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Biomedical subjects

Yun Ma

Publications and source records attributed to Yun Ma.

At least 37 records · Page 2Linked to original sources
PubMed2005

Susceptibility to thyroid disorders in hepatitis C.

BACKGROUND & AIMS: Autoimmune thyroid disorders (AITDs) are reported, especially during interferon treatment, in chronic HCV infection, in which non-organ-specific autoantibodies (NOSAs) are common. We wondered whether seropositivity for NOSA is associated with susceptibility to AITDs. METHODS: We evaluated thyroid function and antithyroglobulin and antithyroperoxidase antibodies in 348 Italian patients with chronic hepatitis C (34% NOSA-positive), 196 patients (33% NOSA-positive) of whom received interferon treatment. RESULTS: At baseline, thyroid disorders were significantly more frequent in liver/kidney microsomal antibody type 1 (LKM1)-positive patients (29% vs 9%, P < .005). Similarly, on interferon therapy de novo autoimmune thyroid markers and/or symptomatic thyroid disorders appeared more often in LKM1-positive patients (50% vs 3%, P < .0001). Both female sex and LKM1 positivity were predictors of AITD, but only the latter remained significant after logistic regression analysis. Cross-reactivity to all 7 linear epitopes encoding homologous amino acid sequences shared by the HCV polyprotein, CYP2D6 (the LKM1 autoantigen), and thyroperoxidase was detected in 86% LKM1-positive HCV patients with clinical thyroid disorders, but in none of the LKM1-positive or negative HCV patients without thyroid disease, and none of an HCV-negative control group comprising subjects with LKM1-positive autoimmune hepatitis or AITD without liver disease ( P < .0001). CONCLUSIONS: Patients receiving interferon therapy for hepatitis C seropositive for LKM1 are susceptible to develop AITDs, in association with treatment. Molecular mimicry and epitope spreading are potential pathogenic mechanisms.

Adolescent↗
PubMed2005

A study of molecular mimicry and immunological cross-reactivity between hepatitis B surface antigen and myelin mimics.

On the basis of the reported association between hepatitis B vaccination (HBvacc) and autoimmune demyelinating complications such as multiple sclerosis (MS), we have looked for aminoacid similarities between the small hepatitis B virus surface antigen (SHBsAg), and the MS-autoantigens myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG) that could serve as targets of immunological cross-reactivity. Twenty-mer peptides spanning 4 SHBsAg/MOG and 1 SHBsAg/MBP mimicking pairs, were constructed and tested by ELISA as targets of cross-reactive responses. A total of 147 samples from 58 adults were collected before HBvacc (58/58), and post-HBvacc (48/58 before the second and 41/58 before the third boost). Eighty-seven sera from anti-SHBsAg antibody negative patients with various diseases were tested as pathological controls. Reactivity to at least one of the SHBsAg peptides was found in 8 (14%) pre-HBvacc subjects; amongst the remaining 50, reactivity to at least one of the SHBsAg peptides appeared in 47 (94%) post-HBvacc. Reactivity to at least one of the MOG mimics was present in 4 (8%) pre-HBvacc and in 30 (60%) post-HBvacc (p < 0.001). Overall 30/50 (60%) vaccinees had SHBsAg/MOG double reactivity on at least one occasion compared to none before-vaccination and in 2 (2%) of the pathological controls (p < 0.001 for both). SHBsAg/MOG double reactivity was cross-reactive as confirmed by inhibition studies. At 6 months post-vaccination, 3 of the 4 anti-MOG reactive cases before vaccination and 7 of the 24 (29%) of the anti-MOG reactive cases at 3 months post-vaccination had lost their reactivity to MOG5-24. There was no reactivity to the SHBsAg/MBP mimics. None of the vaccinees reported symptoms of demyelinating disorders. In view of the observed SHBsAg/MOG cross-reactivity, the vaccine's possible role as an immunomodulator of viral/self cross-reactivity must be further investigated.

Adult↗
PubMed2005

[Changtong oral liquid for prevention of postoperative intestinal adhesion: an experimental study].

