Secondary prevention of gastric cancer

Assessment of Gastritis and Gastric Cancer Risk in the Chilean Population Using the OLGA System

Gastric cancer (GC) is the first cancer-related cause of death in Chile; however, no plan for GC early detection has been implemented in this country. The OLGA system characterizes gastritis from stages 0 to IV according to the risk of developing GC based on H. pylori infection, atrophy, metaplasia and GC. In this study, the performance of the OLGA system was evaluated in 485 Chilean patients receiving routine endoscopy to improve the detection of early GC or preneoplastic lesions. The results showed that OLGA scores, atrophy, metaplasia and GC increased significantly with age (p < 0.001). Conversely, H. pylori infection was higher in younger groups (p < 0.05). All gastric lesions were more frequent in men than women. The majority of patients with atrophy also had metaplasia (99%, p < 0.0001). Patients with H. pylori infection had more gastric atrophy and metaplasia than those without infection (p < 0.05). Of the 485 patients, 21 (4.3%) had GC, being 2.3 times more frequent among men than women and about 2/3 (14) were in OLGA stage ≥2. In addition, 19 (90%) GC patients had atrophy and 18 (85%) had metaplasia (p < 0.001). In conclusion, the OLGA system facilitated the evaluation of GC precursor lesions particularly in patients with an OLGA score > 2 between 45 and 56 years old, because this group showed atrophy and intestinal metaplasia more frequently. Therefore, biennial endoscopic surveillance of patients with an OLGA >2 can be an important health policy in Chile for diagnosing GC in its early stages and reducing mortality over the next two decades.

A Serological Biopsy Using Five Stomach-Specific Circulating Biomarkers for Gastric Cancer Risk Assessment: A Multi-Phase Study

OBJECTIVES

We aimed to assess a serological biopsy using five stomach-specific circulating biomarkers-pepsinogen I (PGI), PGII, PGI/II ratio, anti-Helicobacter pylori (H. pylori) antibody, and gastrin-17 (G-17)-for identifying high-risk individuals and predicting risk of developing gastric cancer (GC).

METHODS

Among 12,112 participants with prospective follow-up from an ongoing population-based screening program using both serology and gastroscopy in China, we conducted a multi-phase study involving a cross-sectional analysis, a follow-up analysis, and an integrative risk prediction modeling analysis.

RESULTS

In the cross-sectional analysis, the five biomarkers (especially PGII, the PGI/II ratio, and H. pylori sero-positivity) were associated with the presence of precancerous gastric lesions or GC at enrollment. In the follow-up analysis, low PGI levels and PGI/II ratios were associated with higher risk of developing GC, and both low (<0.5 pmol/l) and high (>4.7 pmol/l) G-17 levels were associated with higher risk of developing GC, suggesting a J-shaped association. In the risk prediction modeling analysis, the five biomarkers combined yielded a C statistic of 0.803 (95% confidence interval (CI)=0.789-0.816) and improved prediction beyond traditional risk factors (C statistic from 0.580 to 0.811, P<0.001) for identifying precancerous lesions at enrollment, and higher serological biopsy scores based on the five biomarkers at enrollment were associated with higher risk of developing GC during follow-up (P for trend <0.001).

CONCLUSIONS

A serological biopsy composed of the five stomach-specific circulating biomarkers could be used to identify high-risk individuals for further diagnostic gastroscopy, and to stratify individuals' risk of developing GC and thus to guide targeted screening and precision prevention.

A comprehensive evaluation of fasting serum gastrin-17 as a predictor of diseased stomach in Chinese population

BACKGROUND AND AIM

Fasting serum gastrin-17 (FsG17) is considered as a noninvasive biomarker reflecting the structure and functional status of gastric mucosa, but its clinical utility remains unclear. This study aimed to evaluate FsG17 comprehensively: establish the ranges and cut-off points of FsG17 levels in different gastric diseases, identify their influencing factors, and investigate the accuracy of FsG17 for identifying diseased stomach.

METHODS

The study included 4064 participants from Northern China between 2008 and 2013. FsG17 and serum Helicobacter pylori IgG antibody levels were measured by enzyme-linked immunosorbent assay. Diagnostic accuracy was assessed by receiver operator characteristic curves. Multivariate logistic regression analysis was performed to determine the best predictors of gastric histopathological conditions.

RESULTS

Median FsG17 levels in healthy, non-atrophic, atrophic, and cancerous stomachs were 1.8, 4.0, 3.8, and 6.1 pmol/l, respectively. Age, smoking status, alcohol consumption, H. pylori infection, and predominant lesion site were factors that affected FsG17 levels. The optimal cut-off values for FsG17 were 3.0 pmol/l (sensitivity of 59.3% and specificity of 67.3%) for discriminating between healthy stomach and diseased stomach and 10.7 pmol/l (sensitivity of 37% and specificity of 83.7%) for discriminating between cancerous stomach and cancer-free stomach; the screening accuracy was higher (sensitivity of 50.0% and specificity of 83.0%) for gastric cancer in the corpus. Multivariate analysis showed that FsG17, gender, age, and H. pylori infection were independent predictors of cancerous stomach.

