A concealed inguinal presentation of a gastrointestinal stromal tumor (GIST): a case report and literature review.

BACKGROUND: Gastrointestinal stromal tumor (GIST) can arise anyplace along the gastrointestinal (GI) tract. The uncommon tumor location in groin area is rarely reported. CASE PRESENTATION: We herein reported a metastasized case presented as GI hemorrhage complicated with indirect hernia, and underwent tumor cytoreduction, herniorrhaphy and chemotherapy for jejunal GIST. The case was described consecutively based on the process of surgical management, with a good follow-up result. A literature review by searching similar case reports from two national medical databases was performed to summarize clinical features of such unusual presentation of GIST, which included hernia characteristics, short- and long-term outcomes of this disease. It showed GIST presenting as groin hernia was rarely reported and all available 11 cases suggested a primary tumor and required both tumor resection and hernia repair. The long-term results indicated 64.3% overall survival at 5 years after the incidental diagnosis. CONCLUSIONS: Inguinal hernia is an extremely rare presentation of GIST, with limited case reports available in the literature. A radical involving tumor resection plus hernia repair is an optimal surgical approach for such uncommon condition. An adjuvant medication mounting on mutated KIT gene should be strictly followed for high risk cases.

A new prognostic histopathologic classification of nasopharyngeal carcinoma.

BACKGROUND: The current World Health Organization (WHO) classification of nasopharyngeal carcinoma (NPC) conveys little prognostic information. This study aimed to propose an NPC histopathologic classification that can potentially be used to predict prognosis and treatment response. METHODS: We initially developed a histopathologic classification based on the morphologic traits and cell differentiation of tumors of 2716 NPC patients who were identified at Sun Yat-sen University Cancer Center (SYSUCC) (training cohort). Then, the proposed classification was applied to 1702 patients (retrospective validation cohort) from hospitals outside SYSUCC and 1613 patients (prospective validation cohort) from SYSUCC. The efficacy of radiochemotherapy and radiotherapy modalities was compared between the proposed subtypes. We used Cox proportional hazards models to estimate hazard ratios (HRs) with 95% confidence intervals (CI) for overall survival (OS). RESULTS: The 5-year OS rates for all NPC patients who were diagnosed with epithelial carcinoma (EC; 3708 patients), mixed sarcomatoid-epithelial carcinoma (MSEC; 1247 patients), sarcomatoid carcinoma (SC; 823 patients), and squamous cell carcinoma (SCC; 253 patients) were 79.4%, 70.5%, 59.6%, and 42.6%, respectively (P < 0.001). In multivariate models, patients with MSEC had a shorter OS than patients with EC (HR = 1.44, 95% CI = 1.27-1.62), SC (HR = 2.00, 95% CI = 1.76-2.28), or SCC (HR = 4.23, 95% CI = 3.34-5.38). Radiochemotherapy significantly improved survival compared with radiotherapy alone for patients with EC (HR = 0.67, 95% CI = 0.56-0.80), MSEC (HR = 0.58, 95% CI = 0.49-0.75), and possibly for those with SCC (HR = 0.63; 95% CI = 0.40-0.98), but not for patients with SC (HR = 0.97, 95% CI = 0.74-1.28). CONCLUSIONS: The proposed classification offers more information for the prediction of NPC prognosis compared with the WHO classification and might be a valuable tool to guide treatment decisions for subtypes that are associated with a poor prognosis.

Targeting the anaphase-promoting complex/cyclosome (APC/C)- bromodomain containing 7 (BRD7) pathway for human osteosarcoma.

Osteosarcoma is the most common primary malignant bone tumor in childhood and adolescence and has a propensity for local invasion and early lung metastasis. However, the current therapies often result in chemoresistance, and a therapeutic target is not available in the clinic for osteosarcoma. Here, we report that BRD7 forms a complex with the anaphase-promoting complex/cyclosome (APC/C) and is degraded by APC/C(cdh1) and APC/C(cdc20) during the cell cycle. Moreover, BRD7 is a tumor suppressor in osteosarcoma, and the BRD7 mutant resistant to degradation by APC/C is more efficient than the wild-type protein at suppressing proliferation, colony formation, and tumor growth of osteosarcoma in vitro and in vivo. The combination of proTAME, an inhibitor of APC/C, with chemotherapeutic drugs efficiently targets osteosarcoma in vitro. Furthermore, there is a strong inverse correlation of protein levels between BRD7 and Cdh1 or Cdc20, and lower BRD7 expression is an indicator for poor prognosis in patients with osteosarcoma. Collectively, our results indicate that targeting the APC/C-BRD7 pathway may be a novel strategy for treating osteosarcoma.

