Medium and large alleles of the PGC gene are risk factors for gastric cancer.

BACKGROUND: A 100-bp insertion/deletion polymorphism in the pepsinogen C gene has been associated with the risk of gastric cancer (GC). OBJECTIVE: We analyzed the relationships of the 100-bp insertion/deletion polymorphism with GC, atrophic gastritis (AG), and intestinal metaplasia (IM) in the Mexican general population (MGP). METHODS: We studied the genomic DNA of subjects with GC n = 80, AG and IM n = 60, controls n = 110, and the MGP n = 97. PGC gene insertion/deletion polymorphism was identified by means of PCR, capillary electrophoresis and GeneScan software. RESULTS: Different allele sizes of PGC polymorphism were observed in the studied groups, from 266 bp to 499 bp, which were grouped for the analysis as short alleles of 266-399 bp, medium alleles of 400-433 bp and large alleles of 434-499 bp. Carriers of one or two medium alleles, had an increased risk of GC, with OR of 1.99 (CI95% 1.08-3.67 p = 0.026) compared to homozygotes (no medium/no medium). CONCLUSIONS: Previous studies have related PGC short alleles to risk for or protection against GC depending on the ethnic origin of the population. In our study, medium alleles were related to risk for GC. Further studies are required to establish the importance of this polymorphism in the origin of gastric neoplasia.

Aspectos histológicos, genéticos y moleculares de las lesiones preneoplásicas de la mucosa gástrica / Histological, genetic and molecular aspects of preneoplastic lesions of the gastric mucosa

Siendo el cáncer gástrico la 3ª causa de muerte por cáncer en Chile, y existiendo estrategias de tamizaje consistentes en pesquisa de lesiones preneoplásicas de la mucosa gástrica, es relevante conocer los aspectos genéticos y moleculares que puedan ser aplicados, en la optimización de dichas estrategias a grupos de mayor riesgo. El objetivo de este manuscrito fue revisar la evidencia actual en los aspectos señalados, y de la inmunohistoquímica de 4 marcadores (p53, CDX2, MUC2 y S100A9) en la mucosa gástrica normal y en las lesiones preneoplásicas de la misma.

SUMMARY: Since gastric cancer is the 3rd leading cause of death from cancer in Chile, and there are screening strategies consisting of screening for preneoplastic lesions of the gastric mucosa, it is important to know certain genetic and molecular aspects that can be applied in optimizing these strategies for higher risk groups. The aim of this manuscript was to review the current evidence on the aforementioned aspects, and on the immunohistochemistry of 4 markers (p53, CDX2, MUC2 and S100A9) in normal gastric mucosa and in its preneoplastic lesions.

Prevalence of Gastric Preneoplastic Lesions in First-Degree Relatives of Patients with Gastric Cancer: a Cross-Sectional Study.

PURPOSE: Worldwide, gastric cancer (GC) is the 5th cancer with the highest incidence and the 4th in mortality. To reduce it, one strategy is to diagnose preneoplastic lesions (PNL): atrophic gastritis (AG), intestinal metaplasia (IM), and dysplasia (DYS); to form risk groups on which to focus surveillance efforts as are first-degree relatives (FDR). The aim of this study was to determine prevalence of gastric PNL in FDR of patients with GC, and to study association with sex, age, and Helicobacter pylorii (Hp) infection. METHODS: Cross-sectional study. One hundred and ten FDR, aged between 50 and 65 years, 54.5 female, obtained through convenience sampling, were studied. Biodemographic data survey and upper gastrointestinal endoscopy with histological study were applied according to Sidney protocol, and focal lesions found. Diagnosis of these lesions and condition of mucosa was carried out by applying OLGA and OLGIM systems. Descriptive statistics, estimation of prevalence, odds ratio (OR), and 95% confidence intervals (95CI) were calculated. RESULTS: Median age of study group was 56.5 years. Prevalence of PNL, AG, IM, and DYS were 86.4%, 82.7%, 54.5%, and 12.7% respectively. Advanced stages of OLGA and OLGIM were verified in 18.0% and 16.3% respectively. No association with sex, age, and Hp infection were found ([OR 3.10; 95CI 1.0; 9.64]; [OR 0.74; 95CI 0.26; 2.14]; [OR 0.58; 95CI 0.12; 2.77]) respectively. CONCLUSION: FDR of patients with GC have a high prevalence of PNL, which makes them a risk group in which endoscopic surveillance should be applied.

