Re-searching nasopharyngeal carcinoma

Nasopharyngeal carcinoma(NPC)has been a focus of medical research for more than 100 years,with significant interest emerging over the last 58 years following the identification of the link between the disease and Epstein-Barr virus(EBV)infection.NPC possesses several distinctive characteristics among human cancers,notably its well-documented global epidemiology,which reveals localized high-incidence regions primarily in Southeast Asia,particularly in the Southern provinces of China near the Pearl river,as well as in Greenland and North Africa.Epidemiological data indicate a marked male predominance,early disease onset,and a nearly 100%prevalence of latent EBV infection in the tumors.Due to lack of consistent pattern of cancer-related mutations in NPC genomes and excessive DNA-methylation in the tumor cells,NPC can be considered"an epigenetic cancer".Despite extensive researches,convincing biological explanations for these unique characteristics remain elusive.Recently,suggestive evidence has been published that specific local variants of EBV may represent major high risk factors.In spite of tumor and virus specific immunity,it has not been possible to use this for improved treatment.Ongoing studies on the role of the local microflora and tumor microenvironment are essential for a comprehensive understanding of host-EBV-tumor interactions.Ultimately,this knowledge aims to enhance diagnosis,disease fractionation,treatment strategies,and potentially prevention of NPC.

Comparing Gross Tumor Volume of Delineation between CT and MRI for Nasopharyngeal Carcinoma

Objective: To study the accuracy between CT and MRI in delineating gross tumor volume (GTV) of nasopharyngeal carcinoma (NPC) in making radiotherapy plan. Methods: The clinical data of 39 cases pathologically proven as nasopharyngeal carcinoma selected from April 2003 to September 2004 were retrospectively analyzed. All were subjected to CT and MR examination one week before treatment. CT scanning was performed with GE Light speed 16, and axial scan was parallel to the OM line routinely from soft palate to the suprasellar cistern. MR scanning was performed by GE Signa super-conducting magnetic resonance imaging system (1.5 Tesla). The standard quadrature head coil was used. Routine axial, sagittal and coronal image with SE sequence were obtained, and FLAIR was used in 10 of 21 cases. Scanned field ranged from the soft palate to the suprasellar cistern. Part of all cases underwent enhanced scanned with Ultravist in CT group or/and GD-DTPA in MR group. All data were analyzed by using the paired-samples t test. Results: The media primary tumor volume (cm3) in CT group and MR group was 32.49±19.91, 29.06±18.75, respectively, and the difference between the two groups were significant (t=5.268, P=0.000). There was significant difference between the two groups in early stage (T1+T2) and advanced stage (T3+T4) by Fuzhou Staging System (t=5.677, P=0.000; t=3.310, P=0.005, respectively). There was significant difference in stage T1, T2, T3 (P=0.005, P=0.001, P=0.004, respectively), and not in stage T4 (P=0.146) between the two groups. Conclusion: MR was more accurate than CT in delineating GTV of NPC, so, is more valuable in making radiotherapy plan.

Prognostic value and predictive threshold of tumor volume for patients with locally advanced nasopharyngeal carcinoma receiving intensity-modulated radiotherapy

