Non-B, Non-C Hepatocellular Carcinoma in an HBV- and HCV-Endemic Area: A Community-Based Prospective Longitudinal Study.

A large community cohort of adults who participated in a health screening program from 2003 to 2013 were prospectively analyzed for the risk factors of non-B, non-C (NBNC) hepatocellular carcinoma (HCC). The serostatus of hepatitis B and C of 52,642 participants was linked to the mortality and cancer registration data of the Health and Welfare Data Science Center, Ministry of Health and Welfare, Taiwan. During a median follow-up of 6 years, 35 of the 43,545 participants who were negative for both HBsAg and anti-HCV antibody developed HCC. Multivariate Cox regression analysis revealed that old age (hazard ratio, 95% CI: 1.058, 1.019−1.098, p = 0.003); male sex (2.446, 1.200−4.985, p = 0.014); high aspartate aminotransferase levels (6.816, 2.945−15.779, p < 0.001); fibrosis index based on four factor score (1.262, 1.154−1.381, p < 0.001); blood sugar (1.009, 1.002−1.015, p = 0.006); and alpha-fetoprotein ≥15 ng/mL (143.938, 43.094−480.760, p < 0.001) were independent risk factors for HCC. By contrast, triglyceride >150 mg/dL was associated with a decreased risk of HCC (0.216, 0.074−0.625, p = 0.005). This prospective community-based study provided insights into the potential HCC risk factors which may shed some light in HCC prevention and screening.

A novel HIF1α-STIL-FOXM1 axis regulates tumor metastasis.

BACKGROUND: Metastasis is the major cause of morbidity and mortality in cancer that involves in multiple steps including epithelial-mesenchymal transition (EMT) process. Centrosome is an organelle that functions as the major microtubule organizing center (MTOC), and centrosome abnormalities are commonly correlated with tumor aggressiveness. However, the conclusive mechanisms indicating specific centrosomal proteins participated in tumor progression and metastasis remain largely unknown. METHODS: The expression levels of centriolar/centrosomal genes in various types of cancers were first examined by in silico analysis of the data derived from The Cancer Genome Atlas (TCGA), Gene Expression Omnibus (GEO), and European Bioinformatics Institute (EBI) datasets. The expression of STIL (SCL/TAL1-interrupting locus) protein in clinical specimens was further assessed by Immunohistochemistry (IHC) analysis and the oncogenic roles of STIL in tumorigenesis were analyzed using in vitro and in vivo assays, including cell migration, invasion, xenograft tumor formation, and metastasis assays. The transcriptome differences between low- and high-STIL expression cells were analyzed by RNA-seq to uncover candidate genes involved in oncogenic pathways. The quantitative polymerase chain reaction (qPCR) and reporter assays were performed to confirm the results. The chromatin immunoprecipitation (ChIP)-qPCR assay was applied to demonstrate the binding of transcriptional factors to the promoter. RESULTS: The expression of STIL shows the most significant increase in lung and various other types of cancers, and is highly associated with patients' survival rate. Depletion of STIL inhibits tumor growth and metastasis. Interestingly, excess STIL activates the EMT pathway, and subsequently enhances cancer cell migration and invasion. Importantly, we reveal an unexpected role of STIL in tumor metastasis. A subset of STIL translocate into nucleus and associate with FOXM1 (Forkhead box protein M1) to promote tumor metastasis and stemness via FOXM1-mediated downstream target genes. Furthermore, we demonstrate that hypoxia-inducible factor 1α (HIF1α) directly binds to the STIL promoter and upregulates STIL expression under hypoxic condition. CONCLUSIONS: Our findings indicate that STIL promotes tumor metastasis through the HIF1α-STIL-FOXM1 axis, and highlight the importance of STIL as a promising therapeutic target for lung cancer treatment.

The C-degron pathway eliminates mislocalized proteins and products of deubiquitinating enzymes.

Protein termini are determinants of protein stability. Proteins bearing degradation signals, or degrons, at their amino- or carboxyl-termini are eliminated by the N- or C-degron pathways, respectively. We aimed to elucidate the function of C-degron pathways and to unveil how normal proteomes are exempt from C-degron pathway-mediated destruction. Our data reveal that C-degron pathways remove mislocalized cellular proteins and cleavage products of deubiquitinating enzymes. Furthermore, the C-degron and N-degron pathways cooperate in protein removal. Proteome analysis revealed a shortfall in normal proteins targeted by C-degron pathways, but not of defective proteins, suggesting proteolysis-based immunity as a constraint for protein evolution/selection. Our work highlights the importance of protein termini for protein quality surveillance, and the relationship between the functional proteome and protein degradation pathways.

