Co-expression of p53 and bcl-2 may correlate to the presence of epstein-barr virus genome and the expression of proliferating cell nuclear antigen in nasopharyngeal carcinoma

Epstein-Barr virus infection mediated TP53 and Bcl-2 expression in nasopharyngeal carcinoma pathogenesis

Epstein Barr virus (EBV) stimulates neoplastic transformation of nasopharyngeal epithelial cells through various molecular mechanisms, predominantly affecting inactivation of tumor-suppressor genes and activation of oncogenes. EBV infection is a major risk factor for nasopharyngeal carcinoma (NPC), yet its role in the carcinogenesis is not clear. EBV infection alters the expression of antiapoptotic proteins and tumor suppressor proteins. Therefore, this study investigated the correlation between EBV infection status with B cell lymphoma-2 (Bcl-2) and TP53 protein expression amongst laryngeal and nasopharyngeal cancer cases. This study was performed using 22 nasopharyngeal and 11 laryngeal cancer cases. EBV infection status, TP53 and Bcl-2 protein expression was studied using immunohistochemistry. The majority of the laryngeal cancer cases exhibited a poor prognosis and presented low Bcl-2 expression. A total of 22.7% cases were infected with EBV in the NPC cases. Upregulated TP53 expression was associated with EBV infection in the NPC cohort, and EBV infection was correlated with TP53 upregulation in the patients with NPC, suggesting mutual regulation between TP53 and EBV.

Microarray Analysis of Novel Genes Involved in Nasopharyngeal Carcinoma

Nasopharyngeal carcinoma (NPC) is an epithelial cancer associated with Epstein-Barr virus. Despite NPC is a widespread malignancy, little is known about association of tumor growth with gene expression. This study is aimed to detect potential genes implicated in the molecular mechanism of NPC. To this end, we downloaded GSE12452, GSE53819 and GSE64634 libraries from GEO database. GEO2R interface was used to search for the differentially expressed genes (DEGs) with R and LIMMA software, which yielded the Venn diagrams of co-expressed genes. The GO and KEGG databases were used to find DEGs with up- and down-regulated expression. Then Cytoscape software constructed and analyzed the protein-protein interaction (PPI) networks corresponding to revealed DEGs, thereupon the hub genes were analyzed in tissues and cell cultures with qRT-PCR. This combined analysis yielded 483 co-expressed DEGs, including 258 DEGs with up-regulated expression and 225 DEGs with down-regulated expression, which are mainly implicated in the cell cycle, DNA replication, as well as in formation and maturation of extracellular vesicles and exosomes. In comparison with normal nasopharyngeal tissues of healthy persons, expression of CDK1 gene was down-regulated in NPC tissue; in contrast, expression of PCNA, MAD2L1, PRC1, CENPF, and ZWINT genes was up-regulated in the tumor. The genes PCNA, MAD2L1, and ZWINT were differently expressed in EBV+ and EBV- nasopharyngeal carcinoma cells. The use of bioinformatic methods to reveal and analyze the differences in gene expression between the normal and NPC tissues opens the vista to further progress in deciphering the molecular mechanisms of NPC formation and development.

Epstein-Barr virus induces morphological and molecular changes in thyroid neoplastic cells

Although the evolution of differentiated thyroid cancer (DTC) is usually indolent, some tumors grow fast, metastasize, and may be fatal. Viruses have been associated with many human tumors, especially the Epstein-Barr virus (EBV), which shows a high viral load in DTC. In order to evaluate the ability of the virus to cause morphological and molecular changes in neoplastic thyroid cell lines TPC-1, BCPAP, and 8505C, a viral adaptation was performed for the analysis of EBV cytopathic effect (CPE), viral kinetics and gene expression analysis of oncogenes KRAS, NRAS, HRAS, and TP53. Comparison of inoculated cells with non-inoculated control cells showed that all tumor cell lines were permissive to the virus. The virus caused CPE in the TPC-1 and 8505C, but not in BCPAP cells. Viral kinetic was similar in both BCPAP and 8505C with a point of eclipse at 24 h post infection. TPC-1 cell line displayed a decreasing growth curve, with highest viral load right after inoculation, which decreased over time. There was hyperexpression of TP53 and NRAS in BCPAP cell (p = 0.012 and p = 0.0344, respectively). The 8505C cell line presented NRAS hyperexpression (p = 0.0255), but lower TP53 expression (p = 0.0274). We concluded that neoplastic thyroid cell lines are permissive to EBV that the virus presents different viral kinetic patterns in different cell lines and produces a CPE on both well-differentiated and undifferentiated thyroid cell lines. We also demonstrated that EBV interferes in oncogene expression in thyroid neoplastic cell lines, suggesting that these effects could be related to different tumor progression patterns.