Background: Gross target volume of primary tumor(GTV?P) is very important for the prognosis prediction of patients with nasopharyngeal carcinoma(NPC), but it is unknown whether the same is true for locally advanced NPC patients treated with intensity?modulated radiotherapy(IMRT). This study aimed to clarify the prognostic value of tumor volume for patient with locally advanced NPC receiving IMRT and to ind a suitable cut?of value of GTV?P for prognosis prediction.Methods: Clinical data of 358 patients with locally advanced NPC who received IMRT were reviewed. Receiver oper?ating characteristic(ROC) curves were used to identify the cut?of values of GTV?P for the prediction of diferent end?points [overall survival(OS), local relapse?free survival(LRFS), distant metastasis?free survival(DMFS), and disease?free survival(DFS)] and to test the prognostic value of GTV?P when compared with that of the American Joint Committee on Cancer T staging system.Results: The 358 patients with locally advanced NPC were divided into two groups by the cut?of value of GTV?P as determined using ROC curves: 219(61.2%) patients with GTV?P ≤46.4 mL and 139(38.8%) with GTV?P >46.4 mL. The 3?year OS, LRFS, DMFS, and DFS rates were all higher in patients with GTV?P ≤46.4 mL than in those with GTV?P > 46.4 mL(all P < 0.05). Multivariate analysis indicated that GTV?P >46.4 mL was an independent unfavorable prognostic factor for patient survival. The ROC curve veriied that the predictive ability of GTV?P was superior to that of T category(P < 0.001). The cut?of values of GTV?P for the prediction of OS, LRFS, DMFS, and DFS were 46.4, 57.9, 75.4 and 46.4 mL, respectively.Conclusion: In patients with locally advanced NPC, GTV?P >46.4 mL is an independent unfavorable prognostic indi?cator for survival after IMRT, with a prognostic value superior to that of T category.

Ex vivo expansion of tumor-infiltrating lymphocytes from nasopharyngeal carcinoma patients for adoptive immunotherapy

Establishing Epstein-Barr virus (EBV)-specific cytolytic T lymphocytes (EBV-CTLs) from peripheral blood mononuclear cells (PBMCs) for adoptive immunotherapy has been reported in EBV-associated malignancies including Hodgkin's lymphoma and nasopharyngeal carcinoma (NPC). In the current study,we performed ex vivo expansion of tumor-infiltrating lymphocytes (TILs) obtained from NPC biopsy specimens with a rapid expansion protocol using anti-CD3 monoclonal antibody (OKT3), recombinant human interleukin (IL)-2, and irradiated PBMCs from healthy donors to initiate the growth of TILs. Young TIL cultures comprised of more than 90% of CD3+T cells, a variable percentage of CD3+CD8+and CD3+CD4+T cells, and less than 10% of CD3-CD16+natural killer cells, a similar phenotype of EBV-CTL cultures from PBMCs. Interestingly, TIL cultures secreted high levels of the Th1 cytokines, interferon gamma (IFNγ) and tumor necrosis factor-alpha (TNF-α), and low levels of the Th2 cytokines, IL-4 and IL-10. Moreover, young TILs could recognize autologous EBV-transformed B lymphoblast cell lines, but not autologous EBV-negative blast cells or allogeneic EBV-negative tumor cells. Taken together, these data suggest that ex vivo expansion of TILs from NPC biopsy tissue is an appealing alternative method to establish T cell-based immunotherapy for NPC.

Tumor suppressor genes on frequently deleted chromosome 3p in nasopharyngeal carcinoma

Nasopharyngeal carcinoma (NPC) is among the most common malignancies in southern China.Deletion of genomic DNA,which occurs during the complex pathogenesis process for NPC,represents a pivotal mechanism in the inactivation of tumor suppressor genes (TSGs).In many circumstances,loss of TSGs can be detected as diagnostic and prognostic markers in cancer.The short arm of chromosome 3 (3p) is a frequently deleted chromosomal region in NPC,with 3p21.1-21.2 and 3p25.2-26.1 being the most frequently deleted minimal regions.In recent years,our research group and others have focused on the identification and characterization of novel target TSGs at 3p,such as RASSF1A,BLU,RBMS3,and CHL1,in the development and progression of NPC.In this review,we summarize recent findings of TSGs at 3p and discuss some of these genes in detail.A better understanding of TSGs at 3p will significantly improve our understanding of NPC pathogenesis,diagnosis,and treatment.