Music, heart rate variability, and symptom clusters: a comparative study.

PURPOSE: This study aimed to explore the possible range of change of a single-session music intervention (SMI) on symptom clusters and neurological reactivity for women with breast cancer undergoing chemotherapy. METHODS: A parallel and randomized, controlled study with repeated measures design was used. A total of 100 women with breast cancer were randomly assigned to the SMI or a control group. The outcome measurements of symptom cluster were collected using the Multidimensional Fatigue Symptom Inventory, Pittsburgh Sleep Quality Index, the Hospital Anxiety and Depression Scale, and the neurological reactivity with heart rate variability at four time points: before commencement of the intervention (T0), immediately afterward (T1), 1 week later (T2), and 3 weeks after the intervention (T3). RESULTS: Of the 50 women in each group, 46 in the SMI and 48 in the control group completed the post-test at T3. Multivariate analysis of variance indicated that the SMI group had a medium effect in change of symptom clusters compared to the control group at T2. Moreover, after adjusting for baseline between normal and higher levels of sympathetic tone activity, significant differences existed in fatigue and depression at T2 and sleep disturbance at T3. CONCLUSIONS: A single-session music intervention can be effectively used to reduce symptom clusters for women with breast cancer. Targeting those who have a higher level of sympathetic tone activity is recommended.

Did AFP-L3 save ultrasonography in community screening?

In the community screening, those subjects with elevated serum alpha-fetoprotein (AFP) required further abdomen ultrasonography (US) to detect hepatocellular carcinoma (HCC). However, some chronic hepatitis patients might have elevated AFP. AFP-L3, has been proposed to differentiate HCC and hepatitis in elevated AFP cases in Japan for decades, but the utility is limited outside Japan. We conducted this study to elucidate the role of AFP-L3 in the community and the possibility of saving unnecessary US. A total of 56,702 subjects underwent a large-scale healthcare screening in Tainan county in 2004. Among them, 286 residents with AFP more than 20 ng/ml further received US and 169 (59%) had stored baseline sera were enrolled into this study in 2013. Their AFP and AFP-L3 levels were further detected. HCC patients were initially identified through US and personal history. Among 169 studied sera, only 148 (87.6%) samples still had AFP level more than 20 ng/ml after a 10-years frozen period. The decrease of AFP level was significant (481.3 ± 2093.8 ng/ml and 456.1 ± 2095.3 ng/ml in paired-T test, p < 0.001). Focusing on these 148 cases, 23 (15.5%) HCC cases were diagnosed at the baseline screening. There was no difference of AFP-L3 level between HCC and non-HCC cases. Using AFP-L3 to predict HCC, the area under Receiver Operating Characteristic curve was as low as 52%, p = 0.757. Too long frozen period might lower the quality of stored sera. Additionally, AFP-L3 might not provide more information for HCC identification to save advanced US examinations in the community screening.

Comparison of group vs self-directed music interventions to reduce chemotherapy-related distress and cognitive appraisal: an exploratory study.

PURPOSE: The purpose of this study was to determine effects of group music intervention and self-directed music intervention on anxiety, depression, and cognitive appraisal among women with breast cancer. METHODS: A quasi-experimental design randomly assigned 60 women undergoing chemotherapy to 3 groups: group music intervention, self-directed music intervention, or a control group. The Hospital Anxiety and Depression Scale and the Mini-Mental Adjustment to Cancer Scale were administered before, after the 8-week interventions, and at 3-month follow-up. RESULTS: Of the 52 women completing the study, results indicated that group music intervention had a significant (p < .01) immediate effect to decrease helplessness/hopelessness and anxious preoccupation and significant effects for reducing anxiety, depression, helplessness/hopelessness, and cognitive avoidance compared to the other two groups at 3-month follow-up. CONCLUSIONS: Group music intervention can be considered an effective supportive care in alleviating the chemotherapy-related distress and enhancing cognition modification of women with breast cancer. Further research is needed to determine the role of cognitive appraisal in the illness trajectory.

Dynamic association rules for gene expression data analysis.

