,42.9%,73.9% and 78.3%) and Smad4(39.3%,66.1%,56.5% and 73.9%) among stage Ⅰ,Ⅱ,Ⅲ and Ⅳ NPC were significant(P0.05).However,there was no significant difference in the expression of TGF-βRⅠ and TGF-βRⅡ.The local relapse rate was significantly higher in lower 5-year than that in over or equal 5-year in TGF-β1 and Smad4 positive patients(62.7% vs.45.8%.P0.05;75.0% vs.55.8%,P0.05).All the 4 proteins had no correlation to the distant metastasis,ages,gender of NPC(P0.05).Conclusion The expression of TGF-β1,TGF-βRⅠ,TGF-βRⅡ and Smad4 may play an important role in the development of nasopharyngeal carcinoma.

Underlying mechanisms for LTF inactivation and its functional analysis in nasopharyngeal carcinoma cell lines

The lactoferrin (LTF) gene, located at 3p21.3, behaves like a tumor suppressor gene in diverse tumors. To elucidate the exact role of LTF in NPC, we first detected its expression level in seven NPC cell lines by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR). The results showed the mRNA level of LTF was nearly undetectable in all the seven NPC cell lines, while it could be detected in chronic nasopharyngitis tissues. Subsequently, we used methylation-specific PCR (MSP), microsatellite assay, PCR-single-strand conformation polymorphism (PCR-SSCP) and sequencing methods to examine the promoter methylation, loss of heterozygosity (LOH) and gene mutation of LTF in NPC cell lines respectively. Consequently, we found that 100% (7 of 7) of NPC cell lines were methylated in LTF promoter, only one cell line (14%, 1 of 7) had LOH and gene mutation of LTF, respectively, while LTF exhibited re-expression in all cell lines after 5-aza-dC treatment, indicating promoter methylation should be the key mechanism causing LTF downregulation in NPC cell lines. Furthermore, patched methylation assay confirmed that promoter methylation could down-regulate LTF gene expression in NPC cells. Finally, we investigated the function of LTF in NPC cell lines by gene transfection. Restoration of LTF expression in NPC cells resulted in blockage of cell cycle progression, significant inhibition of cell growth and a reduced colony-formation capacity in vitro and obviously weaker tumor formation potential in vivo. In conclusion, our data indicate LTF may participate in NPC carcinogenesis as a negative effector, that is, a tumor suppressor gene.

Expression, genetic and epigenetic alterations of LTF gene in nasopharyngeal carcinoma cell lines

To investigate the expression of LTF mRNA in several nasopharyngeal cancer (NPC) cell lines, and analyze the relationship between the genetic and epigenetic changes and expression of LTF gene. The expression level of LTF was detected in NPC cell lines HNE1, HNE2, HNE3, CNE1, CNE2, 5-8F, 6-10B cells and tissues of 15 cases of chronic nasopharyngitis by RT-PCR. The LTF protein level was analyzed by Western blotting in 6-10B cells. Then LOH, mutation and methylation status of LTF was examined by microsatellites analysis, PCR-SSCP, MSP and bisulfite genomic sequencing, respectively. 15 chronic nasopharyngitis tissues showed stable LTF expression, while there were weak expression in 6-10B cells and absent expression in remaining detected NPC cell lines. There was a significantly lower LTF expression in chronic nasopharyngitis tissues (Z = -3.738, P = 0.000). No LTF protein expression was observed in 6-10B cells. LOH analysis demonstrated that allele loss of LTF wasn't found in NPC cell lines. LTF mutation was noted in 14.3% (1/7) of NPC cell lines. DNA sequencing confirmed the mutation point in the promoter region (-305 bp to -50 bp) was at -218 bp (del T) of LTF gene in the HNE1 cell line. Methylation of LTF gene was not found in chronic nasopharyngitis. However, methylation of LTF promoter was detected in all NPC cell lines. LTF mRNA expression was increased in 5-8F and 6-10B cell lines after treatment with 5-aza-2-deoxycytidine. There is an inactivation of expression of LTF gene in the NPC cell lines. Its molecular mechanism may be related with methylation of promoter region and deletion mutation.