Glycogen synthase kinase-3ß, NF-κB signaling, and tumorigenesis of human osteosarcoma.

BACKGROUND: Glycogen synthase kinase-3ß (GSK-3ß), a serine/threonine protein kinase, may function as a tumor suppressor or an oncogene, depending on the tumor type. We sought to determine the biological function of GSK-3ß in osteosarcoma, a rare pediatric cancer for which the identification of new therapeutic targets is urgent. METHODS: We used cell viability assays, colony formation assays, and apoptosis assays to analyze the effects of altered GSK-3ß expression in U2OS, MG63, SAOS2, U2OS/MTX300, and ZOS osteosarcoma cell lines. Nude mice (n = 5-8 mice per group) were injected with U2OS/MTX300, and ZOS cells to assess the role of GSK-3ß in osteosarcoma growth in vivo and to evaluate the effects of inhibitors and/or anticancer drugs on tumor growth. We used an antibody array, polymerase chain reaction, western blotting, and a luciferase reporter assay to establish the effect of GSK-3ß inhibition on the nuclear factor-κB (NF-κB) pathway. Immunochemistry was performed on primary tumor specimens from osteosarcoma patients (n = 74) to determine the relationship of GSK-3ß activity with overall survival. RESULTS: Osteosarcoma cells with low levels of inactive p-Ser9-GSK-3ß formed colonies in vitro and tumors in vivo more readily than cells with higher levels and cells in which GSK-3ß had been silenced formed fewer colonies and smaller tumors than parental cells. Silencing or pharmacological inhibition of GSK-3ß resulted in apoptosis of osteosarcoma cells. Inhibition of GSK-3ß resulted in inhibition of the NF-κB pathway and reduction of NF-κB-mediated transcription. Combination treatments with GSK-3ß inhibitors, NF-κB inhibitors, and chemotherapy drugs increased the effectiveness of chemotherapy drugs in vitro and in vivo. Patients whose osteosarcoma specimens had hyperactive GSK-3ß, and nuclear NF-κB had a shorter median overall survival time (49.2 months) compared with patients whose tumors had inactive GSK-3ß and NF-κB (109.2 months). CONCLUSION: GSK-3ß activity may promote osteosarcoma tumor growth, and therapeutic targeting of the GSK-3ß and/or NF-κB pathways may be an effective way to enhance the therapeutic activity of anticancer drugs against osteosarcoma.

Reduced expression of Krüppel-like factor 17 is related to tumor growth and poor prognosis in lung adenocarcinoma.

Krüppel-like factor 17 (KLF17), a new member of the Krüppel-like factors (KLFs), has been reported to be a negative regulator of epithelial-mesenchymal transition (EMT) and metastasis in breast cancer. However, the biological role and clinical significance of KLF17 in lung adenocarcinoma has been less clear. In the present study, we showed that KLF17 expression was decreased in lung adenocarcinoma. Reduced expression of KLF17 was correlated significantly with a short survival time in patients with lung adenocarcinoma (P<0.0001). Moreover, KLF17 expression was an independent prognostic indicator for patients with lung adenocarcinoma. KLF17 expression level was correlated with the tumor stage (P=0.016) and tumor size (P=0.001) in lung adenocarcinoma. Overexpression of KLF17 inhibited cell growth in A549 and PC-9 cell lines. In conclusion, it is possible that KLF17 inhibits tumor growth in lung adenocarcinoma. The reduced expression of KLF17 is a valuable prognostic indicator for patients with lung adenocarcinoma, and KLF17 could be a novel target for treatment of lung adenocarcinoma.

Clinical analysis of vascular anomalies: a hospital-based retrospective study of 592 patients in southeast China.