Association of Protein Expression p53 Mutants with Regional Lymph Gland Status on type III Carcinoma Nasofaring Patients

Nasopharyngeal carcinoma (NPC) is a malignant disease originating from the nasopharyngeal epithelial cells. The molecular mechanism of cancer occurrence is a change in the oncogene and tumor suppressor genes. One of the tumor suppressor genes that mutate in cancer cells is the mutant p53 gene. One of nasopharyngeal carcinoma progression is determined by the status of regional lymph gland. The enormous regional lymph node has a poor prognosis. To analyze the expression of the mutant p53 protein in Nasopharyngeal carcinoma (NPC) that correlated with regional lymph gland status (N) as a clinical manifestation. Expression of mutant p53 protein from NPC tissue paraffin block with immunohistochemical cracking technique was using monoclonal rabbit Anti Human p53 clone 318-6-11 (Dako, North America, Inc., 6392 Via Real Carpinteria, CA 93013 USA), microscope light binoculars was assessed visually by an Anatomical Pathology Consultant. Positive expression of p53 mutants was obtained 57.58% from all the sample in N0 by 0 subjects, N1 was 6 subjects, N2 was 7 subjects, and N3 was 7 subjects. The results of Mann-Whitney U test was p = 0.706, then there was no significant (p > 0.05) correlation between positive expression of p53 protein in type III WHO NPC with the regional lymph gland were N0, N1, N2, and N3. There was no significant between expression protein p53 mutants' regional and lymph gland in type III WHO NPC.

Tumor Suppressor p53 Stimulates the Expression of Epstein-Barr Virus Latent Membrane Protein 1

Epstein-Barr virus (EBV) is associated with multiple human malignancies. EBV latent membrane protein 1 (LMP1) is required for the efficient transformation of primary B lymphocytes in vitro and possibly in vivo The tumor suppressor p53 plays a seminal role in cancer development. In some EBV-associated cancers, p53 tends to be wild type and overly expressed; however, the effects of p53 on LMP1 expression is not clear. We find LMP1 expression to be associated with p53 expression in EBV-transformed cells under physiological and DNA damaging conditions. DNA damage stimulates LMP1 expression, and p53 is required for the stimulation. Ectopic p53 stimulates endogenous LMP1 expression. Moreover, endogenous LMP1 blocks DNA damage-mediated apoptosis. Regarding the mechanism of p53-mediated LMP1 expression, we find that interferon regulatory factor 5 (IRF5), a direct target of p53, is associated with both p53 and LMP1. IRF5 binds to and activates a LMP1 promoter reporter construct. Ectopic IRF5 increases the expression of LMP1, while knockdown of IRF5 leads to reduction of LMP1. Furthermore, LMP1 blocks IRF5-mediated apoptosis in EBV-infected cells. All of the data suggest that cellular p53 stimulates viral LMP1 expression, and IRF5 may be one of the factors for p53-mediated LMP1 stimulation. LMP1 may subsequently block DNA damage- and IRF5-mediated apoptosis for the benefits of EBV. The mutual regulation between p53 and LMP1 may play an important role in EBV infection and latency and its related cancers.IMPORTANCE The tumor suppressor p53 is a critical cellular protein in response to various stresses and dictates cells for various responses, including apoptosis. This work suggests that an Epstein-Bar virus (EBV) principal viral oncogene is activated by cellular p53. The viral oncogene blocks p53-mediated adverse effects during viral infection and transformation. Therefore, the induction of the viral oncogene by p53 provides a means for the virus to cope with infection and DNA damage-mediated cellular stresses. This seems to be the first report that p53 activates a viral oncogene; therefore, the discovery would be interesting to a broad readership from the fields of oncology to virology.