BACKGROUND: The purpose of gene expression analysis is to look for the association between regulation of gene expression levels and phenotypic variations. This association based on gene expression profile has been used to determine whether the induction/repression of genes correspond to phenotypic variations including cell regulations, clinical diagnoses and drug development. Statistical analyses on microarray data have been developed to resolve gene selection issue. However, these methods do not inform us of causality between genes and phenotypes. In this paper, we propose the dynamic association rule algorithm (DAR algorithm) which helps ones to efficiently select a subset of significant genes for subsequent analysis. The DAR algorithm is based on association rules from market basket analysis in marketing. We first propose a statistical way, based on constructing a one-sided confidence interval and hypothesis testing, to determine if an association rule is meaningful. Based on the proposed statistical method, we then developed the DAR algorithm for gene expression data analysis. The method was applied to analyze four microarray datasets and one Next Generation Sequencing (NGS) dataset: the Mice Apo A1 dataset, the whole genome expression dataset of mouse embryonic stem cells, expression profiling of the bone marrow of Leukemia patients, Microarray Quality Control (MAQC) data set and the RNA-seq dataset of a mouse genomic imprinting study. A comparison of the proposed method with the t-test on the expression profiling of the bone marrow of Leukemia patients was conducted. RESULTS: We developed a statistical way, based on the concept of confidence interval, to determine the minimum support and minimum confidence for mining association relationships among items. With the minimum support and minimum confidence, one can find significant rules in one single step. The DAR algorithm was then developed for gene expression data analysis. Four gene expression datasets showed that the proposed DAR algorithm not only was able to identify a set of differentially expressed genes that largely agreed with that of other methods, but also provided an efficient and accurate way to find influential genes of a disease. CONCLUSIONS: In the paper, the well-established association rule mining technique from marketing has been successfully modified to determine the minimum support and minimum confidence based on the concept of confidence interval and hypothesis testing. It can be applied to gene expression data to mine significant association rules between gene regulation and phenotype. The proposed DAR algorithm provides an efficient way to find influential genes that underlie the phenotypic variance.

Comparison Stratagems of Post-Screening Management of Anti-HCV-Positive Community Residents: Simple Notification, Active Referral, or Accessible Medical Care.

To elucidate the results of post-screening care stratagems for anti-hepatitis C virus (HCV)-positive subjects in the community. Part I methods: The intervention program: A total of 151,790 subjects underwent a large-scale healthcare screening. Subjects aged less than 65 years, with anti-HCV-positive and alanine aminotransferase (ALT) level more than 80 IU/L were followed-up to answer a structured questionnaire. Those responders who met the reimbursement criteria of Taiwan's National Health Insurance for anti-HCV treatment were referred for treatment. Part II: The accessible medical care program: In Yujing township, 271 HCV residents who have been screened before were invited to a bi-weekly hepatitis clinic in Yujing health center. Part-I results: A total of 907 anti-HCV-positive subjects responded and 197(21.7%) were advised the treatment, but only 83(9.2%) did. Finally, 47 patients achieved a sustained virological response (SVR). After this intervention program, 96(10.6%) additional patients were encouraged to be referred, 33(3.6%) received treatment and 20 obtained a SVR. Part II: A total of 140(51.7%) subjects responded and 112 were anti-HCV-positive including 31(27.7%) HCV RNA-negative, 49(43.8%) HCV RNA-positive plus ALT less than 40 IU/L and 32(28.5%) HCV RNA-positive plus ALT more than 40 IU/L. During the follow-up, 14 of 49 patients had ALT more than 40 IU/L. Among 46 eligible HCV patients, 15(32.6%) received treatment and 10 achieved a SVR. Simple notification only made 9.2% of the screened HCV patients treat. Active referral could encourage additional 3.6% to be treated. Additionally, accessible medical care program could result in treatment of 32.6% elderly eligible patients.

[Nursing care for a lung cancer patient with brain metastasis using the family resiliency model].

This article describes the experience of the author in providing nursing care to a lung cancer patient with brain metastasis who was unable to care for herself. The period of care ran from July 26th to August 7th, 2012. The focus of the article is on the problems of disease adaptation and the coping strategies of the patient and her primary caregivers. The author used the Family Resiliency Model to collect information via physical examination, observation, and interviews. Five major nursing problems were identified in this case: risk of aspiration, self-care deficits, adjustment disorder, caregiver role strain, and family coping ineffectiveness. Based on these problems, the author constructed an individualized care plan to: 1) improve the self-care ability of the patient, 2) enhance the skills of the primary caregiver, 3) recruit the timely assistance of other family members, 4) and reduce the burden of the primary caregiver. The primary goal of this care plan was to promote the quality of life of the patient and her family.