BACKGROUND: Vascular anomalies are common and multidisciplinary involved diseases. The greatest impediment to their treatment in the past was their confusing terminology and clinical heterogeneities. This hospital-based retrospective study assessed some clinical characteristics, diagnosis, therapies and outcomes of patients with vascular anomalies in southeast China. METHODS: A total of 592 vascular anomalies patients (patients with intracranial tissues or viscera involved were excluded), admitted to the First Affiliated Hospital of Sun Yat-sen University from January 2006 to September 2009, were enrolled in the study. Data for clinical characteristics, diagnosis, therapies and outcomes were collected and analyzed. RESULTS: Of the 592 patients, the male:female ratios in the vascular tumor group (n = 187) and the vascular malformation group (n = 405) were 1:1.49 and 1:1.06 respectively, with no significant difference between them. The mean onset age of the vascular tumor group was significantly younger than that of the vascular malformation group (p < 0.001). The head and neck were the most commonly (31.4%) involved areas in vascular anomalies. A total of 23.8% of the patients with vascular anomalies had definite symptoms caused by the vascular lesions. In the vascular tumor group, 94.1% of them were infantile hemangiomas. Venous malformation was the most common (41.0%) subtype of vascular malformations. Surgical therapy was undertaken in 94.2% of the patients with vascular anomalies. Of the 519 patients available for the 16 - 58 month follow-up, 322 patients (62.0%) were cured, 108 patients (20.8%) were markedly improved, 57 patients (11.0%) were partially improved, and 32 patients (6.2%) were uncured. CONCLUSIONS: Vascular anomalies are clinically heterogeneous. While the outcome is generally favorable, further effort should be made to determine the appropriate terminology and management.

[Effect of Epstein-Barr virus-encoded latent membrane protein 1 on ß-catenin transcriptional activity and expression in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the contribution of latent membrane protein (LMP)1 to nasopharyngeal carcinogenesis via Wnt/ß-catenin signal pathway. METHODS: The recombinant plasmid pHA2-LMP1 was constructed; immunofluorescence staining, Dual-Luciferase Reporter Assay, Western blot and immunohistochemistry staining were used to study the effect of LMP1 on the transcriptional activity and expression of ß-catenin. RESULTS: (1) Abnormal expression of ß-catenin was obtained in 38 cases (50.7%, 38/75), LMP1 expression was obtained in 38 cases (50.7%, 38/75). There was significantly positive correlation between LMP1 expression and abnormal expression of ß-catenin in nasopharyngeal carcinoma tissue (P = 0.008). (2) The expression of ß-catenin in nuclei of NPC cell line CNE1 and CNE2 transfected with pHA2-LMP1 plasmid dramatically increased, and the expression was remarkable in poorly-differentiated NPC cell line CNE2 than that of well-differentiated CNE1 cells. (3) LMP1 expression dramatically increased the transcriptional activity of ß-catenin in CNE1 and CNE2 cells transfected with pHA2-LMP1 and was in a time-dependent. The transcriptional activity of ß-catenin was higher in poorly-defferentiated cell line CNE2 than that of well-differentiated NPC cell line CNE1. (4) LMP1 expression did not affect the total protein expression level of ß-catenin in both CNE1 and CNE2 cell lines. CONCLUSION: EB virus-encoded LMP1 may be involved in the pathogenesis of NPC via ß-catenin signal pathway.

Clinicopathological features of gastric glomus tumor.

AIM: To study the clinicopathological features of gastric glomus tumor and review the related Chinese literature published in 1990-2010. METHODS: A case of gastric glomus tumor was reported. Clinicopathological findings in 56 cases of gastric glomus tumor were analyzed. RESULTS: Gastric glomus tumor was far more common in women than in men with a female to male ratio of 1.6:1. The median age of the patients was 45 years (range 28-79 years). The patients often complained of epigastric pain and bloody stool. The tumor was located in antrum of the stomach. The greatest diameter of the tumor was 0.8-11 cm. Histologically, the tumor was comprised of nests of glomus cells surrounding the capillaries. Glomus cells were small, uniform and round. Vimentin, smooth muscle actin and actin were expressed in the tumor. Other markers, including S-100 protein, CD34, CD117, desmin, CD56, synaptophysin, chromogranin A, neuron specific enolase and cytokeratin were all negative. CONCLUSION: Gastric glomus tumor is a rare benign mesenchymal neoplasm. Its diagnosis depends on pathologic examination. Differential diagnosis includes gastrointestinal stromal tumor, paraganglioma and carcinoid tumor.