Morfología y repercusiones diagnóstico-terapéuticas de las lesiones preneoplásicas gástricas / Morphology and diagnostic determinants of gastric precancerous conditions

El carcinoma gástrico (CG) de tipo intestinal se origina en un epitelio displásico, que a su vez se desarrolla en medio de una atrofia gástrica (AG) y metaplasia intestinal (MI). La infección por Helicobacter pylori (HP) es la causa más frecuente de AG, causando una pangastritis atrófica multifocal. Entre otras condiciones que producen inflamación crónica de la mucosa gástrica se encuentran también la gastritis autoinmune y la anemia perniciosa. El marco conceptual sobre el cual descansa gran parte de la investigación actual y nuestra comprensión de los cambios que ocurren en la mucosa gástrica se debe a la denominada "cascada de Correa"; quien planteó que la mucosa gástrica crónicamente inflamada, da paso a la AG, que va adquiriendo focos de MI y en dicho epitelio se desarrollará finalmente una displasia (DIS). Se ha acuñado el término lesiones preneoplásicas gástricas (LPG), para referirse a: AG, MI y DIS.Después de la erradicación de HP, se ha demostrado una reducción general de la incidencia de CG; efecto que no es tan claro, cuando la pangastritis por HP ha evolucionado a AG extensa. De tal modo que el efecto de la erradicación de HP medido a través de EC, ha sido poco consistente. La AG grave diagnosticada por histología representa la condición de mayor riesgo. Por otra parte, la MI puede ser de tipo intestinal (delgado-entérica ó incompleta) y la colónica (colónica ó completa) considerándose a esta última, como la variedad de peor pronóstico. El diagnóstico histológico de este tipo de lesiones determina que quien las padece, debe someterse a vigilancia endoscópica. El objetivo de este manuscrito fue resumir la evidencia existente respecto de las LPG, en términos de su caracterización morfológica y sus repercusiones diagnóstico-terapéuticas (significado patológico, graduación del riesgo, vigilancia recomendada; y factores de riesgo).

Gastric carcinoma (GC) of intestinal type, originates from a dysplastic epithelium, which in turn develops in the midst of gastric atrophy (GA) and intestinal metaplasia (IM). Helicobacter pylori (HP) infection is the most frequent cause of GA, causing a multifocal atrophic pangastritis. Among other conditions that produce chronic inflammation of gastric mucosa are also autoimmune gastritis and pernicious anemia. The conceptual framework on which much of current research rests and our understanding of the changes that occur in the gastric mucosa is due to the so-called "Correa waterfall"; who stated that gastric mucosa chronically inflamed, gives way to the GA, which is acquiring foci of IM and in said epithelium a dysplasia (DIS) will eventually develop. The term precancerous conditions (PCC) of the gastric mucosa have been coined to refer to: GA, IM and DIS. After HP eradication, a general reduction in the incidence of GC has been demonstrated; effect that is not so clear, when pangastritis by HP has evolved to extensive GA. Thus, the effect of HP eradication measured through clinical trials has been inconsistent. Severe GA diagnosed represents the highest risk condition. On the other hand, IM can be enteric (grade I), enterocolic (grade II) or colonic (grade III); considering IM III as the variety with the worst prognosis. Histological diagnosis of gastric PCC, determines that the one who suffers them, must undergo endoscopic surveillance. The aim of this manuscript was to update morphological aspects and diagnostic-therapeutic scope of gastric PCC.