Impact of primary tumor volume andlocation on the prognosis of patients withlocally recurrent nasopharyngeal carcinoma

Introduction:The properties of a tumor itself were considered the main factors determining the survival of patients with locally recurrent nasopharyngeal carcinoma(NPC)treated with intensity-modulated radiotherapy(IMRT).However,recurrent tumors were mainly evaluated by using the American Joint Committee on Cancer staging system,which was modeled on primary tumors and did not incorporate the tumor volume.This study aimed to investigate the prognostic values of the primary tumor location and tumor volume,and to determine whether evaluating these parameters could improve the current staging system.Methods:Magnetic resonance(MR)images for 229 patients with locally recurrent NPC who underwent IMRT were analyzed retrospectively.Results:The skull base,parapharyngeal space,and intracranial cavity were the most common sites of tumors.There was a difference in the survival between patients with T1 and T2 diseases(77.6%vs.50.0%,P<0.01)and those with T3 and T4 diseases(33.0%vs.18.0%,P=0.04)but no difference between patients with T2 and T3 diseases(50.0%vs.33.0%,P=0.18).Patients with a tumor volume≤38 cm3had a significantly higher survival rate compared with those with a tumor volume>38 cm3(48.7%vs.15.2%,P<0.01).Conclusions:A new staging system has been proposed,with T3 tumors being down-staged to T2 and with the tumor volume being incorporated into the staging,which may lead to an improved evaluation of these tumors.This new system can be used to guide the treatment strategy for different risk groups of recurrent NPC.

Predictive function of tumor burden-incorporated machine-learning algorithms for overall survival and their value in guiding management decisions in patients with locally advanced nasopharyngeal carcinoma

Objective:Accurate prognostic predictions and personalized decision-making on induction chemotherapy(IC)for individuals with locally advanced nasopharyngeal carcinoma(LA-NPC)remain challenging.This research examined the predictive function of tumor burden-incorporated machine-learning algorithms for overall survival(OS)and their value in guiding treatment in patients with LA-NPC.Methods:Individuals with LA-NPC were reviewed retrospectively.Tumor burden signature-based OS prediction models were established using a nomogram and two machine-learning methods,the interpretable eXtreme Gradi-ent Boosting(XGBoost)risk prediction model,and DeepHit time-to-event neural network.The models’prediction performances were compared using the concordance index(C-index)and the area under the curve(AUC).The patients were divided into two cohorts based on the risk predictions of the most successful model.The efficacy of IC combined with concurrent chemoradiotherapy was compared to that of chemoradiotherapy alone.Results:The 1221 eligible individuals,assigned to the training(n=813)or validation(n=408)set,showed significant respective differences in the C-indices of the XGBoost,DeepHit,and nomogram models(0.849 and 0.768,0.811 and 0.767,0.730 and 0.705).The training and validation sets had larger AUCs in the XGBoost and DeepHit models than the nomogram model in predicting OS(0.881 and 0.760,0.845 and 0.776,and 0.764 and 0.729,P<0.001).IC presented survival benefits in the XGBoost-derived high-risk but not low-risk group.Conclusion:This research used machine-learning algorithms to create and verify a comprehensive model inte-grating tumor burden with clinical variables to predict OS and determine which patients will most likely gain from IC.This model could be valuable for delivering patient counseling and conducting clinical evaluations.

Prognostic factors and failure patterns in non-metastatic nasopharyngeal carcinoma after intensity-modulated radiotherapy

Background: The prognostic values of staging parameters require continual re?assessment amid changes in diag?nostic and therapeutic methods. This study aimed to identify the prognostic factors and failure patterns of non?meta?static nasopharyngeal carcinoma(NPC) in the intensity?modulated radiotherapy(IMRT) era.Methods: We reviewed the data from 749 patients with newly diagnosed, biopsy?proven, non?metastatic NPC in our cancer center(South China, an NPC endemic area) between January 2003 and December 2007. All patients under?went magnetic resonance imaging(MRI) before receiving IMRT. The actuarial survival rates were estimated using the Kaplan–Meier method, and survival curves were compared using the log?rank test. Multivariate analyses with the Cox proportional hazards model were used to test for the independent prognostic factors by backward eliminating insigniicant explanatory variables.Results: The 5?year occurrence rates of local failure, regional failure, locoregional failure, and distant failure were 5.4, 3.0, 7.4, and 17.4%, respectively. The 5?year survival rates were as follows: local relapse?free survival, 94.6%; nodal relapse?free survival, 97.0%; distant metastasis?free survival, 82.6%; disease?free survival, 75.1%; and overall survival, 82.0%. Multivariate Cox regression analysis revealed that orbit involvement was the only signiicant prognostic fac?tor for local failure(P = 0.011). Parapharyngeal tumor extension, retropharyngeal lymph node involvement, and the laterality, longest diameter, and Ho's location of the cervical lymph nodes were signiicant prognostic factors for both distant failure and disease failure(all P < 0.05). Intracranial extension had signiicant prognostic value for distant failure(P = 0.040).Conclusions: The key failure pattern for NPC was distant metastasis in the IMRT era. With changes in diagnostic and therapeutic technologies as well as treatment modalities, the signiicant prognostic parameters for local control have also been altered substantially.