[Correlation of Epstein-Barr virus-encoded latent membrane protein 1 (LMP1) to fascin and phosphorylated Stat3 in nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Latent membrane protein 1 (LMP1) of Epstein-Barr (EB) virus is an important oncogene. Fascin is an actin cross-linking protein involved in cell migration and adhesion. Phosphorylated signal transducer and activator of transcription 3 (pStat3) is a member of STATs family, which is closely related to tumorigenesis. This study was to investigate expressions of LMP1, Fascin and pStat3 in nasopharyngeal carcinoma (NPC) tissues and lymph node metastases of NPC, thus to explore their correlations to the initiation and progression of NPC. METHODS: Expressions of EBV-encoded small RNA (EBER), LMP1, Fascin, pStat3, p53, Ki-67 and Bcl-2 were detected in 43 NPC tissues (21 with and 22 without lymph node metastases) and 21 corresponding lymph node metastases using in situ hybridization or immunohistochemistry (IHC). Data were statistically analyzed. Expressions of pStat3 and Fascin were measured in the NPC cell line CNE1 transfected with LMP1-expressing plasmid using Western blot. RESULTS: Positive EBER expression was detected in all 43 NPC tissues and 21 lymph node metastases in NPC. The expression rates of LMP1, Fascin, pStat3, p53, Ki-67, and Bcl-2 were 69.8% (30/43), 93.0% (40/43), 72.1% (31/43), 90.7% (39/43), 88.4% (38/43) and 88.4% (38/43)in 43 NPC tissues, respectively. LMP1 expression was positively correlated with the expression level of Fascin, pStat3, p53, Ki-67 and Bcl-2 in 43 NPC cases(P < 0.05). LMP1 was found in 10 out of 21 (46.7%) lymph node metastases in NPC. In addition, LMP1 expression dramatically increased pStat3 and Fascin in CNE1 cells. CONCLUSIONS: LMP1 is expressed in lymph node metastatases in NPC. The expression of LMP1 is positively correlated with Fascin, pStat3 and the proliferation index of tumor cells. Moreover, LMP1 up-regulates pStat3 and Fascin in NPC cells.

[Analysis of Epstein-Barr virus BamH I "f" variant in nodal metastasis of nasopharyngeal carcinoma].

OBJECTIVE: To investigate the Epstein-Barr virus (EBV) BamH I "f" variant in primary nasopharyngeal carcinoma (NPC) and its metastases in lymph nodes (LN). METHODS: In situ hybridization was used to detect EBV-encoded small RNA (EBER) expression in 21 paired paraffin-embedded tissue from primary NPC and their lymph node metastases and 22 primary NPC without lymph node metastasis. PCR and restriction fragment length polymorphism (RFLP) assay were used to detect EBV BamH I "f" variant in all cases of NPCs, lymph node metastases and 50 cases of chronic inflammation of nasopharynx from Canton. RESULTS: All cases of NPCs and their lymph node metastases showed EBER expression, indicating a high EBV-positive rate in Cantonese NPC patients. EBV BamH I "f" variant was found in 11 cases (52.4%, 11/21) of primary NPCs with LN metastasis, 12 cases (57.1%, 12/21) of the LN metastases, and 18 cases (81.8%, 18/22) of primary NPCs without LN metastasis. However, of the 50 cases of chronic inflammation of nasopharynx, only one case (2.1%, 1/47) demonstrated BamH I "f" variant. The frequency of BamH I "f" variant in NPC was therefore dramatically higher than that in chronic inflammation of nasopharynx. It is of note that atypical hyperplasia was observed in a few epithelial cells from the case of chronic inflammation of nasopharynx expressing BamH I "f" variant. CONCLUSIONS: The frequency of EBV BamH I "f" variant in NPC is significantly higher than that in chronic inflammation of nasopharynx. It is the first demonstration that the BamH I "f" variant is also present in the LN metastases of NPC. The frequency of BamH I "f" variant in metastatic NPC of the lymph node is almost equal to that of primary NPCs.

[Detection of cytokeratin 19 and thyroperoxidase expressions in the diagnosis of thyroid diseases].

OBJECTIVE: To investigate the value of detecting cytokeratin 19(CK19) and thyroperoxidase (TPO) expression in the diagnosis of thyroid diseases including thyroid carcinoma, multinodular goiter, adenoma and Hashimoto thyroiditis. METHODS: SP immunohistochemistry was used to detect the expressions of CK19 and TPO in paraffin-embedded thyroid tissue specimens obtained from 62 patients with thyroid carcinoma (30 with papillary carcinomas, 22 with follicular variant of papillary carcinomas, and 10 with follicular carcinomas) and 44 with benign thyroid diseases (including 22 with multinodular goiters, 14 with adenoma, and 8 with Hashimoto thyroiditis). RESULTS: CK19 expression was detected in 96.8% of the thyroid carcinomas and in 4.5% of benign thyroid diseases, demonstrating a significant difference in CK19 expression between the two thyroid diseases (P<0.01). TPO expression was found in 100% of benign thyroid disease and in 3.2% of thyroid carcinoma, showing also a significant difference between them (P<0.01). CONCLUSION: CK19 and TPO can be important molecular markers for diagnosing thyroid carcinoma.