Prevalence and significance of plasma Epstein-Barr Virus DNA level in nasopharyngeal carcinoma

Epstein-Barr virus (EBV) DNA has been recognized as a promising tumor marker for nasopharyngeal carcinoma (NPC). This study aims to demonstrate the prevalence of plasma EBV DNA and its temporal correlation with treatment outcomes in the modern era. A total of 204 patients with Stage I-IVB NPC treated with intensity-modulated radiotherapy (IMRT) were enrolled. Quantitative plasma EBV DNA measurement was performed before treatment (pre-IMRT), on the fifth week of radiation (mid-IMRT), at 3 months after radiation (post-IMRT), then every 6 months until disease relapse. Progression-free survival (PFS) and overall survival (OS) were analyzed using the Kaplan-Meier method. Plasma EBV DNA was detected in 110 patients (53.9%), with a median pre-IMRT EBV DNA level of 8005 copies/ml. Significant correlation was noted between pre-IMRT EBV DNA level and disease stage, but not between pre-IMRT EBV DNA level and World Health Organization classification. With a median follow-up time of 35.1 months, the 3-year PFS and OS rates were higher in the group with undetectable pre-IMRT EBV DNA level compared with in the group in which it was detectable. When classified according to disease stage and pre-IMRT EBV DNA, patients with early disease and detectable pre-IMRT EBV DNA experienced poorer survival than those with locally advanced disease and undetectable pre-IMRT EBV DNA. According to the dynamic changes in EBV DNA level between pre-IMRT and mid/post IMRT, survival was significantly higher in patients who achieved an undetectable level following treatment. On multivariate analysis, post-IMRT EBV DNA level was the strongest predictor of all treatment outcomes (P < 0.001). Our study demonstrated the clinical significance of the plasma EBV DNA level at specific time points, as well as of the dynamic changes in the EBV DNA level. Disappearance of plasma EBV DNA after treatment was associated with better survival.

Microarray Expression Profiling of Long Non-Coding RNAs Involved in Nasopharyngeal Carcinoma Metastasis

Increasing evidence has demonstrated a significant role for long non-coding RNAs (lncRNAs) in tumorigenesis. However, their functions in nasopharyngeal carcinoma (NPC) metastasis remain largely unknown. In this study, a model comparing high and low metastatic NPC cell lines (5-8F vs. 6-10B and S18 vs. S26) was constructed to determine the expression profile of lncRNAs using the microarray analysis, and we found 167 lncRNAs and 209 mRNAs were differentially expressed. Bioinformatic analysis indicated that the dysregulated mRNAs participated in important biological regulatory functions in NPC. Validation of 26 significantly dysregulated lncRNAs by qRT-PCR showed the expression patterns of 22 lncRNAs were in accordance with the microarray data. Furthermore, the expression level of ENST00000470135, which was the most upregulated lncRNA in high metastatic cell lines, was significantly higher in NPC cell lines and tissues with lymph node metastasis (LNM) and knocking down ENST00000470135 suppressed the migration, invasion and proliferation of NPC cells in vitro. In conclusion, our study revealed expression patterns of lncRNAs in NPC metastasis. The dysregulated lncRNAs may act as novel biomarkers and therapeutic targets for NPC.

Lymphoepithelioma-like carcinoma of ureter-a rare case report and review of the literature

Lymphoepithelioma-like carcinoma (LELC) is best known to occur in the nasopharynx. When LELC occurs in the urinary tract, this extremely rare neoplasm most commonly affects the bladder but has also been reported in the renal pelvis, ureter, prostate [1], and urethra [2]. We present a case of LELC arising in the right proximal ureter of a 64-year-old male patient with hydronephrosis and nausea. Computed tomography demonstrated right ureter tumor. On biopsy, the patient was diagnosed with infiltrating urothelial carcinoma. An operation consisting of right nephroureterectomy and bladder cuff removal was carried out. The pathologic examination showed pure subtype of LELC, pT3N0. Unlike lymphoepithelioma in the nasopharynx, immunohistochemical analysis of this urinary LELC was negative for the Epstein-Barr virus. No disease progression was noted at 6 months' follow-up. Only eight previous cases of LELC involving the ureter have been reported, and a review of the available literature and a summary of ureter cases are presented here. This is the first report of a ureteral LELC case and third urothelial LELC cases [3] in Taiwan.