Diabetes mellitus, metabolic syndrome and obesity are not significant risk factors for hepatocellular carcinoma in an HBV- and HCV-endemic area of Southern Taiwan.

A prominent factor in hepatocellular carcinoma (HCC) is chronic infection with hepatitis B virus (HBV) and hepatitis C virus (HCV). Diabetes mellitus (DM), metabolic syndrome (MetS), and obesity have also been implicated in HCC development, but these associations are not observed in all HBV- and HCV-endemic areas. We attempted to clarify the role of these factors in HCC development in an HBV- and HCV-endemic area in southern Taiwan. A community-based health examination was conducted in 2004 in Tainan County. After individuals with incomplete data and those with known HCC were excluded, there were 56,231 participants who were over 40 years of age. A further 262 HCC cases were identified from the National Cancer Registration Database records from 2005 to 2007. The hepatitis B surface antigen (HBsAg) seropositivity, anti-HCV seropositivity, platelet count, serum biochemical data, blood pressure, sociodemographic information, and anthropometric measurements were analyzed. Survival analyses were used to identify the associations between these factors and HCC. For the 262 HCC cases, male gender and age greater than 65 years were risk factors. Furthermore, a high alanine aminotransferase level, chronic HBV and/or HCV infection, and liver cirrhosis were also risk factors for HCC. However, DM, MetS and obesity were not associated with HCC development in the non-HBV-/non-HCV-infected, HBV, HCV, or dual B/C groups. In this HBV- and HCV- endemic area, DM, MetS and obesity were not risk factors for developing HCC.

Overexpressed-eIF3I interacted and activated oncogenic Akt1 is a theranostic target in human hepatocellular carcinoma.

UNLABELLED: Eukaryotic translation initiation factor 3 subunit I (eIF3I) with transforming capability is often overexpressed in human hepatocellular carcinoma (HCC) but its oncogenic mechanisms remain unknown. We demonstrate that eIF3I is overexpressed in various cancers along with activated Akt1 phosphorylation and kinase activity in an eIF3I dose-dependent manner. A novel eIF3I and Akt1 protein interaction was identified in HCC cell lines and tissues and was required for eIF3I-mediated activation of Akt1 signaling. Expression of either antisense eIF3I or dominant negative Akt1 mutant suppressed eIF3I-mediated Akt1 oncogenic signaling and various other tumorigenic effects. Oncogenic domain mapping of the eIF3I and Akt1 interaction suggested that the C-terminal eIF3I interacted with the Akt1 kinase domain and conferred the majority of oncogenic functions. In addition, eIF3I interaction with Akt1 prevented PP2A dephosphorylation of Akt1 and resulted in constitutively active Akt1 oncogenic signaling. Importantly, concordant expression of endogenous eIF3I and phospho-Akt1 was detected in HCC cell lines and tissues. Treatment of eIF3I overexpressing HCC cells with the Akt1 specific inhibitor API-2 suppressed eIF3I-mediated tumorigenesis in vitro and in vivo. CONCLUSION: We describe a constitutive Akt1 oncogenic mechanism resulting from interaction of overexpressed eIF3I with Akt1 that prevents PP2A-mediated dephosphorylation. Overexpression of eIF3I in HCC is oncogenic and is a surrogate marker and therapeutic target for treatment with Akt1 inhibitors.

Hepatocellular carcinoma surveillance at 4- vs. 12-month intervals for patients with chronic viral hepatitis: a randomized study in community.

OBJECTIVES: To compare the efficacy of hepatocellular carcinoma (HCC) surveillance at 4- and 12-month intervals in a community for patients with chronic viral hepatitis and thrombocytopenia. METHODS: In 10 townships, adults (≥ 40 years) with platelet ≤ 150 (× 10(9))/l, positive hepatitis B surface antigen, or antibody to hepatitis C virus were invited to this study. These townships were randomized into 4- (group A) and 12-month (group B) interval surveillance groups. Seven hundred and eighty-five and 796 residents met the study criteria in groups A and B. Ultrasonography (US) was the surveillance method. RESULTS: A total of 744 residents (group A: 387; group B: 357) were enrolled. In the study period, HCC was diagnosed in 39 residents (group A: 24; group B: 15). There was no difference in cumulative 3-year HCC incidence between the two groups. The tumors were smaller in group A than in group B, though group A had more patients with tumor ≤ 2 cm (P = 0.003) who were in Barcelona Clinic Liver Cancer (BCLC) very-early stage (P = 0.017) and had undergone curative treatments (P = 0.049). Male gender, cirrhosis, and platelet ≤ 100 (× 10(9))/l were associated factors of HCC occurrence. There was no difference in 4-year overall survival between the two groups. Patients undergoing recommended treatments had better 4-year survival rates. CONCLUSIONS: Compared with 12-month interval, US surveillance at 4-month interval detected more patients with HCC ≤ 2 cm who were in BCLC very-early stage and were fit for curative treatments. Up to 4-year follow-up, however, the overall survival was not different.