[Study of sequence variations of Epstein-Barr virus LMP1 gene in nasopharyngeal carcinoma].

OBJECTIVE: To detect the sequence variations frequently found within the N- and C-terminal regions of Epstein-Barr virus (EBV) LMP1 gene in nasopharyngeal carcinoma (NPC) and to study the underlying mechanisms. METHODS: Fresh tumor tissues were sampled from 63 patients with untreated NPC encountered in Affiliated Tumor Hospital of Sun Yat-sen University, Guangzhou. The N-terminal region of EBV LMP1 gene was amplified with nested polymerase chain reaction (PCR), followed by XhoI enzyme digestion. Nested PCR was also employed to detect the 30 base pairs deletion within the C-terminal region. Four-colored fluorescence terminator sequencing method was applied for bi-directional solid-phase sequencing of the 8 representative PCR products in 4 cases of NPC. The DNA sequence within the N- and C-terminal regions of LMP1 gene was then analyzed. RESULTS: There were 4 patterns of sequence variations, namely, wt-XhoI/wt-LMP1 (4 cases, 6.3%), wt-XhoI and XhoI-loss/del-LMP1 (4 cases, 6.3%), wt-XhoI/del-LMP1 (5 cases, 7.9%) and XhoI-loss/del-LMP1 (50 cases, 79.5%), detected in the 63 studied cases. Sequence analysis showed that the EBV LMP1 gene had underwent non-synonymous and synonymous substitutions, as compared with the prototype of B95-8 cells. The ratio of non-synonymous to synonymous substitutions was 2.25. CONCLUSIONS: XhoI-loss/del-LMP1 is the predominant sequence variation pattern of EBV LMP1 gene in NPC from Guangzhou. The XhoI-loss variation seems to develop on top of del-LMP1. When compared with the EBV LMP1 gene in peripheral blood B-lymphocytes of virus carriers and in preinvasive epithelial lesions (reported previously), it is likely that the sequence variation patterns of LMP1 gene may represent 4 different phases of intrahost evolution of EBV during nasopharyngeal carcinogenesis.

[Clinical value of vascular endothelial growth factor detection in forecasting distant metastasis risk of nasopharyngeal carcinoma].

BACKGROUND & OBJECTIVE: Vascular endothelial growth factor (VEGF)closely relates with the malignancy and metastasis of various kinds of cancers. This study was designed to evaluate the value of VEGF detection in forecasting distant metastasis risk of nasopharyngeal carcinoma(NPC)patients. METHODS: Tumor biopsies,and serum specimens were collected before treatment from 59 pathologically diagnosed NPC patients, hospitalized in our hospital from Mar. 1999 to Feb. 2000. Immunohistochemistry LSAB method was used to detect VEGF in NPC tissues. VEGF in NPC serum was detected by quantitative enzyme-linked immunosorbent assay (ELISA) method. Through follow-up study, the relationship between VEGF and distant metastasis of NPC patients was observed. RESULTS: The expression of VEGF in NPC tissue,and serum positively related with the distant metastasis (P< 0.05). Non-distant metastasis survival rates of different tissue VEGF groups were 100%(-), 95.24%(+), 65.19%(++), and 58.93%(+++), significant difference existed between every 2 groups (P=0.019 3). Non-distant metastasis survival rates of different serum VEGF groups were 82.57% (< 466.78 ng/L), and 59.11% (>/=466.78 ng/L)(P=0.021 1). Multi-prognostic factors analysis showed that VEGF expression in NPC tissue and serum had significant effects on distant metastasis of NPC. CONCLUSIONS: The detection of VEGF either in NPC tissue or in serum could be regarded as a valuable indicator for predicting distant metastasis risk of NPC patients. Combined detection of them could increase the chances of forcasting distant metastasis in NPC patients.

Loss of an XhoI-site within N-terminal region of Epstein-Barr virus LMP1 gene in nasopharyngeal carcinoma.