[North African and Southeast Asian nasopharyngeal carcinomas: between the resemblance and the dissemblance]

Nasopharyngeal carcinoma (NPC) is an unusual head and neck cancer because of its unequal geographical distribution and its consistent association with the Epstein-Barr virus (EBV). This malignant tumor poses a serious public health problem in many countries, especially in Southeast Asia and North Africa where the recorded incidence are highest. During the past decade, a growing number of studies were undertaken to define the molecular basis of NPC. However, the analysis of several clinical and biological parameters of North African and Southeast Asian NPCs has shown notable differences, suggesting that they could result from a distinct combination of etiological factors. One intriguing characteristic of North African NPC, concerns its bimodal age distribution with a secondary peak of incidence in the range of 15-25 years, not observed in Asian NPC. In this juvenile form of NPC, immuno-histochemistry assay has shown that the two key proteins controlling the apoptotic-survival balance p53 and Bcl-2 are less frequently expressed whereas the transmembrane tyrosine-kinase receptor c-kit and the main EBV oncoprotein LMP1 were more abundant. In addition, the EBV serological alterations are less informative for the diagnosis of the juvenile compared to the adult form. In addition, most North African NPCs contain EBV strains with genetic polymorphisms distinct from those described in the Southeast Asia series (predominance of F, D, H1-H2, XhoI+ and f, C, H, XhoI- respectively). In contrast, studies relating on tumor chromosomal alterations or aberrant promoter methylation result in data very similar to those obtained from the Southeast Asia series, supporting the concept of a common molecular basis for all NPC regardless of patient geographic origin.

NOLC1, an enhancer of nasopharyngeal carcinoma progression, is essential for TP53 to regulate MDM2 expression

Nasopharyngeal carcinoma (NPC) is one of the most common cancers among Chinese living in South China, Singapore, and Taiwan. At present, its etiological factors are not well defined. To identify which genetic alterations might be involved in NPC pathogenesis, we identified genes that were differentially expressed in NPC cell lines and normal nasomucosal cells using subtractive hybridization and microarray analysis. Most NPC cell lines and biopsy specimens were found to have higher expression levels of the gene encoding nucleolar and coiled-body phosphoprotein 1 (NOLC1) as compared with normal cells. Severe combined immunodeficiency mice bearing NPC xenografts derived from NOLC1-short hairpin-RNA-transfected animals were found to have 82% lower levels of tumor growth than control mice as well as marked tumor cell apoptosis. Measuring the expression levels of genes related to cell growth, apoptosis, and angiogenesis, we found that the MDM2 gene was down-regulated in the transfectants. Both co-transfection and chromatin immunoprecipitation experiments showed that tumor protein 53-regulated expression of the MDM2 gene requires co-activation of NOLC1. These findings suggest that NOLC1 plays a role in the regulation of tumorigenesis of NPC and demonstrate that both NOLC1 and tumor protein 53 work together synergistically to activate the MDM2 promoter in NPC cells.

Lymphoepithelioma-like hepatocellular carcinoma: A case report and a review of the literature

Lymphoepithelioma is a particular form of undifferentiated carcinoma, characterized by a prominent lymphoid stroma, originally described in the nasopharynx. Lymphoid stroma-rich carcinomas arising in other organs have been termed lymphoepithelioma-like carcinoma (LELC). In the liver, primary LELCs are very rare, and the majority has been identified as cholangiocarcinomas. Here a rare case of lymphoepithelioma-like hepatocellular carcinoma (HCC) is described. A 47-year old woman presented with abdominal pain. Ultrasonography revealed a liver nodule, 2.2 cm in diameter, localized in the right lobe, adjacent to the gallbladder. Viral markers for hepatic B virus (HBV), hepatic C virus (HCV) and Epstein-Barr virus (EBV) were negative. The nodule was hypoechogenic. The patient underwent surgery, with resection of the nodule. Histology showed hepatocellular carcinoma, characterized by a prominent lymphoid infiltrate. At immunocytochemistry, tumor cells were reactive for Hep Par1 and glypican 3. Immunophenotyping of tumor infiltrating lymphocytes evidenced the predominance of CD8+ cytotoxic suppressor T cells. The postoperative clinical outcome was favorable and the patient was recurrence-free 15 mo after resection. This case, to the best of our knowledge, is the first reported non EBV and non cirrhosis-associated lymphoepithelioma-like hepatocellular carcinoma. The association between the lack of EBV infection, the absence of cirrhosis, a “cytotoxic profile” of the inflammatory infiltrate and a good prognosis could identify a variant of lymphoepithelioma-like HCC with a favorable clinical outcome.