Prognostic value of plasma Epstein-Barr virus DNA level during posttreatment follow-up in the patients with nasopharyngeal carcinoma having undergone intensity-modulated radiotherapy

Background: The value of Epstein-Barr virus(EBV) DNA assay during posttreatment follow-up of the patients with nasopharyngeal carcinoma(NPC) presenting with different pretreatment plasma EBV DNA levels remains unclear. In the present study, we aimed to evaluate the prognostic value of plasma EBV DNA assay during posttreatment followup in the patients with NPC who have undergone intensity-modulated radiotherapy.Methods: The medical records of 385 NPC patients treated with intensity-modulated radiotherapy between November 2009 and February 2012 were reviewed. All patients underwent plasma EBV DNA assays before treatment, within3 months after treatment, and then every 3-12 months during posttreatment follow-up period. The recurrence rates for patients with different pretreatment and posttreatment follow-up plasma EBV DNA levels were analyzed.Results: Of the 385 patients, 267(69.4%) had detectable pretreatment plasma EBV DNA(> 0 copy/mL) and 93(24.2%) had detectable posttreatment EBV DNA during a median follow-up of 52.8 months(range 9.3-73.8 months).Detectable EBV DNA during posttreatment follow-up was found in 14.4%(17/118) and 28.5%(76/267) of patients with undetectable and detectable pretreatment EBV DNA, respectively, and was significantly associated with tumor recurrence in both patient groups. EBV DNA was detectable in 12.8%(40/313) of patients who remained disease-free,56.4%(22/39) of patients with locoregional recurrence alone, and 93.9%(31/33) of patients with distant metastasis as the first recurrence event(P < 0.001); 6.5%(19/292) of patients with undetectable EBV DNA and 57.0%(53/93) of patient with detectable EBV DNA during posttreatment follow-up experienced tumor recurrence. Compared with other cut-off values, the cut-off value of 0 copy/mL for EBV DNA during posttreatment follow-up had the highest area under the ROC curve(AUC) value(0.804,95% confidence interval 0.741-0.868) for predicting tumor recurrence(sensitivity, specificity, and accuracy: 73.6%, 87.2%, and 84.7%, respectively).Conclusion: Plasma EBV DNA level during posttreatment follow-up is a good marker for predicting distant metastasis but not locoregional recurrence in the patients with NPC irrespective of the pretreatment EBV DNA levels.

Plasma Epstein-Barr virus DNA as a biomarker for nasopharyngeal carcinoma

Nasopharyngeal carcinoma(NPC)is common in southern China and Southeast Asia.Epstein-Barr virus(EBV)infection is an important etiology for NPC,and EBV genome can be detected in almost all tumor tissues of NPC in this region.Plasma EBV DNA,when quantitatively analyzed using real-time polymerase chain reaction(PCR),has been developed as a biomarker for NPC.In this review,the different clinical applications of plasma EBV DNA in the management of NPC,including screening,monitoring,and prognostication,are discussed.In addition,the biological issues of circulating EBV DNA,including the molecular nature and clearance kinetics,are also explored.

