Genetic factors leading to chronic Epstein-Barr virus infection and nasopharyngeal carcinoma in South East China: study design, methods and feasibility.

Nasopharyngeal carcinoma (NPC) is a complex disease caused by a combination of Epstein-Barr virus chronic infection, the environment and host genes in a multi-step process of carcinogenesis. The identity of genetic factors involved in the development of chronic Epstein-Barr virus infection and NPC remains elusive, however. Here, we describe a two-phase, population-based, case-control study of Han Chinese from Guangxi province, where the NPC incidence rate rises to a high of 25-50 per 100,000 individuals. Phase I, powered to detect single gene associations, enrolled 984 subjects to determine feasibility, to develop infrastructure and logistics and to determine error rates in sample handling. A microsatellite screen of Phase I study participants, genotyped for 319 alleles from 34 microsatellites spanning an 18-megabase region of chromosome 4 (4p15.1-q12), previously implicated by a linkage analysis of familial NPC, found 14 alleles marginally associated with developing NPC or chronic immunoglobulin A production (p=0.001-0.03). These associations lost significance after applying a correction for multiple tests. Although the present results await confirmation, the Phase II study population has tripled patient enrollment and has included environmental covariates, offering the potential to validate this and other genomic regions that influence the onset of NPC.

[Association study of chromosome 4 STRs polymorphisms with nasopharyngeal carcinoma].

Nasopharyngeal carcinoma (NPC) is a complex disease caused by an interaction of EBV chronic infection, environment and host genes, in a multi-step process of carcinogenesis. However, which genetic factors play an important role in the development of chronic EBV infection and NPC remain elusive. The objective of this study is to identify genetic variations associated with two key clinical stages of NPC development: persistent Epstein-Barr virus (EBV) infection of nasopharyngeal epithelia and progression to NPC. We inspected a NPC-associated region on the short arm of chromosome 4 previously implicated by a genome-wide linkage analysis of familial NPC. We determined genotypes for 319 alleles in 34 microsatellite markers spanning an 18 Mb region in 350 NPC cases, 288 individuals with IgA antibodies to EBV capsid antigen (IgA/VCA+) and 346 controls seronegative for IgA antibodies to EBV capsid antigen (IgA/VCA-). The cases and controls were Han Chinese from Wuzhou city and Cangwu County, Guangxi province where the incidence of NPC is as high as 25-50 per 100,000 individuals. Comparing NPC cases to IgA/VCA+ subjects, we found 9 alleles marginally associated with developing NPC from IgA+ status, 5 for risk (OR=1.51-5.36, P=0.01-0.03) and 4 for restrictive (OR=0.3-0.71, P=0.02-0.045). Comparing IgA/VCA+ subjects and IgA/VCA- controls, and comparing all IgA seropositives with and without NPC to IgA seronegatives revealed 12 significant and 3 highly significant (P<0.01) alleles associated with IgA+ serostatus in the two comparing groups. Alleles D4S3241-136 (P=0.004, OR=1.91, 95% CI=1.2-3.0) and D4S3347-213 (P=0.001, OR=1.6, 95% CI=1.2-2.1) were for risk. Allele D4S174-202 (P=0.001, OR=0.5, 95%CI=0.3-0.7) was restrictive. However, statistical significance was lost for all when corrected for multiple comparisons test. Our study could not affirm the genetic association within this region with NPC as did another pedigree study, but provide an opportunity for further gene discovery in this highly endemic NPC population and suggest that this region warrants further study.

[Studies on transformation of human esophageal fibroblasts mediated by a retroviral vector containing the E6E7 ORFs of human papillomavirus type 16].

