Genetic factors involved in the development of Helicobacter pylori-related gastric cancer

Genetic traits for the persistence of Helicobacter pylori infection

Helicobacter pylori infection elevates the risk of gastric diseases, including peptic ulcer and gastric cancer. Persistent infection is the first step to induce H. pylori-induced multistage diseases. Although the roles of genetic traits on persistent infection have not yet been elucidated, some individuals escape from persistent infection. Possible favorable conditions for H. pylori seem to be low acid secretion, reduced innate immune responses, and easier binding to gastric epithelial cells. IL-1β and TNF-α inhibit acid secretion. The genetic polymorphisms associated with both molecules have the potential to be the genetic traits underlying persistent infection. Functional polymorphisms associated with innate immune responses could also be involved with the genetic traits, but no polymorphisms with consistent associations have been identified so far. The polymorphisms associated with molecules for adhesion to epithelial cells are candidates of genetic traits, but more research is needed.

No association between AICDA 7888 C/T polymorphism, Helicobacter pylori seropositivity, and the risk of atrophic gastritis and gastric cancer in Japanese

BACKGROUND

The aberrant expression of activation-induced cytidine deaminase (AICDA) was reportedly induced in gastric epithelial cells infected with cytotoxin-associated gene A (cagA)-positive Helicobacter pylori, resulting in the accumulation of alterations in the TP53 tumor suppressor gene in gastric cells. We investigated the association of the AICDA 7888 C/T polymorphism with H. pylori infection and the risk of gastric cancer and atrophic gastritis in Japanese subjects.

METHODS

The study subjects were 583 histologically diagnosed gastric cancer patients (cases) and 1637 age- and sex-frequency-matched control outpatients, who visited Aichi Cancer Center Hospital from the years 2001 to 2005. In the controls, serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and atrophic gastritis, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.

RESULTS

H. pylori seropositivity in the controls was not significantly associated with the AICDA 7888 C/T genotypes. Among the H. pylori seropositive control subjects, the age and sex-adjusted ORs of atrophic gastritis were not statistically significant: 0.84 (95% CI, 0.62-1.13) for C/T, 0.82 (95% CI, 0.56-1.21) for T/T, and 0.83 (95% CI, 0.63-1.11) for C/T+T/T, relative to the C/C genotype. The age- and sex-adjusted ORs of gastric cancer relative to atrophic gastritis were also not statistically significant, at 1.17 (95% CI 0.89-1.54), 1.21 (95% CI, 0.85-1.71), and 1.18 (95% CI, 0.91-1.53), respectively. The OR of gastric cancer cases compared with the whole cohort of control subjects was also not significant.

CONCLUSION

The hypothetical association of the AICDA 7888 C/T polymorphism with the risk of gastric cancer or gastric atrophy was not shown in this study.

Infection of less virulent Helicobacter pylori strains in asymptomatic healthy individuals in Thailand as a potential contributing factor to the Asian enigma

In Thailand, gastric cancer incidence is considerably low despite the high prevalence of Helicobacter pylori infection. We investigated the prevalence of H. pylori infection and the genotypes of cagA by using 179 stool specimens obtained from asymptomatic Thai individuals. In this study, the prevalence of H. pylori infection was 43.6%, and the detection rate of cagA-positive strains was 43.5%. In addition, the proportion of the highly virulent East-Asian type of cagA was 7.2%. These results indicate that the low prevalence of cagA-positive H. pylori strain as well as the low prevalence of East-Asian genotype cagA-positive strains may contribute to the low gastric cancer incidence.

Genetic factors associated with intestinal metaplasia in a high risk Singapore-Chinese population: a cohort study

Background

Intestinal metaplasia (IM) is an important precursor lesion in the development of gastric cancer (GC). The aim of this study was to investigate genetic factors previously linked to GC risk for their possible association with IM. A total of 18 polymorphisms in 14 candidate genes were evaluated in a Singapore-Chinese population at high risk of developing GC.

Methods

Genotype frequencies were compared between individuals presenting with (n = 128) or without (n = 246) IM by both univariate and multivariate analysis.