Expression of Ezrin and E-cadherin in nasopharyngeal carcinoma and its significance

To explore the association of Ezrin and E-cadherin expression with the invasion, metastasis and prognois of nasopharyngeal carcinoma. Imunohistochemical SP staining was used to detect the expression of Ezrin and E-cadherin in 42 nasopharyngeal carcinoma and 10 chronic nasopharyngitis specimens. Ezrin protein expression in the nasopharyngeal carcinoma tissues was significantly higher than that in the chronic nasopharyngitis tissues (P<0.05). E-cadherin expression in the nasopharyngeal carcinoma tissues was significantly lower than that in the chronic nasopharyngitis tissues (P<0.05). Expressions of both Ezrin and E-cadherin of nasopharyngeal carcinoma were closely associated with T staging,the cervical lymph node metastases and clinical staging (P<0.05). A negative correlation was found between Ezrin and E-cadherin expression in the nasopharyngeal carcinoma tissues (r=-0.450, P<0.05). Survival analysis showed that the abnormal expression of Ezrin and E-cadhrin, clinical staging and the cervical lymph node metastases were associated with the survival rate of patients with nasopharyngeal carcinoma. A negative correlation is found between Ezrin and E-cadherin expression in the nasopharyngeal carcinoma tissues. Ezrin and E-cadherin are closely related to clinical staging and the cervical lymph node metastases of nasopharyngeal carcinoma,suggesting that they may be important tumor markers for nasopharyngeal carcinoma. Combined detection of the expressions of Ezrin and E-cadherin is helpful for clinical doctors to determine the prognosis of patients with nasopharyngeal carcinoma.

Inactivation of &amp;lt;italic&amp;gt;LARS2&amp;lt;/italic&amp;gt;, located at the commonly deleted region 3p21.3, by both epigenetic and genetic mechanisms in nasopharyngeal carcinoma

Allelic loss of chromosome 3p, including the 3p21.3 region, is found in 95-100% of primary nasopharyngeal carcinoma (NPC) biopsies, suggesting that this region should harbor some tumor suppressor genes (TSGs) closely related to NPC development. Several TSGs located at 3p21.3, such as RASSF1A, LTF and BLU, have been demonstrated to be involved in NPC development. LARS2 (leucyl-tRNA synthetase 2, mitochondrial) is another gene located in the chromosome 3 common eliminated region-1 (C3CER1) at 3p21.3. In this study, we focussed on the epigenetic and genetic alterations of LARS2 in NPC. The mRNA expression of LARS2 was detected in 36 NPC and 8 chronic nasopharyngitis (NP) tissues by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and real-time RT-PCR. Subsequently, the mutation, allelic loss, and methylation status of LARS2 were analysed by polymerase chain reaction-single-strand conformation polymorphism (PCR-SSCP), homozygous deletion (HD) analysis and methylation-specific polymerase chain reaction in primary NPC tissues. No expression or downregulation of LARS2 was observed in 78% of primary NPC tissues. No mutations, assessed by PCR-SSCP and DNA sequencing, were found in the promoter region and exon 1 of LARS2 in NPC tissues, whereas HD was detected in 28% of NPC specimens at the LARS2 locus. In addition, hypermethylation of LARS2 was found in 64% of NPC samples but only in 12.5% of NP biopsies. Our data indicate that inactivation of LARS2 by both genetic and epigenetic mechanisms may be a common and important event in the carcinogenesis of NPC.

Effects of transketolase-like gene TKTL1 on occurrence and metastasis of human nasopharyngeal carcinoma