CONCLUSION

With the progression from health stomach to malignancy, FsG17 levels significantly increased and were influenced by other factors. FsG17 combined with age, gender, and H. pylori infection could distinguish between cancerous stomach and cancer-free stomach. The results will enhance our understanding of the potential clinical utility of FsG17.

Temporal changes in serum biomarkers and risk for progression of gastric precancerous lesions: a longitudinal study

Effectively managing precancerous lesions is crucial to reducing the gastric cancer (GC) burden. We evaluated associations of temporal changes in multiple serological markers (pepsinogen I [PGI], PGII, PGI/II ratio, gastrin-17 and anti-Helicobacter pylori IgG) with risk for progression of gastric precancerous lesions. From 1997 to 2011, repeated esophagogastroduodenoscopies with gastric mucosal biopsies and blood sample collections were conducted on 2,039 participants (5,070 person-visits) in the Zhuanghe Gastric Diseases Screening Program, Liaoning, China. Serum biomarkers were measured using ELISA, and gastric biopsies were evaluated using standardized histologic criteria. Odds ratios (OR) and 95% confidence intervals (CI) were estimated using generalized estimating equations for correlated binary outcomes. The ORs for progression of gastric conditions comparing those whose serum PGI, PGII, and anti-H. pylori IgG levels increased ≥ 50% relative to those whose decreased ≥ 50% were, respectively 1.67 (CI, 1.22-2.28), 1.80 (CI, 1.40-2.33) and 1.93 (CI, 1.48-2.52). The OR for those whose PGI/II ratio decreased ≥ 50% relative to those whose increased ≥ 50% was 1.40 (CI, 1.08-1.81), and for those whose PGII and anti-H. pylori IgG levels both increased ≥ 50% relative to those whose levels both decreased ≥ 50% the OR was 3.18 (CI, 2.05-4.93). Changes in gastrin-17 were not statistically significantly associated with progression. These findings suggest that temporal changes in serum PGI, PGII, PGI/II ratio, and anti-H. pylori IgG levels (especially PGII and anti-H. pylori IgG combined) may be useful for assessing and managing risk for progression of gastric precancerous lesions.

A polysaccharide from Salvia miltiorrhiza Bunge improves immune function in gastric cancer rats

A neutral polysaccharide fraction (SMPA) prepared from the roots of Salvia miltiorrhiza by DEAE-cellulose and Sephadex G-100 chromatography was tested for its immune enhancing function in N-methyl-N'-nitro-nitrosoguanidine (MNNG)-induced gastric cancer rats by intragastric administration. SMPA (200mg/kg) treatment not only increased the body weight, but also improved the immune organ indices. Furthermore, studies of various immunological activities in gastric cancer rats revealed that SMPA significantly stimulated splenocyte proliferation, promoted anti-inflammatory cytokines (IL-2, IL-4 and IL-10) production, inhibited pro-inflammatory cytokine (IL-6 and TNF-α) secretion, augmented the killing activity of natural killer (NK) cells and cytotoxic T lymphocytes (CTL), and increased phagocytotic function of macrophages in gastric cancer rats. In addition, SMPA administration evidently elevated total intracellular granzyme-B and IFN-γ levels produced by splenocytes in gastric cancer rats. Taken together, these results suggested that SMPA could act as an effective immunomodulator and might be explored as a potential supplemental source for gastric cancer therapy.

Panax ginseng polysaccharide induces apoptosis by targeting Twist/AKR1C2/NF-1 pathway in human gastric cancer

In the present study, we isolated and screened an antitumor polysaccharide (PGP2a) from the roots of Panax ginseng. Chemical composition analysis indicated PGP2a was an acidic protein-polysaccharide. The average molecular weight was estimated to be 3.2 × 10(4)Da. According to gas chromatography (GC) result, PGP2a consisted of galactose, arabinose, glucose and galacturonic acid in the molar ratio of 3.7:1.6:0.5:5.4, respectively. MTT assay showed that PGP2a had a potent inhibitory effect on the growth of HGC-27 cells in a dose-dependent fashion. Furthermore, the number of HGC-27 cells arrested in G2/M phase, and the percentage of apoptotic cells were increased in response to PGP2a treatment along with concentration increasing. Moreover, western blotting analysis showed that protein expressions of Twist and AKR1C2 were suppressed by PGP2a, whereas an increase of NF1 was observed at protein level. Taken together, these findings suggested that PGP2a could be developed as a novel antitumor agent acting on Twist related gene for human gastric cancer therapy.

The association between precancerous gastric lesions and serum pepsinogens, serum gastrin, vascular endothelial growth factor, serum interleukin-1 Beta, serum toll-like receptor-4 levels and Helicobacter pylori Cag A status

BACKGROUND AND OBJECTIVE

The aim of this study was to investigate the association between serum pepsinogens, serum gastrin, serum vascular endothelial growth factor, serum interleukin-1 Beta, serum toll-like receptor-4 levels and Helicobacter pylori Cag A status in patients with various gastric precancerous lesions.