Results

Carriers of the NQO1 609 T allele showed an association with IM in individuals who were seropositive for Helicobacter pylori (HP+; OR = 2.61, 95%CI: 1.18-5.80, P = .018). The IL-10 819 C allele was also associated with IM in HP+ individuals (OR = 2.32, 95%CI: 1.21-4.43, P = 0.011), while the PTPN11 A allele was associated with IM in HP- individuals (OR = 2.51, 95%CI: 1.16-5.40, P = 0.019), but showed an inverse association in HP+ subjects (OR = 0.46, 95%CI: 0.21-0.99, P = 0.048).

Conclusion

Polymorphisms in NQO1, IL-10 and PTPN11, in combination with HP status, could be used to identify individuals who are more likely to develop IM and therefore GC.

Response of gastric epithelial progenitors to Helicobacter pylori Isolates obtained from Swedish patients with chronic atrophic gastritis

Helicobacter pylori infection is associated with gastric adenocarcinoma in some humans, especially those that develop an antecedent condition, chronic atrophic gastritis (ChAG). Gastric epithelial progenitors (GEPs) in transgenic gnotobiotic mice with a ChAG-like phenotype harbor intracellular collections of H. pylori. To characterize H. pylori adaptations to ChAG, we sequenced the genomes of 24 isolates obtained from 6 individuals, each sampled over a 4-year interval, as they did or did not progress from normal gastric histology to ChAG and/or adenocarcinoma. H. pylori populations within study participants were largely clonal and remarkably stable regardless of disease state. GeneChip studies of the responses of a cultured mouse gastric stem cell-like line (mGEPs) to infection with sequenced strains yielded a 695-member dataset of transcripts that are (i) differentially expressed after infection with ChAG-associated isolates, but not with a “normal” or a heat-killed ChAG isolate, and (ii) enriched in genes and gene functions associated with tumorigenesis in general and gastric carcinogenesis in specific cases. Transcriptional profiling of a ChAG strain during mGEP infection disclosed a set of responses, including up-regulation of hopZ, an adhesin belonging to a family of outer membrane proteins. Expression profiles of wild-type and ΔhopZ strains revealed a number of pH-regulated genes modulated by HopZ, including hopP, which binds sialylated glycans produced by GEPs in vivo. Genetic inactivation of hopZ produced a fitness defect in the stomachs of gnotobiotic transgenic mice but not in wild-type littermates. This study illustrates an approach for identifying GEP responses specific to ChAG-associated H. Pylori strains and bacterial genes important for survival in a model of the ChAG gastric ecosystem.

The role of TNF genetic variants and the interaction with cigarette smoking for gastric cancer risk: a nested case-control study

BACKGROUND

The aim of this study was to investigate the role of TNF genetic variants and the combined effect between TNF gene and cigarette smoking in the development of gastric cancer in the Korean population.

METHODS

We selected 84 incident gastric cancer cases and 336 matched controls nested within the Korean Multi-Center Cancer Cohort. Six SNPs on the TNF gene, TNF-alpha-238 G/A, -308 G/A, -857 C/T, -863 C/A, -1031 T/C, and TNF-beta 252 A/G were genotyped. The ORs (95% CIs) were calculated using unconditional logistic regression model to detect each SNP and haplotype-pair effects for gastric cancer. The combined effects between the TNF gene and smoking on gastric cancer risk were also evaluated. Multi dimensionality reduction (MDR) analyses were performed to explore the potential TNF gene-gene interactions.

RESULTS

TNF-alpha-857 C/T containing the T allele was significantly associated with an increased risk of gastric cancer and a linear trend effect was observed in the additive model (OR = 1.6, 95% CI 1.0-2.5 for CT genotype; OR = 2.6, 95% CI 1.0-6.4 for TT genotype). All haplotype-pairs that contained TCT or CCC of TNF-alpha-1031 T/C, TNF-alpha-863 C/A, and TNF-alpha-857 C/T were associated with a significantly higher risk for gastric cancer only among smokers. In the MDR analysis, regardless of smoking status, TNF-alpha-857 C/T was included in the first list of SNPs with a significant main effect.

CONCLUSION

TNF-alpha-857 C/T polymorphism may play an independent role in gastric carcinogenesis and the risk for gastric cancer by TNF genetic effect is pronounced by cigarette smoking.