BACKGROUND & OBJECTIVE: It is well known that Epstein-Barr virus(EBV) LMP1 gene is involved in nasopharyngeal carcinogenesis. This research was designed to investigate the loss of an Xho I-site within the N-terminus of Epstein-Barr virus(EBV) latent membrane protein 1(LMP1) gene isolated from nasopharyngeal carcinoma (NPC) in Guangdong for further understanding the sequence variation of LMP1 gene involved in carcinogenesis. METHODS: Sixty-three fresh nasopharyngeal biopsies taken from the patients with nasopharyngeal carcinoma were collected in Cancer Center of Sun Yat-sen University. The peripheral blood mononuclear cells (PBMCs) obtained from 10 healthy EBV carriers were as control. The QIAamp DNA Mini Kits were used for extracting the DNA of biopsies and PBMCs. The N-terminus of EBV LMP1 gene was amplified using nested polymerase chain reaction (PCR) and then followed by Xho I enzyme digestion. Bidirectional solid-phase sequencing of the PCR products was performed using four-colored fluorescence terminator sequencing method. RESULTS: No loss of an Xho I-site within N-terminus of EBV LMP1 gene (wt-Xho I) was detected in PBMCs of all 10 carriers. The loss of an Xho I-site (Xho I-loss) was demonstrated in 50 cases (50/63, 79.36%) and the partial loss was demonstrated in 4 cases (4/63, 6.35%). The loss of an Xho I-site was not found in 9 cases (9/63, 14.29%). Besides loss of an Xho I-site (nt:169423-169428; GAGCTC --> GATCTC), 4 additional missense point mutations were found. CONCLUSION: According to the results obtained from this investigation, the PBMCs of 10 EBV carriers residing in Guangdong merely contain EBV variant with wt-Xho I. On the contrary, the EBV variant with XhoI-loss becomes the predominant variant detected in NPC tissues. So, the genomic variation within N-terminus (loss of an Xho I-site and other missense point mutations) of EBV LMP1 gene might be developed in the process of nasopharyngeal carcinogenesis.

[Analysis of Epstein-Barr virus with BamHI "f" variant and XhoI-loss of LMP1 gene in nasopharyngeal carcinoma].

OBJECTIVE: To investigate the genomic variation of Epstein-Barr virus (EBV) and its significance in nasopharyngeal carcinogenesis. METHODS: Forty nasopharyngeal carcinoma (NPC) biopsy tissues were used for detection of EBV BamHI f variant and LMP1 XhoI-loss by polymerase chain reaction (PCR), nested PCR, and RFLP (restriction fragment length polymorphism). Forty-eight samples of peripheral blood mononuclear cells (PBMC) taken from apparently healthy adult individuals were used for detection of LMP1 XhoI-loss. Three samples of amplified LMP1 exon 1 DNA from B95-8 cell line and 2 NPC tissues (one having XhoI-loss and the other having Wt-XhoI/XhoI-loss) were sequenced. RESULTS: Thirty out of the 40 NPC cases (30/40, 75%) harbored EBV BamHI f variant and the remaining 10 (10/40, 25%) harbored BamHI F prototype. Thirty out of the 39 NPCs (30/39, 76.9%) showed single EBV LMP1 XhoI-loss, 7 (7/39, 18.0%) showed single LMP1 Wt-XhoI (presence of a XhoI site in exon 1 of LMP1 gene, as in B95-8 cell line), and 2 (2/39, 5.1%) showed both LMP1 Wt-XhoI and XhoI-loss. Thirty-eight of the 39 NPCs (97.4%) showed EBV LMP1 XhoI-loss or/and BamHI F variant. In the NPC tissue (1 case only) showing the prototype of Wt-XhoI/BamHI "f", there were several base substitutions, including 5 missense mutations and 2 silent mutations present in LMP1 exon 3, on DNA sequencing. On the other hand, 10 out of the 48 samples of PBMC taken from apparently healthy individuals could be amplified successfully by nested PCR for detection of LMP1 XhoI site. All of these 10 samples carried the prototype of EBV LMP1 Wt-XhoI. CONCLUSIONS: The majority of EBV present in neoplastic cells of NPC is of BamHI "f" variant and/or possesses LMP1 XhoI-loss, as compared with that in healthy individuals. This genomic variation of EBV may bear some roles in the development and progression of NPC.