OBJECTIVE: To observe the effect Changtong oral liquid (CTOL), a traditional Chinese drug preparation, on the prevention of postoperative intestinal adhesion. METHODS: Fifty-four male SD rats were randomly divided into 6 equal groups, namely the normal control, model control, Simo decoction (SMD, another traditional Chinese drug preparation), and CTOL groups, and CTOL group included three subgroups treated at low, moderate and high doses. Except for those in the normal control group, all the other rats were subjected to operation with Ellis' method for establishing intestinal adhesion models. After the operation, the rats in the normal control and model groups received intragastric administration of distilled water (10 ml/kg), SMD group received SMD administration in similar manner at the dose of 10 ml/kg, and the three CTOL groups had CTOL at the doses of 4.3, 8.6 and 17.2 g/kg, respectively. On day 7 after surgery, blood sample were taken from all the rats to determine the white blood cell (WBC) count and fibrinogen (FIB) concentrations, and the intestinal adhesion was graded. RESULTS AND CONCLUSION: CTOL evidently reduced the severity of postoperative adhesion and decreased WBC count and plasma FIB level, suggesting the efficacy of CTOL in inhibiting the formation of postoperative intestinal adhesion.

Abdomen↗
PubMed2005

[Vascular endothelial growth factor expression and microvessel density in stage I-II non-small cell lung cancer and their prognostic significances].

BACKGROUND & OBJECTIVE: TNM staging system is used widely to predict prognosis of non-small cell lung carcinoma (NSCLC) patients, but patients with the same stage may have very different survivals; better prognostic index is needed. Angiogenesis is considered to be essential for tumor development, progression, and metastasis, but the prognostic impacts of vascular endothelial growth factor (VEGF) and microvessel density (MVD) in NSCLC is controversial. This study was to evaluate the prognostic value of VEGF and MVD in NSCLC. METHODS: VEGF and MVD in 214 specimens of stageI-II NSCLC (20 in stage IA, 137 in stage IB, and 57 in stage IIB) were detected by tissue chip and SP immunohistochemistry. No patient underwent postoperative antitumor treatment. RESULTS: VEGF expression didn't relate to gender, age, blood type, pathologic type, and TNM stage (P0.05). MVD correlated with age and pathologic type (P0.05), but did not relate to gender, blood type, and TNM stage (P0.05). The mean value of MVD was 65.8+/-5.2 in VEGF-low patients, and 67.5+/-2.5 in VEGF-high patients (P0.05). The 5-year survival rate was significantly lower in MVD-high patients than in MVD-low patients (34.5% vs. 60.0%, P=0.013). Furthermore, multivariate Cox regression analysis showed that MVD (P=0.000) was an independent prognostic factor of NSCLC. CONCLUSION: High MVD closely relates to poor prognosis of stageI-II NSCLC.

Adolescent↗
PubMed2005

[Transplantation of mouse bone marrow mesenchymal stem cells into the xenogeneic testis].

OBJECTIVE: To study transplantation of mouse bone marrow mesenchymal stem cells (MSCs) into the xenogeneic testis. METHODS: (1) The tibias and femurs were dissected from 5-6-week-old mice. The marrow in the tibias and femurs was flushed out with medium. MSCs were isolated, cultured and purified in vitro by Percoll density gradient centrifugation combined with adherent method. (2) MSCs of the third generation were adopted and marked with Hoechest33342 for observation, and then made into cell-suspending fluid. (3) The marked MSCs were transplanted into the testis of the xenogeneic mouse by testis net injection. The biopsies of the testis tissues were carried out at different time and made into frost slices at three sites for observation. RESULTS: (1) A lot of purified MSCs were obtained at the third generation. (2) The nucleoli of the marked MSCs showed light-yellow under the fluoroscope. (3) Xenogeneic transplantation of mouse bone marrow MSCs by testis net injection was successful, without immunoreaction. On the 1 st day after transplantation, MSCs only concentratively distributed in the medial slices, the nucleoli being light-yellow; On the 1 st and 3 rd day, MSCs dispersively distributed in the medial slices; On the 6th, 9th and 12th day, MSCs presented in all the slices of the three sites, some ranging tubally; On the 15th and 18th day, the fluorescence of MSCs weakened; On the 21 st day, the fluorescence of MSCs disappeared. CONCLUSION: Transplantation of mouse bone marrow MSCs into the xenogeneic testis by testis net injection is effective and feasible, without immunoreaction. MSCs can survive after transplantation.

Animals↗
PubMed2005

Phosphorus removal by the multipond system sediments receiving agricultural drainage in a headstream watershed.