Effect of heparin on apoptosis in human nasopharyngeal carcinoma CNE2 cells

In order to study the mechanism of the effect of heparin on apoptosis in carcinoma cells, the nasopharyngeal carcinoma cell line CNE2 was used to identify the effect of heparin on apoptosis associated with the expression of c-myc, bax, bcl-2 proteins by use of Hoechst 33258 staining, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL), agarose gel electrophoresis, and flow cytometry, as well as Western blot analysis. The results showed that heparin induced apoptosis of CNE2 cells including the morphologic changes such as reduction in the volume, and the nuclear chromatin condensation, as well as the 'ladder pattern' revealed by agarose gel electrophoresis of DNA in a concentration-dependent manner. The number of TUNEL-positive cells was dramatically increased to 33.6+/-1.2% from 2.8+/-0.3% by treatment with heparin in different concentrations (10 to approximately 40 kU/L). The apoptotic index was increased to 32.5% from 3.5% by detecting SubG1 peaks on flow cytometry. Western blot analysis showed that levels of bcl-2, bax and c-myc were significantly overexpressed by treatment with the increase of heparin concentrations. These results suggest that heparin induces apoptosis of CNE2 cells, which may be regulated by differential expression of apoptosis-related genes.

Detailed Deletion Mapping of Chromosome 9p21-22 in Nasopharyngeal Carcinoma

Objective: To further refine the extent of deletion on chromosome 9p21-22 in nasopharyngeal carcinoma (NPC) and provide evidence for discovering new tumor suppressor gene. Methods: Loss of heterozygosity (LOH) on chromosome 9p21-22 was analyzed in 25 paired blood and tumor samples by using 11 high-density microsatellite polymorphic markers. Results: 17 of 25 cases (68.0%) showed LOH at one or more loci. Higher frequencies of LOH were found at four loci: D9S161 (35.0%), D9S1678 (31.5%), D9S263 (33.3%) and D9S1853 (33.3%), where 6 cases had a contiguous stretch of allelic loss. Conclusion: The minimal common region of deletion might be defined between D9S161 and D9S1853 (estimated about 2.7 cM in extent) at 9p21.1, suggesting that inactivation of one or more tumor suppressor genes located in this region may be an important step in NPC.

THE FINDING OF PATIENTS SUFFERING FROM NASOPHARYNGEAL CARCINOMA (NPC) WHO CONTACTED WITH THE HEXAMETHYLPHOSPHORAMIDE (HMPA)FOR A LONG TERM

In 1975, it was found that the HMPA could induce the nasal tumors in the rats, the carcinogenicity and the Iatency were dose correlated with the HMPA concentration. it was estimated by the National Institute for occupation Safety Health that about 5,000 People were occupationally exposed to HMPA in 1975, and more than 90% exposures are in research laboralories. Since then,no one patient suffering from NPC or nasal tumors has been found. In 1987, in a mass survey of Antibodies to Epstein-Barr Virus specific DNase (EDAb). Authors found that there were eight persons who had a long term contact with HMPA (8-10 years) in 1970-1980 in Guangrhou Chemical Engineering Institute. 2 of the 8 were EDAb positive (high titre) but the nasopharyngeal cavity were not found any abnormal. Owing to the history of contact with HMPA and a vigorous elevation of EDAb titre in the duration of 2.5 yeas' follow up was observed. There 2 persons were considered as a high risk population of NPC and a 'Blind Biopsy' of nasopharynx was suggested. A diagnosis of poorly differentiated squamous carcinoma confirmed pathologically.of these 2 Patients were stage 1(TINOMO) and were treated with radiotherapy and live very well till now. The results suggested that the HMPA might induced human nasopharyngeal carcinoma.