Associations of a PTPN11 G/A polymorphism at intron 3 with Helicobactor pylori seropositivity, gastric atrophy and gastric cancer in Japanese

Background

Previous studies have revealed the significance of Helicobacter pylori (H. pylori) infection as a risk factor of gastric cancer. Cytotoxin-associated gene A (cagA) positivity has been demonstrated to determine the clinical outcome of H. pylori infection in the presence of SHP-2 (src homology 2 domain-containing protein tyrosine phosphatase-2). This study aimed to examine the formerly reported association of G/A PTPN11 (protein-tyrosine phosphatase, nonreceptor-type 11) polymorphism (rs2301756) with gastric atrophy, as well as the association with gastric cancer in a Japanese population using a large sample size.

Methods

Study subjects were 583 histologically diagnosed patients with gastric cancer (429 males and 154 females) and age- and sex-frequency-matched 1,636 non-cancer outpatients (1,203 males and 433 females), who visited Aichi Cancer Center Hospital between 2001–2005. Serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.

Results

Among H. pylori seropositive non-cancer outpatients, the age- and sex-adjusted OR of gastric atrophy was 0.82 (95% CI 0.62–1.10, P = 0.194) for G/A, 0.84 (95% CI 0.39–1.81, P = 0.650) for A/A, and 0.83 (95% CI 0.62–1.09, P = 0.182) for G/A+A/A, relative to G/G genotype, and that of severe gastric atrophy was 0.70 (95% CI 0.47–1.04, P = 0.079), 0.56 (95% CI 0.17–1.91, P = 0.356), and 0.68 (95% CI 0.46–1.01, P = 0.057), respectively. Among H. pylori infected subjects (H. pylori seropositive subjects and seronegative subjects with gastric atrophy), the adjusted OR of severe gastric atrophy was further reduced; 0.62 (95% CI 0.42–0.90, P = 0.012) for G/A+A/A. The distribution of the genotype in patients with gastric cancer was not significantly different from that for H. pylori infected subjects without gastric atrophy.

Conclusion

Our study results revealed that those with the A/A genotype of PTPN11 rs2301756 polymorphism are at lower risk of severe gastric atrophy, but are not associated with a decreased risk of gastric cancer, which partially supported our previous finding that the polymorphism in the PTPN11 gene encoding SHP-2 was associated with the gastric atrophy risk in H. pylori infected Japanese. The biological roles of this PTPN11 polymorphism require further investigation.

Single nucleotide polymorphism of interleukin-1beta associated with Helicobacter pylori infection in immune thrombocytopenic purpura

To examine the role of genetic factors in development of immune thrombocytopenic purpura (ITP) in association with Helicobacter pylori infection, gene polymorphisms within the loci for human leukocyte antigen class II, interleukin (IL)-1beta (-511), tumor necrosis factor-beta (+252), immunoglobulin (Ig)G1 heavy chain (+643), and Igkappa light chain (+573) were determined in 164 adults with ITP and 75 healthy controls. Of these gene polymorphisms, the IL-1beta (-511) T allele was less frequently detected in H. pylori-infected than in H. pylori-uninfected (58% vs 81%, P = 0.01, odds ratio = 0.31) ITP patients diagnosed before age 50. These findings suggest that a single nucleotide polymorphism within the IL-1beta (-511) may affect susceptibility to early-onset ITP associated with H. pylori infection.

Meta-analysis of genetic polymorphisms and gastric cancer risk: variability in associations according to race

The goal of this study was to consolidate information on genetic risk factors for gastric cancer. An additional aim was to investigate the influence of race on these genetic risk associations. Relevant studies were identified from PubMed and references of retrieved articles. Meta-analysis techniques were used to summarise associations between genetic polymorphisms and gastric cancer. A total of 203 relevant studies were identified, assessing 225 polymorphisms across 95 genes. Subgroup analysis indicated that Chinese, Japanese and Korean data were consistent and could be pooled. However, 6 of 13 polymorphisms (ACE I/D, CCND1 870G>A, CDH1 -160C>A, IL1B -511C>T, IL4 -590C>T, IL10 -592A>C) displayed conflicting effects between Asian and Caucasian populations, three of which (ACE I/D, CCND1 870G>A, IL1B -511C>T) had significantly different odds ratios between the two racial groups. In total, 37 polymorphisms across 27 genes were found to be significantly associated with gastric cancer in Asians, and 12 polymorphisms across 11 genes in Caucasians. Consolidated panels of polymorphisms associated with gastric cancer risk were identified in Asians and Caucasians. The results caution against the assumption that genetic risk factors are consistent between races.