Wetland systems in headstream watersheds are important to control the nonpoint source pollutant phosphorus. Experiments were conducted using intact sediment-water columns obtained from the multipond system in Liuchahe watershed of Chaohu Lake to determine its capacity to retain P. It was found that pond sediments had strong P retention ability. For the Hill pond, Village pond and Rice pond, their retention coefficient(A) were 288.3, 279.2 and 260.8 L/m2, respectively. The equilibrium P concentration (EPCw) were 0.016, 0.028 and 0.018 mg/L, respectively. The Hill pond indicated the highest P retention ability. P retained in the pond sediments indicated high stable degree. P removal from the overlying water column into the pond sediments followed a first-order kinetic model. Under the experimental hydrological conditions, the retention time had a positive correlation with the P loading. The multipond system could provide enough retention time to retain P in drainage runoffs. At the P levels evaluated, the sediments of the multipond system are effective sinks to retain P from nonpoint source runoffs.

China↗
PubMed2005

[A study about the association of detoxication gene GSTM1 polymorphism and the susceptibility to aflatoxin B1-related hepatocellular carcinoma].

OBJECTIVES: To investigate the association between susceptibility to aflatoxin B1(AFB1)-related hepatocellular carcinoma (HCC) and the polymorphism of detoxication gene GSTM1. METHODS: The peripheral white blood cell DNA samples were obtained from all the subjects including 140 HCC cases and 536 controls from an AFB1 high risk area in Guangxi province. The GSTM1 polymorphism was detected using PCR technique. RESULTS: (1) The GSTM1-present was associated with a decreased HCC risk. The GSTM1-null was associated with an increased HCC risk [adjusted OR (95% CI)= 2.07 (1.20-3.57)]. (2) In the cohorts of both low/median and high exposure levels of AFB1, GSTM1-null genotype was associated with a conspicuous significantly increased risk for HCC [adjusted OR (95% CI) = 1.92 (0.92-4.00) and 1.80 (0.77-4.17)]. CONCLUSION: The results suggest that genetic polymorphism of GSTM1 was susceptible to HCC and individuals who are GSTM1-null have an increased risk of developing HCC. There is evidence of interaction between GSTM1 polymorphism and AFB1 exposure, especially with low/median degrees of AFB1 exposure.

Aflatoxin B1↗
PubMed2005

[Phosphorus sorption capacities of the pond sediments in a headstream agricultural watershed].

The land uses in watersheds have important influence on the sediments of lakes and wetlands. Field and laboratory experiments were conducted to research the phosphorus adsorption by the pond sediments in the pond system in a headstream watershed. Being scattered in different ambient land uses and receiving soil particles from various sources, the pond system provides an excellent research example for the phosphorus sorption characteristics. It was found that the pond sediments had strong phosphorus sorption capacities. The phosphorus adsorption maximum (Smax) ranged from 228 to 974 mg x kg(-1), equilibrium phosphorus concentration (EPC0) ranged from 0.004 to 0.032mg L(-1). The mean degree of phosphorus saturation (DPS) of the pond sediments was only 9.5%. The situation of the ponds can influence the physico-chemical properties of sediments and their sorption characteristics. For Smax, Hill pond >Nonirrigation pond> Rice pond> River pond> Village pond. On the contrary, for EPC0, Hill pond< Nonirrigation pond< Rice pond < River pond < Village pond. The phosphorus adsorption maximum (Smax) was significantly correlated ly correlated with the KCl-extractable phosphorus (KCl-P, r2 = 0.83, p < 0.001). Multiple regression analysis shows that Fe(ox) and KCl-P are the key factors, which can influence phosphorus sorption of the pond sediments.

Adsorption↗
PubMed2005

[Enantioselective degradation of 2, 4-dichlorprop methyl ester by sediment bacteria].

Enantioselective Degradation of 2,4-Dichlorprop methyl ester was studied by sediment bacteria. One DCPPM-degrading bacteria stain was isolated from contaminated sediments. The EF values were determined by chiral GC. The enantioselectivity of DCPPM biodegradation in aquatic phases were evaluated. Incubation with DCPPM-degrading bacteria show that the R enantiomer was preferentially degraded over the corresponding S enantiomer of DCPPM. The EF values show a much higher deviation. It indicate that the microbial degradation of DCPPM was enantioselectivety.