Nasopharyngeal carcinoma--review of the molecular mechanisms of tumorigenesis

Nasopharyngeal carcinoma (NPC) is a head and neck cancer rare throughout most of the world but common in certain geographic areas, such as southern Asia. While environmental factors and genetic susceptibility play important roles in NPC pathogenesis, the Epstein-Barr virus in particular has been implicated in the molecular abnormalities leading to NPC. There is upregulation of cellular proliferation pathways such as the Akt pathway, mitogen-activated protein kinases, and the Wnt pathway. Cell adhesion is compromised due to abnormal E-cadherin and beta-catenin function. Aberrations in cell cycle are due to dysregulation of factors such as p16, cyclin D1, and cyclin E. Anti-apoptotic mechanisms are also upregulated. There are multiple abnormalities unique to NPC that are potential targets for novel treatments.

Lymphoepithelioma-like carcinoma of the urinary tract: a clinicopathological study of 30 pure and mixed cases

We studied 28 cases of lymphoepithelioma-like carcinoma of the bladder, one case in the renal pelvis, and one in the urethra. The mean age of the patients was 67.6 years with 21 (70%) males. Seventeen cases (56.7%) were pure with the remaining mixed with other patterns of carcinoma, including invasive urothelial carcinoma (n=10), invasive adenocarcinoma (n=3), and squamous cell carcinoma (n=2). The surface demonstrated carcinoma in situ (CIS) in six cases, noninvasive high-grade papillary urothelial carcinoma in three cases, and in situ adenocarcinoma in one case. In 19/30 (66%) cases, there was a heavy lymphocytic infiltrate and in the remaining 11/30 (34%) cases a mixed inflammatory infiltrate. None of the 26 cases labeled for EBV-encoded RNA by in situ hybridization. Tumor stages at presentation were: seven cases T1 (23%); 14 cases T2 (47%); seven cases T3 (23%); and two cases T4 (7%). Treatment consisted of radical cystectomy in 13/30 cases (43%); partial cystectomy in 4/30 cases (13%); nephrectomy in one case (3%), and transurethral resection often followed by radiation or chemotherapy in 12/30 (40%) cases. The mean follow up for patients without progression was 31 months. Eight of 27 cases with follow-up (30%) cases had tumor recurrence, with seven patients having metastases. In cases treated with cystectomy, the 5-year actuarial recurrence-free risk was 59% (62 and 57%, for pure and mixed cases, respectively). Lymphoepithelioma-like carcinoma, whether in pure or mixed form, has a similar prognosis to ordinary urothelial carcinoma when treated by cystectomy. Of the three pure cases treated by chemotherapy, two were free of disease at 4 and 65 months and the third had recurrent disease at 17 months. Given the association of lymphoepithelioma-like carcinoma with urothelial carcinoma in 47% of our cases and its propensity for multifocality, partial cystectomy would typically be ill advised for lymphoepithelioma-like carcinoma.

Prognostic Significance of the Epstein-Barr Virus, p53, Bcl-2, and Survivin in Nasopharyngeal Cancer

PURPOSE

Nasopharyngeal cancer (NPC) is a malignant epithelial carcinoma which is intimately associated with EBV. The latent presence of EBV affects the function of p53, Bcl-2, and survivin. We thus investigated the relationship between EBV status, p53, Bcl-2, and survivin in biopsy specimens from patients with primary NPC.

EXPERIMENTAL DESIGN

Archival formalin-fixed, paraffin-embedded NPC biopsies were evaluated in 80 patients treated with curative radiation from a single institution. The presence of EBV was determined using EBER in situ hybridization, whereas p53, Bcl-2, and survivin were assessed using immunohistochemistry.

RESULTS

The majority of NPC specimens in this patient cohort were EBER-positive (64 of 78, or 82%), which in turn, was significantly associated with ethnicity (P = 0.0007), and WHO subtype 2A/2B (P = 0.04). EBER-positive tumors were also associated with p53 (P = 0.002), Bcl-2 (P = 0.04), and nuclear survivin (P = 0.03) expression. Patients with EBER-positive NPC fared better, with a 10-year overall survival of 68% versus 48% for EBER-negative patients (P = 0.03). For nuclear survivin, patients with either low or high nuclear survivin fared worse than patients with intermediate survivin expression (P = 0.05), suggesting that there is an optimal proportion of survivin-expressing cells for best function and clinical outcome.