Association between chronic atrophic gastritis and serum antibodies to 15 Helicobacter pylori proteins measured by multiplex serology

Infection with Helicobacter pylori is a major risk factor for chronic atrophic gastritis (CAG), a precursor lesion of intestinal gastric cancer. The pathogenicity of the bacterium is thought to play an important role in determining the extent and severity of clinical outcome. We aimed to assess the associations between CAG and the serostatus of antibodies to 15 H. pylori proteins. The analyses were based on 534 cases with serologically defined CAG and 1,068 age-matched and sex-matched controls participating in a population-based study conducted in Saarland, Germany among 9,953 men and women ages 50 to 74 years. A newly developed H. pylori multiplex serology method was used to detect antibodies specific to 15 H. pylori antigens. Significant associations were observed between seropositivity for all 15 specific antibodies and the presence of CAG. Exclusion of severe cases, who might have lost the infection in the course of CAG progression, substantially increased the observed associations. In H. pylori-seropositive subjects, cytotoxin-associated gene A (CagA), vacuolating toxin (VacA), helicobacter cysteine-rich protein C (HcpC), and the chaperonin GroEL were identified as independent virulence factors for CAG with adjusted odds ratios (95% confidence interval) of 3.52 (2.01-6.10), 3.19 (1.44-7.05), 4.03 (1.53-10.65), and 2.65 (1.06-6.62), respectively; the simultaneous presence of all four independent virulence factors was associated with an 18-fold risk of CAG. In conclusion, HcpC and GroEL were identified as new independent virulence factors, and in combination with the established virulence factors, CagA and VacA, were strongly associated with CAG.

Functional polymorphism of NFKB1 promoter may correlate to the susceptibility of gastric cancer in aged patients

BACKGROUND

Activated nuclear factor-kappaB (NF-kappaB) is associated reportedly with the pathogenesis of numerous malignancies. This study investigated whether a common insertion (ins)/deletion (del) polymorphism (-94 ins/del ATTG) in the NFKB1 promoter is associated with susceptibility to gastric cancer and its tumor behavior.

METHODS

Blood samples from 182 gastric cancer patients and 116 controls were examined by polymerase chain reaction-based genotyping. Allelotype and genotype (polymorphism) of NFKB1 promoter in gastric cancer patients were analyzed with controls and patients' clinicopathologic factors to evaluate their association using a multivariate analytical model.

RESULTS

The mean ages of patients and controls were 65.7 +/- 12.8, and 64.9 +/- 8.8 years old, respectively. Sex ratios (male to female) were 2.7:1 and 2.2:1, respectively. Insertion allelotype, genotypes with ins/ins, as well as ins allele carrier (ins/ins+ ins/del) were significantly greater in gastric cancer patients than in controls, especially in patients >65 years old, but not in younger patients. The polymorphism did not correlate with clinicopathologic factors and patient survival.

CONCLUSION

NFKB1 could be a susceptible gene for gastric cancer and its functional polymorphism in promoter is associated with the risk of gastric cancer, particularly in aged patients.

Toll-like receptor 4 +3725 G/C polymorphism, Helicobacter pylori seropositivity, and the risk of gastric atrophy and gastric cancer in Japanese

BACKGROUND

Toll-like receptor 4 (TLR4) Asp299Gly and Thr399Ile polymorphisms were reported to be a risk factor of gastric carcinoma or its precursors in Caucasian and Indian population, but these polymorphisms are absent in Japanese. We investigated the associations of TLR4+3725 G/C polymorphism, another functional polymorphism of TLR4, with risk of gastric cancer and gastric atrophy in Japanese.

MATERIALS AND METHODS

Study subjects were 583 histologically diagnosed gastric cancer patients and age- and sex-matched 1592 control outpatients, who visited Aichi Cancer Center Hospital from 2001 to 2005. Serum anti-H. pylori IgG antibody and pepsinogens were measured to evaluate H. pylori infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.

RESULTS

Among the seropositive subjects, the age- and sex-adjusted OR of gastric atrophy was 1.17 (95%CI: 0.91-1.50) for G/C, 1.20 (95%CI: 0.76-1.89) for C/C, and 1.18 (95%CI: 0.93-1.49) for G/C+C/C relative to G/G genotype. The age- and sex-adjusted OR of severe gastric atrophy among H. pylori seropositive subjects was 1.43 (95%CI: 0.99-2.06) for G/C, 1.47 (95%CI: 0.76-2.88) for C/C, and 1.43 (95%CI: 1.01-2.04) for G/C+C/C. The OR of gastric cancer compared with gastric atrophy controls was not statistically significant.