To investigate the effects of transketolase-like gene TKTL1 on the occurrence and metastasis of human nasopharyngeal carcinoma (NPC). Real-time PCR was used to determine the mRNA expression levels of transketolase gene family (TKT, TKTL1, and TKTL2) in the 65 biopsy specimens of human nasopharyngeal carcinoma, 9 at stage I, 15 at stage II, 16 at stage III, 13 at stage IVA, and 12 at stage IVB, 42 with metastasis and 232 without metastasis, and 9 biopsy specimens of chronic nasopharyngitis. The TKL activity level of the NPC tissues was 21.6 +/- 2.8, significantly higher than that of the chronic nasopharyngitis tissues (6.2 +/- 1.3, P < 0.01). The TKL activity level of the NPC tissues with metastasis was 26.5 +/- 3.2, significantly higher than that of the NPC tissues without metastasis (17.6 +/- 2.1, P < 0.01). There was no significant difference in the expression levels of TKT and TKTL2 genes between the human NPC and chronic nasopharyngitis tissues (both P > 0.05). The expression level of TKTL1 gene in the NPC tissues was 5.25 +/- 0.32, significantly higher than that in the chronic nasopharyngitis tissues (0.98 +/- 0.11, t = 6.23, P < 0.01), and the expression level of TKTL1 gene in the NPC tissues with lymph node metastasis was 5.86 +/- 0.38, significantly higher than that in the NPC tissues without lymph node metastasis (4.18 +/- 0.22, t = 3.28, P < 0.01). TKTL1 may play an important role in the occurrence and metastasis of human NPC and become a potential target for novel anti-cancer therapy.

Genetic and Epigenetic Alterations of LTF at 3p21.3 in Nasopharyngeal Carcinoma

To investigate the roles of lactotransferrin gene (LTF, also referred to as the lactoferrin gene, LF), located at 3p21.3 within the common minimal deletion region, in the pathogenesis of nasopharyngeal carcinoma (NPC), we first detected its expression level in 33 primary NPC tissues and 15 chronic nasopharyngitis tissues. Absent expression or downregulation of LTF were observed in 76% (25 of 33) of primary NPC tissues. We further found that 25% (5 of 20) of NPC specimens had loss of heterozygosity (LOH) at the LTF locus. LTF mutation assessed by polymerase chain reaction single-strand conformation polymorphism (PCR-SSCP) and DNA sequencing was noted in 30% (6 of 20) of primary NPC tissues. In addition, hyper-methylation of LTF promoter region was found in 63.6% (21 of 33) of primary NPC samples but not in chronic nasopharyngitis tissues. The LTF transcripts in NPC cell lines increased upon treatment with the demethylation compound, 5-aza-2-deoxycytidine. In conclusion, our data indicate that two-hit silencing of LTF through genetic and epigenetic changes may be a common and important event in the carcinogenesis of NPC.

Amplification and specific expression of T-bet gene in nasal NK/T cell lymphoma

To investigate the specific genetic alterations in nasal NK/T cell lymphoma (N-NK/T-L) and the significance thereof. Restriction landmark genomic scanning (RLGS) was performed on the specimen of a case of N-NK/T-L and the peripheral blood leukocytes of the same case. The RLGS image was analyzed with the Virtual genome scan (VGS) software so as to discover abnormality of T-bet gene. The discovered abnormal gene underwent cloning and preparation of probes. Southern blotting and dot blotting were performed on 3 cases of fresh N-NK/T-L tumor tissues and the genome of the case of peripheral blood lymphocytes. The expression of the T-bet (T-box expressed in T cell) gene in the tissue sections of 20 cases of N-NK/T-L, 17 cases of B cell lymphoma (BCL), 3 cases of normal spleen, and 5 cases of chronic nasopharyngitis was detected by in situ hybridization. RLGS combined with VGS revealed a genomic alteration in the T-bet gene and consequent Southern and dot blotting confirmed this genomic alteration in the N-NK/T-L cells. In situ hybridization showed that the T-bet mRNA expression rate of the N-NK/T-L cells was 90.0% (18/20), significantly higher than that of the BCL (11.8%, 2/17, P < 0.01). T-bet mRNA expression was not detected in the normal spleen and chronic nasopharyngitis tissues. The amplification and over-expression of the T-bet gene may play a role in the development of N-NK/T-L. The potential value of over-expression of T-bet gene in diagnosis of N-NK/T-L is worth further investigating.