2,4-Dichlorophenoxyacetic Acid↗
PubMed2005

[Effect of the Yifuning soft gelatin capsules on estrogen receptor and nitric oxide levels in ovariectomized rats].

OBJECTIVE: To investigate the effects of the Yifuning soft gelatin capsules(YFN)on estrogen receptor (ER) and nitric oxide (NO) levels in ovariectomized rats. METHOD: Fifty female mature sprague-dawley rats were randomly divided into 5 groups: normal control; model control; diethylstilbestrol tablets (DT); YFN (high dose and low dose). After 4 weeks' treatment, the serum E2 levels were detected by radioimmunoassay. The estrogen receptor (ER) levels of uterus and artery were detected with method of radioligand binding assay of receptor (RBAR). The uterus pathologic changes were investigated with light microscope. NO and NOS levels of the artery and the uterus index were detected too. RESULT: YFN can obviously improve serum E2, increase index and ER of uterus (P < 0.01 or P < 0.05), and ameliorate the uterus' pathologic changes in OVX rats. It also can increase the artery' ER, NO and NOS levels. CONCLUSION: YFN can cure the climacteric syndrome and prevent the cardiovascular disease after post-menopause.

Animals↗
PubMed2005

[Study on the detoxication gene gstM1-gstT1-null and susceptibility to aflatoxin B1 related hepatocellular carcinoma in Guangxi].

OBJECTIVE: To study the association between susceptibility to aflatoxin B1 (AFB1)-related hepatocellular carcinoma(HCC) and the null genotypes of detoxication gene gstM1 and gstT1. METHODS: Peripheral blood white blood cells DNA samples were obtained from all the subjects including 140 HCC cases and 536 controls from AFB1 high risk area Guangxi. gstM1 and gstT1 polymorphisms were detected by polymerase chain reaction technique. RESULTS: (1) gstM1- and gstT1-present were associated with decreasing risk of HCC. gstM1- and gstT1-null were associated with the increasing risk of HCC [adjusted OR (95 % CI) = 2.07 (1.20-3.57) and 1.44 (0.85-2.45), respectively]; (2) The appearance of both gstM1- and gstT1-null genotypes were more susceptible to HCC than either one of them(adjusted OR and 95% CI are 2.43 and (1.19-4.97); (3) From low/median to high level of AFB1 exposure, both gstM1- and gstTl-null genotypes were associated with significantly conspicuous increasing risk of HCC [adjusted OR(95% CI) = 12.76(5.38-30.24) and 7.82(3.61-16.90) respectively]. CONCLUSION: It was suggested that: genetic polymorphisms of gstM1 and gstT1 were susceptible to HCC; individuals who were gstM1- or gstT1-null would have an increasing risk of developing HCC while individuals with both nulls were more susceptible. There was evidence of interaction between gstM1- and gstT1-null and the level of AFB1 exposure which was associated with the increasing risk of HCC.

Adult↗
PubMed2005

[Pathology of AIDS-related lymphadenopathy: a study of 18 biopsy cases].

OBJECTIVE: To study the clinicopathologic features of acquired immunodeficiency syndrome (AIDS)-related lymphadenopathy and to elucidate the salient features helpful in achieving a correct pathologic differentiated diagnosis. METHODS: Eighteen cases of AIDS-related lymphadenopathy were retrieved from the files of the First Affiliated Hospital of Guangxi Medical University from 2001 to 2004. Histochemical stains, including periodic acid-Schiff, acid-fast, Giemsa, Grocott stains and immunohistochemistry (EnVision method), were used to detect the presence of pathogens in tissue sections and classify them. RESULTS: Fifteen of the 18 cases (83%) were stage 4 (i.e. follicular and lymphocytic depletion). Twelve cases were co-infected with Penicillium marneffei and 4 other cases with Mycobacterium, and no pathogen was found in 1. The remaining patient was complicated with diffuse large B-cell lymphoma. CONCLUSIONS: When presented in early stages, AIDS-related lymphadenopathy may be overlooked, especially in routine pathology practice. Awareness of the entity in patients with persistent fever and generalized lymphadenopathy is thus crucial. Florid infection with Penicillium marneffei is also considered as an important predictor for underlying AIDS. Thorough understanding of morphologic features of AIDS-related lymphadenopathy, including possible co-infection, is essential in arriving at the correct diagnosis.