CONCLUSION

Our study found that TLR4+3725 G/C polymorphism was a risk factor of severe gastric atrophy in H. pylori seropositive Japanese. Our results underscored the significance of the variations in host innate immunity due to TLR4 polymorphism as genetic predispositions to gastric precancerous lesions in Eastern Asian populations with the same backgrounds.

Meta-analysis: tumour invasion-related genetic polymorphisms and gastric cancer susceptibility

BACKGROUND

Host genetic susceptibility has been suggested as one of the most important possible explanations for interindividual difference in gastric cancer (GC) risk.

AIM

To evaluate the impact of tumour invasion-related gene polymorphisms, which may be involved in a variety of processes during GC development, such as cell adhesion and angiogenesis, on the risk of GC.

METHODS

We reviewed published studies on tumour invasion-related gene polymorphisms and GC susceptibility until 31 March 2008, and then quantitatively summarized associations of the most widely-studied polymorphism, CDH1 -160C>A, with GC using meta-analysis.

RESULTS

Twenty-seven eligible studies were included in this review. Fourteen polymorphisms significantly related to GC in at least one study were identified. For several polymorphisms, heterogeneous results were observed and associations in opposite directions were seen among Asian and Caucasian populations. In meta-analysis, CDH1 -160C>A showed an inverse association with GC among Asians (OR, 0.76; 95% CI, 0.55-1.05) and a positive association among Caucasians (OR, 1.40; 95% CI, 0.95-2.04).

CONCLUSIONS

This review suggests that genetic polymorphisms in tumour invasion could be candidate biomarkers of GC risk. However, differences between populations and stages of cancer need to be taken into account and may explain some of the inconsistencies found in previous studies.

Translational research in gastric malignancy

This article discusses recent advances in gastric cancer research that have improved treatment and outcomes of gastric malignancy, or have the potential to do so. The significance of Helicobacter pylori infection and eradication, immunology, host genetics, proto-oncogenes, and epigenetic alterations in gastric cancer are discussed. Abnormal signaling through growth factor pathways (tyrosine kinases and gastrointestinal peptides) presents ample opportunities for therapeutic intervention that are currently being tested in clinical trials. Drugs targeting abnormal epigenetic changes, such as DNA hypermethylation and histone deacetylation, are also on the horizon, although most of this research is still in the preclinical phase. The potential prognostic implications of genetics and immunology in gastric cancer prognosis are also reviewed.

Increased risk of gastric cancer in Japanese subjects is associated with microsatellite polymorphisms in the heme oxygenase-1 and the inducible nitric oxide synthase gene promoters

Microsatellite polymorphism in the promoter region of the heme oxygenase-1 (HO-1) gene was analyzed jointly with that of the inducible nitric oxide synthase (iNOS) gene among Japanese subjects (control and gastric cancer patients). A higher promoter activity genotype of the HO-1 gene was associated with increased risk for gastric cancer in women. Gastric cancer risk was notably increased in subjects carrying a higher promoter activity genotype for both HO-1 and iNOS compared to those with a lower promoter activity genotype for both genes. Our data suggest that genetic polymorphisms of HO-1 and iNOS modulate individual susceptibility to gastric cancer risk.

Frequency of Helicobacter pylori and CagA antibody in patients with gastric neoplasms and controls: the Indian enigma

BACKGROUND

Despite association between H. pylori and gastric neoplasm (GN) from the developed world, studies from India, where infection is more common and acquired early, are scant and contradictory.

METHODS

Two hundred and seventy-nine patients with GN from two northern and one eastern Indian centers during the period 1997-2005, 101 non-ulcer dyspepsia (NUD), and 355 healthy volunteers (HV) were evaluated for H. pylori [rapid urease test (RUT), histology and anti-H. pylori, and CagA IgG serology].