CONCLUSIONS

With an extended median follow-up time of 11.4 years, EBV status remains a strong predictor for overall survival in NPC. EBV-positive NPC has strong molecular associations with p53, Bcl-2, and survivin expression. Furthermore, we provide clinical data revealing the potentially dual nature of survivin in predicting clinical outcome.

Systemic Bcl-2 antisense oligodeoxynucleotide in combination with cisplatin cures EBV+ nasopharyngeal carcinoma xenografts in SCID mice

Nasopharyngeal carcinoma (NPC) is causally linked to Epstein-Barr virus (EBV), and the EBV oncoprotein, latent membrane protein 1 (LMP-1), is expressed in the majority of NPCs. LMP-1 upregulates antiapoptotic genes, including bcl-2, and Bcl-2 protein is overexpressed in NPC. Given the antiapoptotic and chemoprotective effects of Bcl-2, it represents a rational therapeutic target in NPC. We have investigated the antitumor and chemosensitizing effects of the Bcl-2 antisense oligodeoxynucleotide G3139 (oblimersen, Genasense) in NPC. For these studies, we used the C666-1 line, a stably infected NPC-derived line that co-expresses LMP-1 and Bcl-2. We have shown that G3139 treatment of C666-1 in vitro caused sequence-dependent suppression of Bcl-2 protein, inhibition of cell growth and enhanced sensitivity to cisplatin (CDDP), as measured by increased antiproliferative and apoptotic effects. In vivo, G3139 treatment (25 mg/kg every 3 days x 5 doses) delayed engraftment and significantly inhibited growth of established C666-1 xenografts in SCID mice compared to control oligo-treated animals. However, G3139 alone did not prevent engraftment or cure established tumors in any animals. In contrast, G3139 treatment (25 mg/kg every 3 days x 5 starting on day 7) in combination with CDDP (8 mg/kg on day 14) completely abrogated tumor engraftment in 80% of animals compared to CDDP (0%) or CDDP + control oligo (0%). When treatment was delayed until tumor was established, G3139 in combination with CDDP significantly inhibited tumor growth compared to CDDP or CDDP + control oligo, and cured 69% animals with established tumors. No animals treated with G3139, CDDP or CDDP + control oligo were cured. Tumor burden and response to treatment correlated with EBV DNA load in serum, measured by real-time PCR. Western blots of tumor extracts obtained during oligo treatment showed that Bcl-2 levels were significantly decreased in G3139-treated animals. Our studies have demonstrated that the Bcl-2 antisense oligodeoxynucleotide, G3139, has proapoptotic effects in C666-1, and in combination with CDDP, is curative in C666-1 NPC xenograft tumors in vivo. The sequence-dependency of these effects is consistent with an antisense mechanism. These studies suggest that Bcl-2 may represent a biologically relevant target for the development of novel combinatorial therapies for NPC.

The prognostic value of proliferating cell nuclear antigen (PCNA) and p53 protein expression in patients with advanced nasopharyngeal carcinoma

CONCLUSION

p53 protein and proliferating cell nuclear antigen (PCNA) were not ideal prognostic indicators in advanced nasopharyngeal carcinoma (NPC). Further investigation in searching for other potential biomarkers is needed to enhance the prediction of treatment outcome.

OBJECTIVE

To assess the prognostic significance of p53 protein and PCNA expression in patients with advanced NPC.

PATIENTS AND METHODS

This study included 46 patients with advanced NPC who had received treatment and regular follow-up for at least 5 years. We used immunohistochemistry (IHC) staining to assess p53 protein expression and PCNA labeling index, and correlate them with pathological subtypes, TNM stage, the presence of locoregional recurrence, and 5-year survival rate.

RESULTS

p53 nuclear staining was positive in 32 patients (69.6%). All cases had positive PCNA nuclear staining with labeling index (LI) ranging from 6.5% to 92.9% (mean 53.4%). Only advanced T stage was found to be associated with high PCNA LI. Overexpression of p53 and PCNA LI had no impact on 5-year survival in this study group.

Correlation between proliferating cell nuclear antigen and p53 protein expression and 5-year survival rate in nasopharyngeal carcinoma

PURPOSE

To assess the prognostic significance of p53 protein and proliferating cell nuclear antigen (PCNA) expression in nasopharyngeal carcinoma.