OBJECTIVE: To study the etiological role of human papillomavirus type 16 (HPV16) infection in the development of esophageal cancers. METHODS: A recombinant retrovirus containing the E6E7 ORFs of HPV16 was packaged and human fetal esophageal fibroblasts were infected. The tumorigenecity of the fibroblasts was tested in SCID mice in synergy with 12-O-tetradecanoylphorbol-13-acetate (TPA). RESULTS: Human esophageal fibroblasts infected with the recombinant retrovirus induced sarcomas in SCID mice, the existence and expression of E6E7 ORFs was confirmed in the sarcomas. Fibroblasts cultured from the sarcoma were demonstrated heteroploid by cytoflowmetry. However, tumors were not observed in human fetal esophagus infected with such virus. CONCLUSIONS: These results revealed that the established recombinant retroviral system can successfully mediate the transference of HPV16 E6E7 genes, and such system is applicable to researches on tumorigenesis of HPV.

[Sequence analysis of the deletion and mutation in carboxy terminal region of the Epstein-Barr virus latent membrane protein 1 derived from nasopharyngeal carcinoma patients].

BACKGROUND: To study the deletion and mutation in carboxy terminal region of LMP1 gene derived from nasopharyngeal carcinoma (NPC) in Guangdong and Guangxi, the high risk areas of nasopharyngeal carcinoma in China. METHODS: LMP1 gene carboxy terminal region was amplified from nasopharyngeal carcinoma tissues by PCR, and then cloned and sequenced. RESULTS: Of the 20 cases, 17 were LMP1 positive. In all positive cases, only 1 case did not show deletion. Four positive cases were chosen for DNA sequencing, The rusult showed that all the four cases had mutation and the 30bp deletion. CONCLUSIONS: High frequency of deletion and mutation in LMP1 gene of nasopharyngeal carcinoma tissues was found in Guangdong and Guangxi. Whether it related to the high incidence of NPC should be further studied.

[Detection of Epstein-Barr virus in T cell lymphoma and clinicopathologic analysis].

BACKGROUND: To study the relationship of Epstein-Barr virus (EBV) and T cell lymphoma. METHODS: Sixty cases of T cell lymphomas were examined for the presence of EBV using in situ hybridization for EBV encoded RNA (EBERs). RESULTS: EBERs were detected in tumor cells in 37(69.8%) of 53 cases with peripheral T cell lymphoma, but in none of seven cases of precursor T lymphoblastic lymphoma. The total detected EBERs were 37(61.6%) in 60 cases of T cell lymphomas. By Revised European-American Lymphoma(REAL) classification, EBERs were detected in 2/2 angioimmuno-blastic T cell lymphoma,17/18 angiocentric lymphoma, 4/6 anaplastic large cell lymphoma and 14/27 peripheral T cell lymphoma, unspecified (51.9%). The frequency of EBERs among the extranodal peripheral T cell lymphoma was higher than the nodal (P less than 0.01) there was no significant correlation with the sex, age and clinical stage. CONCLUSIONS: This study indicated that high incidence of EBV was observed in peripheral T cell lymphoma, with predilection for angiocentric lymphoma and extranodal presentation.

[Identification and assessment of multiple human papillomavirus types in condyloma acuminata lesions from patients with genital warts in Beijing area].

OBJECTIVE: To identify and assess multiple human papillomavirus types in condyloma acuminatum lesions from patients with genital warts in Beijing area, and compare different features between otherwise healthy and immunosuppressed patients. METHODS: PCR, RFLP and nucleotide sequencing analysis were used to determine HPV types from individual lesions. RESULTS: The predominant type from other healthy patients was HPV6, secondly HPV11. The mean age of patients infected by HPV6 was lower than that of HPV11 and HPV6 + 11. While lesions from immunosuppressed patients were often contained HPV11 or mixed with HPV6. Besides, HPV types 16 and 53 were detected from infected lesions than other HPV types. CONCLUSIONS: HPV6 was the major pathogen of condyloma acuminatum, but infected patients were at lower ages. While HPV11 was most often detected from immunosuppressed patients. As a low risk virus in normal genital tract, HPV53 also could be a pathogen in genital warts.