Indication of lower neck irradiation in nasopharyngeal carcinoma without nodal metastasis： the potential impact of tumor volume

Background Elective radiation of lower neck is controversial for nasopharyngeal carcinoma （NPC） without lymph node metastasis （NO disease）. Tumor volume is an important prognostic indicator. The objective of this study is to explore the potential impact of tumor volume on the indication of the lower neck irradiation for N0-NPC, by a qualitative evaluation of the relationship between tumor volume and nodal metastasis. Methods Magnetic resonance （MR） images of 99 consecutive patients with NPC who underwent treatment were retrospectively reviewed. Primary tumor volumes of NPC were semi-automatically measured, nodal metastases were N-classified and neck level involvements were examined. Distributions of tumor volumes among N-category-based groups and distributions of N-categories among tumor volume-based groups were analyzed, respectively. Results The numbers of patients with NO to N3 disease were 12, 39, 32, and 16, respectively. The volumes of primary tumor were from 3.3 to 89.6 ml, with a median of 17.1 ml. For patients with nodal metastasis, tumor volume did not increase significantly with the advancing of N-category （P 〉0.05）. No significant difference was found for the distribution of N1, N2, and N3 categories among tumor volume-based groups （P 〉0.05）. Nevertheless patients with nodal metastasis had significantly larger tumor volumes than those without metastasis （P 〈0.05）. Patients with larger tumor volumes were associated with an increased incidence of nodal metastasis. Conclusions Certain positive correlations existed between tumor volume and the presence of nodal metastasis. The tumor volume （〉10 ml） is a potential indicator for the lower neck irradiation for N0-NPC.

The emergence of tumor-infiltrating lymphocytes in nasopharyngeal carcinoma:Predictive value and immunotherapy implications

The clinical study of nasopharyngeal carcinoma(NPC)often reveals a large number of lymphocytes infiltrating the primary tumor site.As an important part of the tumor microenvironment,tumor-infiltrating lymphocytes(TILs)do not exist alone but as a complex multicellular population with high heterogeneity.TILs play an extremely significant role in the occurrence,development,invasion and metastasis of NPC.The latest research shows that they participate in tumorigenesis and treatment,and the composition,quantity,functional status and distribution of TILs subsets have good predictive value for the prognosis of NPC patients.TILs are an independent prognostic factor for TNM stage and significantly correlated with better prognosis.Additionally,adoptive immunotherapy using anti-tumor TILs has achieved good results in a variety of solid tumors including NPC.This review evaluates recent clinical and preclinical studies of NPC,summarizes the role of TILs in promoting and inhibiting tumor growth,evaluates the predictive value of TILs,and explores the potential benefits of TILs-based immunotherapy in the treatment of NPC.

Clinical utility of Epstein-Barr virus DNA and other liquid biopsy markers in nasopharyngeal carcinoma

Nasopharyngeal carcinoma(NPC)is a malignant epithelial tumor ubiquitously associated with the Epstein-Barr virus(EBV),which is highly prevalent in South China,Southeast Asia,and North Africa.Despite being a highly radio-sensitive and treatable cancer,a majority of NPC patients are diagnosed in their advanced stage,and locoregional and distant relapses following definitive treatment contribute largely to cancer-specific mortality among these patients.Given that EBV-driven NPC is the predominant variant seen in endemic regions,various EBV detection methods have been developed and are utilized in screening,prognostication,and post-treatment surveillance of NPC patients.While the Immunoglobulin A(IgA)serology assay is the most extensively studied EBV detection method,the detection of plasma EBV DNA released during replication or cellular apoptosis has shown superior outcomes in endemic population screening,prognostication,and detection of distant relapse.Furthermore,there is emerging evidence on the use of circulating tumor cells,microRNAs,DNA hypermethylation,and combination assays in various clinical scenarios.Herein,this paper provides a comprehensive overview of the relevant studies using various EBV detection techniques in the management of NPC.Specifically,the recent advances,clinical evidence,and challenges associated with the clinical application of EBV liquid biopsies in population screening,prognostication,and surveillance of NPC are presented.