Sumoylation-promoted enterovirus 71 3C degradation correlates with a reduction in viral replication and cell apoptosis.

Enterovirus 71 (EV71), a member of the Picornaviridae family, may cause serious clinical manifestations associated with the central nervous system. Enterovirus 3C protease is required for virus replication and can trigger host cell apoptosis via cleaving viral polyprotein precursor and cellular proteins, respectively. Although the role of the 3C protease in processing viral and cellular proteins has been established, very little is known about the modulation of EV71 3C function by host cellular factors. Here, we show that sumoylation promotes EV71 3C protein ubiquitination for degradation, correlating with a decrease of EV71 in virus replication and cell apoptosis. SUMO E2-conjugating enzyme Ubc9 was identified as an EV71 3C-interacting protein. Further studies revealed that EV71 3C can be SUMO (small ubiquitin-like modifier)-modified at residue Lys-52. Sumoylation down-regulated 3C protease activity in vitro and also 3C protein stability in cells, in agreement with data suggesting 3C K52R protein induced greater substrate cleavage and apoptosis in cells. More importantly, the recombinant EV71 3C K52R virus infection conferred more apoptotic phenotype and increased virus levels in culture cells, which also correlated with a mouse model showing increased levels of viral VP1 protein in intestine and neuron loss in the spinal cord with EV71 3C K52R recombinant viral infection. Finally, we show that EV71 3C amino acid residues 45-52 involved in Ubc9 interaction determined the extent of 3C sumoylation and protein stability. Our results uncover a previously undescribed cellular regulatory event against EV71 virus replication and host cell apoptosis by sumoylation at 3C protease.

Anaemia following initiation of androgen deprivation therapy for metastatic prostate cancer: a retrospective chart review.

OBJECTIVE: Haemoglobin levels often decline into the anaemic range with androgen deprivation therapy (ADT). We conducted a chart review of patients receiving ADT for metastatic prostate cancer to assess anaemia-related symptoms. METHODS: 135 stage IV prostate cancer cases were reviewed for treatment type; haemoglobin values before and after treatment; and symptoms of anaemia. Mean haemoglobin levels before and after for all treatment forms, for leuprolide alone, and for combination leuprolide/bicalutamide were calculated and evaluated for significant differences. The numbers of patients developing symptoms were recorded and the effects of specific therapies evaluated. RESULTS: For all ADT treated patients, mean haemoglobin declined by -1.11 g/dL (p<.0001). Leuprolide-alone treated patients had a mean decline of -1.66 g/dL (p<0.0001). Leuprolide and bicalutamide combination treatment caused a mean decline of -0.78 g/dL (p=0.0426). 16 of 43 patients had anemia symptoms. Contingency analysis with Fisher's exact test shows patients receiving leuprolide therapy alone versus other forms of ADT were significantly less likely to have symptoms (chi(2)=0.0190). CONCLUSIONS: The present study confirms that ADT results in a significant drop in haemoglobin levels into the anaemic range. A number of patients become symptomatic from this change. Practitioners should monitor haemoglobin levels, and treat symptomatic patients.

CD13 (aminopeptidase N) can associate with tumor-associated antigen L6 and enhance the motility of human lung cancer cells.