AIDS-Related Complex↗
PubMed2004

Antibodies to soluble liver antigen and alpha-enolase in patients with autoimmune hepatitis.

BACKGROUND: Antibodies to a cytosolic soluble liver antigen (SLA) are specifically detected in patients with autoimmune hepatitis (AIH). The target of anti-SLA has been identified as a ~50 kDa UGA serine tRNA-associated protein complex (tRNP(Ser)Sec), through the screening of cDNA libraries. A recent report questioned the identity of tRNP(Ser)Sec as the real SLA antigen. The latter study identified alpha-enolase as a major anti-SLA target, through proteomic analysis. METHODS: In an attempt to explain the observed discrepancy we have investigated reactivity of SLA positive sera against alpha-enolase and tRNP(Ser)Sec using rat and primate liver homogenate and the recombinant antigens. Thirty-three serum samples, 11 from SLA-positive patients and 22 from SLA negative controls were investigated. SLA antibodies were detected by an inhibition ELISA and confirmed by immunoblot using human liver homogenate. Autoantibody reactivity was further evaluated using preparations of primate and rat liver homogenates. Anti-alpha-enolase antibody reactivity has been tested by immunoblot using recombinant alpha-enolase. An affinity purified goat polyclonal anti-alpha-enolase IgG antibody was used as reference serum sample. Anti-tRNP(Ser)Sec antibody reactivity was detected by ELISA or dot blot using recombinant tRNP(Ser)Sec antigen. RESULTS AND DISCUSSION: The affinity purified IgG antibody directed to human alpha-enolase gave a band of approximately 48 kDa in both human and rat liver homogenates. A high titre anti-tRNP(Ser)Sec antibody serum gave a single band of ~50 kDa in both liver preparations. All but one anti-SLA antibody positive sera reacted with a ~50 kDa but none immunofixed a 48 kDa band. All anti-SLA antibody positive sera reacted strongly with the recombinant full length tRNP(Ser)Sec protein. None of the anti-SLA negative sera reacted with tRNP(Ser)Sec. Anti-SLA positive, and anti-SLA negative sera reacted equally against recombinant alpha-enolase by immunoblot. Pre-incubation of anti-SLA positive sera with tRNP(Ser)Sec completely abolished the 50 kDa band. The findings of the present study indicate that alpha-enolase and tRNP(Ser)Sec are both expressed in primate and rat liver and have a respective MW of 48 and 50 kDa. They also show that anti-tRNP(Ser)Sec - but not anti-alpha-enolase - correlates with anti-SLA antibody reactivity. CONCLUSION: Our findings indicate that tRNP(Ser)Sec is the most likely target of anti-SLA.

Journal Article↗
PubMed2004

Disease-specific cross-reactivity between mimicking peptides of heat shock protein of Mycobacterium gordonae and dominant epitope of E2 subunit of pyruvate dehydrogenase is common in Spanish but not British patients with primary biliary cirrhosis.

Previous studies on Spanish patients with Primary Biliary Cirrhosis (PBC) have shown extensive, disease-specific cross-reactivity between the 65-kDa heat shock protein (hsp65) of Mycobacterium gordonae and pyruvate dehydrogenase complex-E2 (PDC-E2), the major target of anti-mitochondrial antibody (AMA). Studies on a British population were unable to substantiate these findings. Having found that there is an excellent and almost unique match between the PDC-E2 autoepitope and a sequence in mycobacterial hsp65s, we tested the corresponding peptides by ELISA for cross-reactivity using sera from 90 PBC patients, 40 Spanish and 50 British, and 84 pathological controls. Reactivity to the MYCGO hsp65(90-104)/human PDC-E2(212-226)pair was present in 19 (47.5%) Spanish PBC patients and in 2 (4%) of the 50 British. Reactivity was not seen in any of the controls. Simultaneous reactivity to mimics was due to cross-reactivity as confirmed by inhibition studies. Three dimensional modelling predicts mycobacterial hsp65(90-104)to be exposed on the surface of the protein. The affinity of anti-hsp65(90-104)antibody was higher than that of anti-PDC-E2(212-226). Hsp65(90-104)is a target of disease-specific cross-reactivity to PDC-E2(212-226). The geographical confinement of this phenomenon is probably the result of complex genetic, environmental and immunological interaction.

Adult↗
PubMed2004

Impairment of CD4(+)CD25(+) regulatory T-cells in autoimmune liver disease.