Frequent Hypermethylation of RASSF1A, TSLC1, High Viral Load of Epstein-Barr Virus DNA in Nasopharyngeal Carcinoma, Matched Tumor-Adjacent Tissues

We examined the promoter hypermethylation of tumorsuppressor genes RASSF1A, TSLC1, quantitated EBV DNA load in nasopharyngeal carcinoma (NPC) tissues (T tissues), matched tumor-adjacent tissues outside 0.5 cm (P tissues), outside 1.0 cm (Z tissues) to evaluate the role of promoter hypermethylation of RASSF1A, TSLC1 as well as viral load in the pathogenesis of NPC. Methylation-specific polymerase chain reaction (PCR) for RASSF1A, TSLC1, quantitative real-time PCR analysis of EBV DNA were performed on matched T, P, Z tissues (n = 28) as well as chronic nasopharyngitis tissues (n = 8). Hypermethylated RASSF1A was frequently detected in the T (82%), P tissues (75%), but less frequently in Z tissues (46%). The average quantities of EBV DNA (copies/μg DNA) in matched T, P, Z tissues were 673,000, 90,000, 7000. The differences of promoter hypermethylation of RASSF1A, EBV viral load among T, P, Z tissues were statistically significant, with more frequent methylation, higher viral load detected when tissues examined were nearer to the NPC tissues. Our results suggest that aberrant hypermethylation of RASSF1A, high EBV load might be important events in NPC pathogenesis, they may be useful molecular diagnostic markers for this cancer.

Quantitative analysis of Epstein-Barr virus DNA in plasma and peripheral blood cells in patients with nasopharyngeal carcinoma

To quantitative analysis of Epstein-Barr virus (EBV) DNA levels in plasma, peripheral blood cells (PBCs) and tumor tissue in nasopharyngeal carcinoma (NPC), to investigate the relationship between EBV-DNA levels and clinical parameters. Blood of 150 primary NPC and 49 corresponding tumor tissues, 47 nasopharyngitis tissues and blood of 75 controls were entered this investigation. Plasma and PBCs were isolated for quantitative detection of EBV-DNA by using real-time quantitative PCR (RQ-PCR). The paraffin-embedded tissue sections were conducted to quantitative detection of EBV-DNA, and EBER1 in situ hybridization (ISH) for calculating the percentage of positive cells on the tissue section. Plasma EBV-DNA levels and detecting rate in NPC before treatment (median 82 500 copies/ml, 92%) were significantly higher than that in NPC after treatment (median 0 copy/ml, 19%) and in controls (median 0 copy/ml, 12%) (P < 0.05), whereas there was no significant difference between NPC after treatment and controls (P > 0.05). There was no significant difference of PBCs EBV-DNA load and detecting rate in NPC before (0 copy/actin, 24%) and after treatment (0 copy/actin, 14%), as well as in controls (0 copy/actin, 16%) (P > 0.05). Plasma EBV-DNA level was not correlated to PBCs EBV-DNA load in NPC before (P = 0.92) and after treatment (P = 0.27), and controls (P = 0.74). EBV-DNA level (27.8 copies/actin) in NPC tumor tissues was significantly higher than that in nasopharyngitis (0 copy/actin) (P < 0.05), and was positively correlated to the ratio of EBER1 positive cells to total cells on the NPC section. In NPC patients, plasma EBV-DNA level was significantly increased in TNM stage I (2500 copies/ml), II (32 590 copies/ml), III (86 000 copies/ml) and IV (166 200 copies/ml), whereas there was no significantly difference of PBCs EBV-DNA loads in difference stages of NPC. Plasma EBV-DNA level is a more sensitive and reliable biomarker than PBCs EBV-DNA loads for reflection the tumor volumes in NPC patients. Plasma EBV-DNA detection will improve TNM staging in NPC clinical practice on molecular level.

Detection and its implication of heat stress protein 27 and P21 in nasopharyngeal carcinoma.

To study the expression of heat stress protein 27 (HSP27) and P21 in nasopharyngeal carcinoma (NPC) tissue, and to evaluate the significance of both HSP27 and P21 in the pathogenesis, development and prognosis of NPC. Indirect immunofluorescence method combined with SABC was applied. Our results showed that (1) the positive rates of HSP27 and P21 expressed in NPC tissue in 36 cases were 88.9% and 94.4%; (2) while in 10 hyperplastic nasopharyngitis tissues, the positive rate of HSP27 and P21 were both 5; (3) all the 5 normal tissues were negatively stained. It is obvious that a co-expressing tendency of HSP27 and P21 could be identified, and it was associated with the degree of malignancy and the clinical stage of NPC. It is concluded that the positive expression of HSP27 and P21 may have clinical significance in the evaluation of the occurring, development and prognosis of NPC, and in NPC treatment.