RESULTS

Patients with GN [263 gastric carcinoma and 16 (6%) primary gastric lymphoma, 208 male] were older than HV (n = 355, 188 male) and NUD (n = 101, 54 male) patients (53 +/- 12 versus 44 +/- 17 and 43 +/- 13 years, respectively; P < 0.001). Eastern Indian patients with GN (n = 145) were younger than those from northern India (n = 134; 52 +/- 12 versus 55 +/- 12 years; P < 0.007, t-test). In GN and NUD patients H. pylori positivity by RUT [86/225 (38%) versus 46/101 (46%)], anti-H. pylori IgG [154/198 (78%) versus 85/101 (84%)], and histology [136/213 (64%) versus 55/101 (55%)] were comparable (chi(2)-test). Serum IgG anti-H. pylori antibody was more common among HV than among GN patients [300/355 (85%) versus 154/198 (78%); P = 0.04, chi(2)-test]. Intestinal metaplasia was more common in GN than in NUD patients [101/252 (40%) versus 2/98 (2%), P < 0.000, chi(2)-test]. CagAIgG was more common in GN than in NUD patients [124/163 (76%) versus 64/101 (63%)] but comparable to that in HV patients [87/98 (89%), P = NS].

CONCLUSION

Frequency of H. pylori as detected using endoscopy and serology-based tests is not higher among patients with GN as compared with controls in India.

Cytogenetic and molecular aspects of gastric cancer: clinical implications

Gastric cancer is of major importance world-wide being the second most common cause of cancer-related death in the world. According to Lauren's histological classification gastric cancer is divided in two groups, the better differentiated intestinal carcinomas and the poorly differentiated diffuse-type cancers. The genetic changes underlying the initiation and progression of gastric cancer are not well defined. Gastric carcinogenesis is a multistep process involving a number of genetic and epigenetic factors. Although it has been proposed that different genetic pathways exist for differentiated and undifferentiated carcinomas, the two histological subtypes of gastric cancer share some common genetic alterations. Currently, tumor histology and pathologic stage are the major prognostic variables used in the clinical practice for gastric cancer patients. However, it is known that tumors with similar morphology may differ in biological aggressiveness, prognosis and response to treatment. Molecular genetic analysis of gastric cancer revealed a number of associations of certain genetic changes with pathological features, tumor biological behavior and prognosis of gastric cancer patients, suggesting that these genetic abnormalities might play an important role in gastric tumorigenesis. Increasing evidence suggests that the molecular genetic changes could be helpful in the clinical setting, contributing to prognosis and management of patients. Regarding epigenetic events in gastric tumorigenesis, a number of methylating markers have been proposed for risk assessment, prognostic evaluation and as therapeutic targets. However, further research is required in order to systematically investigate the genetic changes in gastric cancer estimating also their usefulness in the clinical practice. A good understanding of the genetic changes underlying gastric carcinogenesis may provide new perspectives for prognosis and screening of high risk individuals. Some of the genetic alterations could definitely improve tumor classification and management of gastric cancer patients. Also, based on molecular data identified in gastric cancer novel therapeutics might help to improve the treatment of this disease.

Expression of the full-length telomerase reverse transcriptase (hTERT) transcript in both malignant and normal gastric tissues

Activation of telomerase by the induction of a full-length telomerase reverse transcriptase (hTERT) transcript is a critical step during cellular immortalization and malignant transformation. Telomerase activity or hTERT expression has thus served as diagnostic and/or prognostic markers in different types of human malignancies. In the present study, we investigated the expression of the telomerase components hTERT and telomerase RNA template (hTER) in normal and malignant gastric tissues derived from 37 patients with gastric cancers. Overall hTERT mRNA was detectable in 33/37 (90%) of tumour specimens and 23/37 (62%) of the corresponding normal gastric tissues. Twenty-five of thirty-seven tumours (71%) expressed the full-length hTERT mRNA, and unexpectedly, this full-length transcript was found in 16 of 37 (43%) normal gastric tissues. Immunohistochemical analyses demonstrated a positive hTERT staining in small fractions of normal epithelial cells and in most gastric cancer cells. A close correlation between the presence of a full-length hTERT transcript and the c-MYC oncogene expression was observed in both normal and cancerous gastric specimens. Moreover, the full-length hTERT expression was positively associated with the tumour size in these patients. Similar levels of hTER expression were expressed in tumour and their corresponding normal tissues. The finding that the full-length hTERT transcript was present in both normal and malignant gastric tissues will preclude its use as a gastric cancer marker. Nevertheless, full-length hTERT mRNA expression may indicate a progressive gastric cancer, and its presence in normal gastric mucosa may have an impact on the anti-telomerase strategy for cancer therapeutic purpose.