Clinical and genomic characteristics of mucosal signet-ring cell carcinoma in Helicobacter pylori-uninfected stomach.

BACKGROUND: Gastric cancer develops even in Helicobacter pylori(H. pylori)-uninfected patients and its typical histological feature is signet ring cell carcinoma (SRCC) within the mucosal layer. However, the biological characteristics of SRCC remain unclear. We aimed to clarify the pathological and genetic features of SRCC in H. pylori-uninfected patients. METHODS: Seventeen H. pylori-uninfected patients with mucosal SRCCs were enrolled and their clinicopathological characteristics were compared with those of H. pylori-infected patients with mucosal SRCCs. Seven SRCCs without H. pylori-infected, including two invasive SRCCs, and seven H. pylori-infected SRCCs were subjected to a genetic analysis using next-generation sequencing. RESULTS: H. pylori-uninfected patients with mucosal SRCCs revealed male dominancy and a significantly higher prevalence of smokers among them as compared with the H. pylori-infected patients with SRCC. A CDH1 mutation (frame shift indel) was detected in one H. pylori-uninfected cancer not only in the mucosal SRCC but also in the invasive portion. A TP53 mutation was detected in one SRCC without H. pylori-infected. In the control group, ARID1A and TP53 mutations were detected in one SRCC each. The C to A mutation, which is a characteristic smoking-induced mutation, was not found in any of the samples. CONCLUSIONS: Some SRCCs in H. pylori-uninfected patients may have a malignant potential similar to that of SRCCs in H. pylori-infected patients. Smoking may not be the main carcinogenic factor for the development of SRCCs among the H. pylori-uninfected patients.

Gastric Cancer with Submucosal Invasion after Successful Helicobacter pylori Eradication: A Propensity Score-Matched Analysis of Patients with Annual Patient Endoscopic Survey.

BACKGROUND AND AIM: The incidence of gastric cancer occurring after successful Helicobacter pylori eradication has been increasing. We aimed to clarify the influence of eradication therapy on the ability to diagnose early gastric cancer after successful H. pylori eradication in patients who underwent annual endoscopic screening. METHODS: A total of 220 patients (179 men; mean age 71.0 years) had differentiated-type early gastric cancer that was discovered through annual endoscopic screening. Patients were categorized into 2 groups: the H. pylori-eradicated group (n = 81) and the non-eradicated control group (n = 139). After matching patients by propensity scores, we retrospectively analyzed the clinicopathological characteristics of 162 patients (81 patients in each group). Furthermore, we compared the characteristics of gastric cancer with submucosal invasion between the 2 groups. RESULTS: The prevalence of early gastric cancer with submucosal invasion was significantly higher in the eradicated group than in the control group, both before propensity score matching (16.0 vs. 7.2%, respectively; p = 0.038) and after propensity score matching of 81 pairs (16.0 vs. 4.9%, respectively; p = 0.021). In the comparative analysis of gastric cancer with submucosal invasion, there was no difference between the 2 groups with respect to factors influencing the ability to diagnose its presence endoscopically. CONCLUSION: H. pylori eradication therapy increased the prevalence of differentiated-type gastric cancer with submucosal invasion despite patients' completion of annual endoscopic screening after eradication.