BACKGROUND/AIMS: CD4(+) lymphocytes constitutively expressing the IL-2-receptor alpha-chain (CD25) regulate the activation of CD4 and CD8 autoreactive T-cells by suppressing their proliferation and effector function. The aim of this study is to: (1) measure the percentage of CD4(+)CD25(+) T-cells (T-regs) in patients with autoimmune liver disease at presentation and during remission, (2) correlate their frequency with disease activity, (3) determine their ability to expand and (4) to inhibit interferon-gamma (IFNgamma) production by CD4(+)CD25- T-cells. METHODS: 41 patients were studied. Percentage of T-regs was determined on peripheral blood mononuclear cells (PBMCs) by triple-colour flow cytometry; their ability to expand by exposing PBMCs to a T-cell expander (CD3/CD28 Dynabeads); their immunoregulatory function by measuring their ability to suppress IFNgamma production by CD4(+)CD25(-) T-cells. RESULTS: T-regs were significantly less in patients than in controls, and at diagnosis than during remission. Their percentage was inversely correlated with titres of anti-liver kidney microsomal and soluble liver antigen autoantibodies. T-regs ability to expand was significantly lower in patients than in controls, but that to suppress IFNgamma production by CD4(+)CD25(-) T-cells was maintained. CONCLUSIONS: Decreased T-regs numbers and ability to expand may favour the emergence of liver-targeted autoimmunity, despite preserved suppressor function. Treatment should aim at increasing T-regs number.

Autoantibodies↗
PubMed2004

Microbial mimics are major targets of crossreactivity with human pyruvate dehydrogenase in primary biliary cirrhosis.

BACKGROUND/AIMS: Previous studies on patients with primary biliary cirrhosis (PBC) have shown extensive cross-reactivity between the dominant B- and T-cell epitopes of human pyruvate dehydrogenase complex-E2 (PDC-E2), and microbial mimics. Such observations have suggested microbial infection as having a role in the induction of anti-mitochondrial antibodies, through a mechanism of molecular mimicry. However the biological significance of these cross-reactivities is questionable, because PDC-E2 is so highly conserved among various species. METHODS: Interrogating protein databases, ten non-PDC-E2 microbial sequences with high degree of similarity to PDC-E2(212-226) were found in Escherichia coli (6), Helicobacter pylori, Pseudomonas aeruginosa, Cytomegalovirus, and Haemophilus influenzae. We report on a study testing reactivity and competitive cross-reactivity against these respective peptides, and in some cases the parent protein, using sera from 55 patients with PBC, compared to reactivity of 190 pathological and 28 healthy controls. RESULTS: Cross-reactivity to E. coli mimics was commonly seen in PBC, and in a subset of pathological controls except where there was no evidence of urinary tract infection and correlated with anti-mitochondrial reactivity. CONCLUSIONS: E. coli/PDC-E2 cross-reactive immunity characterizes primary biliary cirrhosis; the large number of E. coli immunogenic mimics may account for the dominance of the major PDC-E2 autoepitope.

Adult↗
PubMed2004

[Frequent genetic deletion of detoxifying enzyme GSTM1 and GSTT1 genes in nasopharyngeal carcinoma patients in Guangxi Province, China].

OBJECTIVE: To study the genetic susceptibility to chemical carcinogens of nasopharyngeal carcinoma (NPC) patients in a high-risk area in Guangxi. METHODS: PCR technique was used to examine the frequency of glutathione S-transferase M1 and T1 gene deletion in a matched case-control study of 91 patients with NPC and 135 control subjects. RESULTS: The deletion frequency of control subjects was 47.4% (65/135) for GSTM1 and 40.7% (55/135) for GSTT1, whereas that of NPC patients was 61.5% (56/91) for GSTM1 and 59.3% (54/91) for GSTT1 with statistically significant difference between the patients and the controls (P < 0.05 and P < 0.01). Furthermore, the frequency of codeletion of both genes was also higher in NPC patients than the control with statistically significant difference (chi2 = 12.533, P = 0.002). CONCLUSION: In high-risk area, nasopharyngeal carcinoma patients and local residents have high frequency of GSTM1 and/or GSTT1 gene deletion. It suggests that a genetic susceptibility to putative chemical carcinogens may be responsible for NPC clustering in the high-risk area studied.

Case-Control Studies↗