ABSTRACT
Matrix metalloproteinase 2 (MMP2) has been shown to play an important role in several steps of cancer development. The -1306C/T polymorphism of the MMP2 gene displays a strikingly lower promoter activity than the T allele, and the CC genotype in the MMP2 promoter has been reported to associate with the development of several cancers. To assess the contribution of the MMP2 -1306C/T polymorphism to the risk of nasopharyngeal carcinoma (NPC), we conducted a case-control study and analyzed MMP2 genotypes in 370 patients with NPC and 390 frequency-matched controls using real-time PCR-based TaqMan allele analysis. We found that subjects with the CC genotype had an increased risk (OR = 1.55, 95% CI = 1.05-2.27) of developing NPC compared to those with the CT or TT genotypes. Furthermore, we found that the risk of NPC was markedly increased in subjects who were smokers (OR = 15.04, 95% CI = 6.65-33.99), heavy smokers who smoked ≥ 20 pack-years (OR = 18.66, 95% CI = 7.67-45.38), or young (<60 years) at diagnosis (OR = 1.52, 95% CI = 1.01-2.29). Our results provide molecular epidemiological evidence that the MMP2 -1306C/T promoter polymorphism is associated with NPC risk, and this association is especially noteworthy in heavy smokers.
Subject(s)
Adult , Female , Humans , Male , Middle Aged , Asian People , Genetics , Carcinoma , Case-Control Studies , China , Epidemiology , Genetic Predisposition to Disease , Genotype , Matrix Metalloproteinase 2 , Genetics , Nasopharyngeal Neoplasms , Epidemiology , Genetics , Pathology , Neoplasm Staging , Polymorphism, Single Nucleotide , Promoter Regions, Genetic , Real-Time Polymerase Chain Reaction , Risk Factors , SmokingABSTRACT
Epstein-Barr virus (EBV) nuclear antigen 1 (EBNA1) has an instrumental role in maintaining EBV latent infection by controlling EBV episome replication and regulating viral transcription. It is a ubiquitously expressed protein during latent viral infection and in EBV-associated tumors. The EBNA1 C-terminus interacts functionally with the Qp and Cp that control viral gene expression in latency I/II and III, respectively. EBNA1 has been classified into five subtypes due to sequence variation in the DNA-interacting C-terminus. By DNA sequence analysis of its C-terminus, we detected a main sub-variant (V-val-v1) of EBNA1 with valine located in both positions 487 and 528 from matched samples including NPC biopsies and peripheral blood taken from Vietnamese (9), Chinese (12) NPC patients and healthy donors (5). In the FR-region of oriP from nine NPC biopsies from Vietnam we also frequently found substitutions, deletions and variable numbers of repeats. Using a luciferase reporter system, EBNA1 and FR both derived from Asian isolates induced higher transcriptional activity than those from B95-8 virus.
Subject(s)
Epstein-Barr Virus Infections/virology , Epstein-Barr Virus Nuclear Antigens/metabolism , Genetic Variation , Herpesvirus 4, Human/genetics , Nasopharyngeal Neoplasms/virology , Transcriptional Activation , Amino Acid Sequence , Base Sequence , Binding Sites , Cell Line , China , Epstein-Barr Virus Nuclear Antigens/chemistry , Epstein-Barr Virus Nuclear Antigens/genetics , Genes, Reporter , Herpesvirus 4, Human/classification , Herpesvirus 4, Human/isolation & purification , Humans , Mutation , Response Elements , Sequence Alignment , Sequence Analysis, DNA , Trans-Activators/chemistry , Trans-Activators/genetics , Trans-Activators/metabolism , VietnamABSTRACT
<p><b>OBJECTIVE</b>To investigate the loss of heterozygosity (LOH) on chromosomal arms 13q and 14q in nasopharyngeal carcinoma (NPC) using 21 microsatellite polymorphic markers and to study whether there is a correlation between LOH and clinicopathologic parameters and/or Epstein-Barr virus (EBV) infection in NPC.</p><p><b>METHODS</b>Sixty cases of NPC were studied using polymerase chain reaction based microsatellite analysis with genescan and genotyping techniques.</p><p><b>RESULTS</b>LOH was detected on 13q in 78% of NPC tumors, high frequency LOH loci (more than 30%) clustered to 13q12.3-q14.3 and 13q32. On chromosome 14q, LOH was detected in 80% of NPC tumors; high frequency LOH loci clustered to 14q11-q13, 14q21-q24 and 14q32. High frequency LOH at 13q31-q32 correlated with a lower level of EBV infection; LOH on chromosome 14q was closely associated with poor differentiation of NPC tumor cells.</p><p><b>CONCLUSION</b>Our results suggest that in NPC, LOH on chromosome 13q and 14q are common genetic events, and putative tumor suppressor genes (TSG) residing in these regions may be involved in tumorigenesis.</p>