Cancer metastasis is a multiple-step process that involves the regulated interaction of diverse cellular proteins. We recently reported that the expression of tumor-associated antigen L6 (TAL6) promoted the invasiveness of lung cancer cells and was inversely correlated with disease-free survival of squamous lung carcinoma patients. We now report that CD13 (aminopeptidase N) can associate with TAL6 and can enhance cancer cell migration. CD13 was shown by coimmunoprecipitation to associate in vitro with TAL6 on several cancer cell lines and to associate in vivo by antibody-mediated copatching immunofluorescence. CD13 was selectively expressed on highly invasive CL1-5 lung cancer cells as compared to poorly invasive CL1-0 lung cancer cells. The role of CD13 aminopeptidase activity in regulating cell motility was investigated with chemical inhibitors, specific antibodies and a catalytically inactive CD13 protein. Inhibition of CD13 aminopeptidase activity by nontoxic concentrations of leuhistin modestly decreased the migration of CL1-5 cells. In contrast, binding of CD13 by specific antibodies significantly reduced both the migration and the invasion of CL1-5 cells. Poorly invasive CL1-0 cells that stably expressed CD13 displayed significantly (p < or = 0.0005) enhanced cell migration (300% of control). Expression of an enzymatically inactive CD13 mutant on CL1-0 cells also significantly (p < or = 0.0005) enhanced cell migration (200% of control). Our results show that TAL6 and CD13 can form a complex on lung cancer cells, that these molecules can modulate cell migration and invasion and that the influence of CD13 on cell motility did not strictly depend on its aminopeptidase activity.

Epstein-Barr virus latent membrane protein 1 represses p53-mediated DNA repair and transcriptional activity.

The latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV), a viral oncogene, is essential for transformation of resting B cells by the virus. We previously demonstrated that LMP1 could repress DNA repair in p53-wild-type and p53-deficient human epithelial cells. In this study, using a host cell reactivation (HCR) assay, we demonstrated that p53-enhanced DNA repair was repressed by LMP1 in p53-deficient cells. Moreover, we found that LMP1 was able to repress p53-dependent transcriptional activity. Regarding the mechanisms of p53 repression by LMP1, we found that LMP1 did not inhibit p53 function through direct interaction, by promoting protein degradation or reducing its DNA-binding ability. Using chimeric proteins in the reporter assay, we demonstrated that LMP1 inhibited p53 transactivation by influencing the N-terminal transactivation domain of p53. Subsequent experiments using various LMP1 deletion mutants indicated that a C-terminus-activating region of LMP1, CTAR1 or CTAR2, is responsible for the repression of p53-mediated DNA repair and p53-dependent transcription, which is correlated with the region responsible for NF-kappaB activation. Furthermore, blockage of NF-kappaB signalling by IkappaB-DeltaN was shown to abolish the repression of p53 by LMP1, suggesting that LMP1 likely repressed p53 function through the NF-kappaB pathway. Based on these results, we propose that inhibition of p53-dependent transcriptional activity and DNA repair by LMP1 results in the loss of p53 activity for maintaining genomic stability, which may contribute to the oncogenesis of LMP1 in human epithelial cells.

Epstein-Barr virus latent membrane protein 1 induces micronucleus formation, represses DNA repair and enhances sensitivity to DNA-damaging agents in human epithelial cells.

The latent membrane protein 1 (LMP1) of Epstein-Barr virus (EBV) is a viral oncogene and it is essential for the transformation of resting B cells by the virus. The protein acts as a ligand-less membrane receptor and triggers numerous cellular signaling pathways. Cellular transformation frequently has been associated with genomic instability. To investigate whether EBV LMP1 induces chromosomal aberrations, micronucleus (MN) formation was examined in LMP1-expressing epithelial cells. The expression of wild-type LMP1 enhanced both spontaneous and bleomycin-induced MN formation. MN formation may be induced by inactivation of DNA repair and, therefore, we investigated the effect of LMP1 on DNA repair, using a host cell reactivation (HCR) assay. In the HCR assay, LMP1 reduced the capacity for DNA repair of both NPC-TW01 (p53-wild-type) and H1299 (p53-deficient) cells. As reduction of DNA repair by LMP1 occurs in p53-wild-type and p53-deficient cells, it seems that LMP1 can repress DNA repair in a p53-independent manner. Inactivation of DNA repair may render cells sensitive to DNA-damaging agents. In this study, H1299 cells harboring LMP1 were shown to be more sensitive to UV and bleomycin than those with a vector control. Using various deletion mutants of EBV LMP1 to determine the regions of LMP1 required to enhance MN formation, inhibit DNA repair and sensitize cells to DNA-damaging agents, we found that the region a. a. 189-222 (located within the CTAR1 domain) was responsible for sensitizing cells to UV and bleomycin, as well as for enhancing MN formation and repressing DNA repair. Based on these results, we suggest that disruption of DNA repair by LMP-1 results in an accumulation of unrepaired DNA and consequent genomic instability, which may contribute to the oncogenesis of LMP1 in human epithelial cells.