A cDNA located on chromosome 7q32 shows loss of expression in epithelial cell line of nasopharyngeal carcinoma

To isolate and clone the tumor suppressor gene on chromosomal region 7q32 correlated with the carcinogenesis of human nasopharyngeal carcinoma (NPC) Methods The genotypes of polymorphic microsatellite markers on 7q32 in DNA from 24 biopsies of nasopharyngeal carcinoma and matched normal blood cells were identified The expression levels of 20 expressed sequence tags (ESTs) on 7q32 between human nasopharyngeal carcinoma epithelial 1 (HNE 1) and primary cultures of normal nasopharyngeal epithelial (PNNE) cells were compared using differential RT PCR and Northern hybridization The quantity of AA070437 DNA and mRNA was detected by differential PCR and differential RT PCR, respectively Results Loss of heterozygosity (LOH) was found in 25%-46% of NPC biopsies AA070437 EST expression was down regulated in HNE 1 cell compared to PNNE cells The down regulation of AA070437 was found in 30 7% of NPC biopsies and allelic loss of AA070437 was observed in 29 1% of NPC biopsies Conclusion Our results show that AA070437 EST is negatively related with the occurrence of human NPC and may represent a candidate tumor suppressor gene of NPC on 7q32

Retreatment in locally recurrent nasopharyngeal carcinoma:Current status and perspectives

1 Background Nasopharyngeal carcinoma(NPC)arises from the epithelial cells that cover and line the nasopharynx.While it is considered a rare cancer globally,it is commonly observed in South China and a few other ethnically distinct racial groups.Due to its propensity to spread early through the submucosal tissue and the highly infiltrative nature of this disease,NPC spreads easily through areas of lesser resistance within the pharyngobasilar fascia with a tendency for neural infiltration[1-3].

The susceptibility gene for familial nasopharyngeal carcinoma is mapped on chromosome 4p11-p14 by haplotype analyses

In our previous study, one candidate suscepti-bility locus for familial nasopharyngeal carcinoma (NPC) has been defined to a 14.21-cM region on 4p15.1-q12, whereas the distal minimum boundary of this region remained to be further determined in respect that the two markers D4S2996 and D4S428 were uninformative. In the present study, we carried out a haplotype analysis to identify the exact bound-ary by using the combination of a set of microsatellite mark-ers and single nucleotide polymorphism (SNP) markers in two major NPC families. We defined the exact distal bound-ary between D4S1577 and D4S3347, and consequently shortened the susceptibility locus to an 8.29-cM segment on 4p11-p14.

Efficacy of the hypoxia-activated prodrug evofosfamide (TH-302) in nasopharyngeal carcinoma in vitro and in vivo

Background:Tumor hypoxia is considered an important factor in metastasis and disease relapse.Evofosfamide is a hypoxia-activated prodrug that selectively targets the hypoxic regions of solid tumors.As hypoxia-inducible factor-1α(HIF-1α)is overexpressed in nasopharyngeal carcinoma(NPC)tissues,we performed the present study to evaluate the efficacy profile of evofosfamide in NPC.Methods:We evaluated the efficacy of evofosfamide as a single agent or combined with cisplatin(DDP)in the NPC cell lines CNE-2,HONE-1 and HNE-1,and in nude mouse xenograft tumor models.Results:Evofosfamide exhibited hypoxia-selective cytotoxicity in NPC cell lines,with 50%inhibition concentration(IC50)values of 8.33±0.75,7.62±0.67,and 0.31±0.07μmol/L under hypoxia in CNE-2,HONE-1 and HNE-1 cells,respectively.The sensitization ranged from ninefold to greater than 300-fold under hypoxia compared with normoxia controls.The combination of evofosfamide with DDP had a synergistic effect on cytotoxicity in the NPC cell lines by combination index values assessment.Cell cycle G2 phase was arrested after treated with 0.05μmol/L evofosfamide under hypoxia.Histone H2AX phosphorylation(γH2AX)(a marker of DNA damage)expression increased while HIF-1αexpression suppressed after evofosfamide treatment under hypoxic conditions.In the HNE-1 NPC xenograft models,evofosfamide exhibited antitumor activity both as a single agent and combined with DDP.Hypoxic regions in xeno-graft tissue were reduced after both evofosfamide monotherapy and combined therapy with DDP.Conclusions:Our results present preclinical evidence for targeting the selective hypoxic portion of NPC by evofosfa-mide as a single agent and combined with DDP and provide rationale for the potential clinical application of evofosfa-mide for the treatment of nasopharyngeal carcinoma.