Comparison of operative link for gastritis assessment, operative link on gastric intestinal metaplasia assessment, and TAIM stagings among men with atrophic gastritis

BACKGROUND Gastric cancer is the world’s third most lethal malignancy. Most gastric cancers develop through precancerous states of atrophic gastritis and intestinal metaplasia. Two staging systems, operative link for gastritis assessment(OLGA)and operative link on gastric intestinal metaplasia assessment(OLGIM), have been developed to detect high gastric cancer risk. European guidelines recommend surveillance for high-risk OLGA/OLGIM patients(stages Ⅲ–Ⅳ),and for those with advanced stage of atrophic gastritis in the whole stomach mucosa. We hypothesize, that by combining atrophy and intestinal metaplasia into one staging named TAIM, more patients with increased gastric cancer risk could be detected.AIM To evaluate the clinical value of the OLGA, OLGIM, and novel TAIM stagings as prognostic indicators for gastric cancer.METHODS In the Helsinki Gastritis Study, 22346 elderly male smokers from southwestern Finland were screened for serum pepsinogen I(PGI). Between the years 1989 and1993, men with low PGI values(PGI < 25 μg/L), were invited to undergo an oesophagogastroduodenoscopy. In this retrospective cohort study, 1147 men that underwent gastroscopy were followed for gastric cancer for a median of 13.7 years, and a maximum of 27.3 years. We developed a new staging system, TAIM,by combining the topography with the severity of atrophy or intestinal metaplasia in gastric biopsies. In TAIM staging, the gastric cancer risk is classified as low or high.RESULTS Twenty-eight gastric cancers were diagnosed during the follow-up, and the incidence rate was 1.72 per 1000 patient-years. The cancer risk associated positively with TAIM [Hazard ratio(HR) 2.70, 95%CI: 1.09–6.69, P = 0.03]. The risk increased through OLGIM stages 0-Ⅳ(0 vs Ⅳ: HR 5.72, 95%CI: 1.03–31.77, P for trend = 0.004), but not through OLGA stages 0–Ⅳ(0 vs Ⅳ: HR 5.77, 95%CI:0.67–49.77, P for trend = 0.10). The sensitivities of OLGA and OLGIM stages Ⅲ–Ⅳ were low, 21% and 32%, respectively, whereas that of TAIM high-risk was good, 79%. On the contrary, OLGA and OLGIM had high specificity, 85% and81%, respectively, but TAIM showed low specificity, 42%. In all three staging systems, the high-risk men had three-to four-times higher gastric cancer risk compared to the general male population of the same age.CONCLUSION OLGIM and TAIM stagings show prognostic value in assessing gastric cancer risk in elderly male smokers with atrophic gastritis.

Helicobacter pylori infection and low serum pepsinogen I level as risk factors for gastric carcinoma

AIM: To study whether examination of CagA antibodies could increase the odds ratio for gastric cancer in a casecontrol study, and how often other serum markers of gastric cancer risk could be found in Helicobacter pylorinegative patients.METHODS: H pylori CagA and parietal cell antibodies(PCAs), and serum pepsinogen Ⅰ (SPGI) levels were compared between patients with gastric cancer and controls who received endoscopic examination due to reasons other than gastrointestinal malignancy.RESULTS: The odds ratio (OR) for gastric cancer was2.9 (95% CI 1.4-5.8) in H pylori+ patients, and 2.4 (95%CI 1.2-4.9) in CagA+ patients. When results of H pylori and CagA antibodies were combined, OR increased to5.0 (95% CI 2.5-10.0). Furthermore, if cardia cancer patients were excluded, the OR increased to 6.8 (95% CI3.1-14.8). Among patients with a low SPGI level, the OR was 12.0 (95% CI 4.1-35.3). However, the risk was significant only in the older age group. The number of patients with low SPGI was significantly higher in H pylori-/CagA+ patients as compared to other cancer patients.CONCLUSION: Examination of both H pylori and CagA antibodies increases the OR for gastric cancer in our casecontrol study. CagA antibodies are important in detecting previous H pylori infection in advanced atrophic gastritis or cancer when spontaneous decline of H pylori antibodies occurs. SPGI may be helpful in screening elderly gastric cancer patients.

Gene mutations in stool from gastric and colorectal neoplasia patients by next-generation sequencing

AIM To study cancer hotspot mutations by next-generation sequencing(NGS) in stool DNA from patients with different gastrointestinal tract(GIT) neoplasms. METHODS Stool samples were collected from 87 Finnish patients diagnosed with various gastric and colorectal neoplasms, including benign tumors, and from 14 healthy controls. DNA was isolated from stools by usingthe PSP~? Spin Stool DNA Plus Kit. For each sample, 20 ng of DNA was used to construct sequencing libraries using the Ion AmpliS eq Cancer Hotspot Panel v2 or Ion AmpliS eq Colon and Lung Cancer panel v2. Sequencing was performed on Ion PGM. Torrent Suite Software v.5.2.2 was used for variant calling and data analysis.RESULTS NGS was successful in assaying 72 GIT samples and 13 healthy controls, with success rates of the assay being78% for stomach neoplasia and 87% for colorectal tumors. In stool specimens from patients with gastric neoplasia, five hotspot mutations were found in APC,CDKN2 A and EGFR genes, in addition to seven novel mutations. From colorectal patients, 20 mutations were detected in AKT1, APC, ERBB2, FBXW7, KIT, KRAS,NRAS, SMARCB1, SMO, STK11 and TP53. Healthy controls did not exhibit any hotspot mutations, except for two novel ones. APC and TP53 were the most frequently mutated genes in colorectal neoplasms, with five mutations, followed by KRAS with two mutations.APC was the most commonly mutated gene in stools of patients with premalignant/benign GIT lesions.CONCLUSION Our results show that in addition to colorectal neoplasms,mutations can also be assayed from stool specimens of patients with gastric neoplasms.