MATERIALS AND METHODS

This study included 79 patients who had received treatment and regular follow-up for at least 5 years at a single institute. We used immunohistochemistry staining to assess p53 protein expression and PCNA labeling index (LI). Analyses were conducted on the association between each of the 2 biomarkers and pathological subtypes, TNM stage, the presence of locoregional recurrence, and 5-year survival rate.

RESULTS

p53 protein nuclear staining was positive in 49 patients (62%). The mean PCNA LI was 55.6%, ranging from 3.35% to 92.9%. High PCNA LI (>55.6%) might contribute to higher 5-year survival rate, but it did not reach statistical significance (P = .09). Positive p53 protein staining and low PCNA LI were associated with the presence of locoregional recurrence. No statistical significance was found between p53 protein expression and PCNA LI and pathological subtypes and TNM stage.

CONCLUSION

p53 protein and PCNA LI were not an ideal prognostic indicator in predicting 5-year survival rate in nasopharyngeal carcinoma. Future work will direct toward searching for other potential biomarkers with the hope to reinforce prediction of prognosis.

Absence of p53 alterations in nasopharyngeal carcinoma Spanish patients with Epstein-Barr virus infection

The objective of this study was to analyse the relationships between the Epstein-Barr virus (EBV) infection and the molecular abnormalities of the p53 oncoprotein in the nasopharyngeal carcinoma (NPC). Fifty-five NPC paraffin samples from a group of Spanish patients with EBV demonstrated presence by nested-PCR and non-isotopic in situ hybridisation, were analysed for p53 expression using immunohistochemistry. The positive samples by immunohistochemistry were studied for p53 gene alterations in the exon 5 by single strand conformation polymorphism (SSCP). Among the 55 specimens, 14 (25.5%) showed expression of p53 protein. All these positive samples corresponded to the late stage of the tumour. Of the 14 samples, p53 gene alterations were found only in three cases using SSCP. These results indicate that the p53 mutations are an infrequent event in NPC in Spanish patients needing exogenous factors as the EBV infection for the development of this malignancy.

Pathogenic roles for Epstein-Barr virus (EBV) gene products in EBV-associated proliferative disorders

Epstein-Barr virus (EBV) is associated with a still growing spectrum of clinical disorders, ranging from acute and chronic inflammatory diseases to lymphoid and epithelial malignancies. Based on a combination of in vitro and in vivo findings, EBV is thought to contribute in the pathogenesis of these diseases. The different EBV gene expression patterns in the various disorders, suggest different EBV-mediated pathogenic mechanisms. In the following pages, an overview of the biology of EBV-infection is given and functional aspects of EBV-proteins are discussed and their putative role in the various EBV-associated disorders is described. EBV gene expression patterns and possible pathogenic mechanisms are discussed. In addition, expression of the cellular genes upregulated by EBV in vitro is discussed, and a comparison with the in vivo situation is made.

Prognostic significance of the proline form of p53 codon 72 polymorphism in nasopharyngeal carcinoma

OBJECTIVES/ HYPOTHESIS

An important tumor suppressor gene, p53, plays a role in the regulation of cell progression and prevention of carcinogenesis. Mutated p53 is related to cell progression and malignancy. We aimed to evaluate the association between nasopharyngeal carcinoma and p53 polymorphism.

STUDY DESIGN

Case control study.

METHODS

All individuals were divided into two groups: nasopharyngeal carcinoma (n = 50) and non-nasopharyngeal carcinoma groups (n = 59). Their p53 codon 72 polymorphisms (arginine [Arg] homozygotes, heterozygotes, proline [Pro] homozygotes) were detected by polymerase chain reaction. Associations between nasopharyngeal carcinoma and p53 polymorphism were evaluated.

RESULTS

Distributions of various p53 polymorphisms significantly differed between the two groups. We noted a dominant presentation of Pro homozygotes in the nasopharyngeal carcinoma population over that in the non-nasopharyngeal carcinoma population. Proportions of Pro homozygotes and heterozygotes and Arg homozygotes were 32%, 28%, and 40% in the nasopharyngeal carcinoma population and were 13.5%, 44.1%, and 42.4% in the non-nasopharyngeal carcinoma population, respectively.

CONCLUSIONS

An association exists between nasopharyngeal carcinoma and p53 codon 72 polymorphism. The p53 Pro homozygotes are to a higher risk of development of nasopharyngeal carcinoma.