METHODS

One hundred and sixty two consecutive patients with various gastric lesions [38 (23.5%) H. pylori positive chronic non-atrophic gastritis, 45 (27.8%) autoimmune gastritis, 42 intestinal metaplasia and 37 dysplasia] were enrolled into the study. Serum pepsinogen I and II, gastrin 17, vascular endothelial growth factor, interleukin-1 Beta, toll-like receptor-4 levels, H. pylori Cag A status were evaluated.

RESULTS

H. pylori was positive in 98 (60.5%) patients and 38 of these patients were Cag A positive. Serum pepsinogen level was significantly lower in patients with autoimmune atrophic gastritis compared to the patients with non-atrophic chronic gastritis (p<0.001), intestinal metaplasia (P<0.001) and dysplasia (P=0.002). Mean serum gastrin was 1209.6±268.48 pg/mL in patients with autoimmune atrophic gastritis and 234.95±184.018 pg/mL in patients with chronic non-atrophic gastritis. Mean toll-like receptor-4 level was 0.56±0.098 ng/mL in patient with dysplasia, and this value was higher compared to patients with chronic non-atrophic gastritis (P=0.007), autoimmune atrophic gastritis (P=0.003) and intestinal metaplasia (P=0.006). Interleukin-1 Beta level was significantly lower in patients with dysplasia compared to patients with chronic non-atrophic gastritis (P=0.034).

CONCLUSIONS

Serum pepsinogens, serum gastrin and H. pylori Cag A status are important tests in detecting gastric precancerous lesions. However, toll-like receptor-4 may be a sensitive test to differentiate the patients with dysplasia from the other precancerous gastric lesions. Non-invasive tests are sensitive in the diagnosis of gastric precancerous lesions.

Precancerous lesions in the stomach: from biology to clinical patient management

Gastric cancer is the final step in a multi-stage cascade triggered by long-standing inflammatory conditions (particularly Helicobacter pylori infection) resulting in atrophic gastritis and intestinal metaplasia: these lesions represent the cancerization field in which (intestinal-type) gastric cancer develops. Intraepithelial neoplasia is consistently recognized as the phenotypic bridge between atrophic/metaplastic lesions and invasive cancer. This paper addresses the epidemiology, pathology, molecular profiling, and clinical management of advanced precancerous gastric lesions.

Gastritis: the histology report

Gastritis is defined as inflammation of the gastric mucosa. In histological terms, it is distinguishable into two main categories, i.e. non-atrophic and atrophic. In the gastric mucosa, atrophy is defined as the loss of appropriate glands. There are several etiological types of gastritis, their different etiology being related to different clinical manifestations and pathological features. Atrophic gastritis (resulting mainly from long-standing Helicobacter pylori infection) is a major risk factor for the onset of (intestinal type) gastric cancer. The extent and site of the atrophic changes correlate significantly with the cancer risk. The current format for histology reporting in cases of gastritis fails to establish an immediate link between gastritis phenotype and risk of malignancy. Building on current knowledge of the biology of gastritis, an international group of pathologists [Operative Link for Gastritis Assessment (OLGA)] has proposed a system for reporting gastritis in terms of its stage (the OLGA Staging System): this system places the histological phenotypes of gastritis on a scale of progressively increasing gastric cancer risk, from the lowest (Stage 0) to the highest (Stage IV). The aim of this tutorial is to provide unequivocal information on how to standardize histology reports on gastritis in diagnostic practice.

Helicobacter pylori immunoproteomics in gastric cancer and gastritis of the carcinoma phenotype

Helicobacter pylori infection is linked to the development of gastric cancer. Atrophic body gastritis is considered the first important step in the histogenesis of such neoplasia. H. pylori infection is involved in the induction of atrophic body gastritis, but documentation of H. pylori infection is difficult because of the progressive disappearance of the bacterium. Host-pathogen interactions may be investigated by means of immunoproteomics, which provides global information regarding the host humoral response to H. pylori infection and allows the identification of relevant specific and nonspecific antigens, and can be used for diagnostic or prognostic purposes. In the present review, we describe how several research groups used H. pylori immunoproteomics to investigate highly immunoreactive bacterial antigens related to the development of gastric cancer.

OLGA staging for gastritis: a tutorial

Atrophic gastritis (resulting mainly from long-standing Helicobacter pylori infection) is a major risk factor for (intestinal-type) gastric cancer development and the extent/topography of the atrophic changes significantly correlates with the degree of cancer risk. The current format for histology reporting in cases of gastritis fails to establish an immediate link between gastritis phenotype and risk of malignancy. The histology report consequently does not give clinical practitioners and gastroenterologists an explicit message of use in orienting an individual patient's clinical management. Building on current knowledge of the biology of gastritis and incorporating experience gained worldwide by applying the Sydney System for more than 15 years, an international group of pathologists (Operative Link for Gastritis Assessment) has proposed a system for reporting gastritis in terms of stage (the OLGA staging system). Gastritis staging arranges the histological phenotypes of gastritis along a scale of progressively increasing gastric cancer risk, from the lowest (stage 0) to the highest (stage IV). This tutorial aims to provide unequivocal information on how to consistently apply the OLGA staging system in routine diagnostic histology practice.