Different phenotypes of gastric fundic gland polyposis and cancer in patients with familial adenomatous polyposis depending on Helicobacter pylori infection

Gastric fundic gland polyposis and cancer development after eradication of Helicobacter pylori in patient with gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS)

A 44-year-old woman with gastric cancer (GC) and fundic gland polyposis (FGPs) was referred to our hospital for further diagnosis and treatment. She successfully underwent eradication therapy for Helicobacter pylori (HP) 6 years ago, but did not exhibit FGPs at that time. When she underwent an esophagogastroduodenoscopy 2, 4, and 5 years after the eradication of HP, her imaging results revealed the existence of FGPs which gradually increased in her gastric fundus and body. Gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS) was suspected and a mutational analysis was performed, revealing an APC promoter 1B variant c.-191T > C. A robotic total gastrectomy with lymphadenectomy was performed. Histopathological analysis of the surgical specimens revealed GC with no lymph node metastasis. GAPPS is characterized by GC and FGPs. However, our case shows different gastric phenotypes that are dependent on the status of HP infection.

Ehrlichia chaffeensis TRP120 ubiquitinates tumor suppressor APC to modulate Hippo and Wnt signaling

Ehrlichia chaffeensis: TRP120 is a multifunctional effector that acts as a ligand mimic to activate evolutionary conserved eukaryotic signaling pathways Notch, Wnt, Hedgehog and Hippo. In addition, TRP120 is also a HECT E3 ubiquitin ligase known to ubiquitinate several host cell regulatory proteins (FBW7, PCGF5 and ENO-1) for degradation. We previously determined that TRP120 ubiquitinates the Notch negative regulator, FBW7, to maintain Notch signaling and promote infection. In this study, we investigated a potential mechanism used by Ehrlichia chaffeensis to maintain Hippo and Wnt signaling by ubiquitinating the tumor suppressor, adenomatous polyposis coli (APC), a negative regulator of Wnt and Hippo signaling. We determined that APC was rapidly degraded during E. chaffeensis infection despite increased APC transcription. Moreover, RNAi knockdown of APC significantly increased E. chaffeensis infection and coincided with increased active Yap and β-catenin in the nucleus. We observed strong nuclear colocalization between TRP120 and APC in E. chaffeensis-infected THP-1 cells and after ectopic expression of TRP120 in HeLa cells. Additionally, TRP120 interacted with both APC full length and truncated isoforms via co-immunoprecipitation. Further, TRP120 ubiquitination of APC was demonstrated in vitro and confirmed by ectopic expression of a TRP120 HECT Ub ligase catalytic site mutant. This study identifies APC as a TRP120 HECT E3 Ub ligase substrate and demonstrates that TRP120 ligase activity promotes ehrlichial infection by degrading tumor suppressor APC to positively regulate Hippo and Wnt signaling.

Two Cases, Too Little, Too Late: Surveillance for Gastric Cancer in Patients with FAP

Familial adenomatous polyposis is an autosomal dominant disease due to a mutation in the adenomatous polyposis coli (APC) gene. The disease, characterized by the development of adenomas throughout the colon and rectum, is also associated with extracolonic manifestations including gastric fundic polyps and cancer. In this report, we describe two patients with FAP with advanced gastric adenocarcinoma who received systemic chemotherapy. We reviewed the literature published over the past two decades on gastric cancer in FAP patients to assess the clinical course of this disease. Due to its recent increased incidence in Western countries, close endoscopic surveillance to detect early gastric neoplastic lesions is recommended.

Histopathological Features of Helicobacter pylori Infection in Gastric Mucosa

Objective

To investigate the histopathological characteristics of Helicobacter pylori (Hp) infection in the gastric mucosa in the process from occurrence to intraepithelial neoplasia.

Methods

Specimens obtained from the endoscopic biopsy and endoscopic submucosal dissection of 2457 cases of gastric Hp infection were observed and assessed in detail using histology and immunohistochemistry techniques. The condition was divided according to the histopathological characteristics of gastric mucosal damage caused by Hp infection. The histopathological characteristics and immunophenotype of each stage were subsequently elucidated.

Results

Helicobacter pylori is initially implanted in the mucus layer covered by the epithelium on the surface of the gastric mucosa. It then selectively adheres to the cytoplasm of the surface mucus cells, which makes the oval and spherical particles containing mucus that is wrapped by the bounded membrane in the cytoplasm on the nucleus of the surface mucus cells disappear, while the cytoplasm undergoes spiderweb-like vacuolar degeneration. This leads to the proliferation and transformation of the surface mucous cells before developing into intraepithelial neoplasia. In the process of histomorphology, mucosal ulcers, mucosal lymphoid tissue proliferation, gland atrophy, intestinal epithelial metaplasia, mucosa-associated lymphoid tissue lymphoma, and adenocarcinoma may occur. In this study, the condition was divided into five stages according to the histopathological characteristics of gastric mucosal damage caused by Hp infection, as well as the degree of gastric mucosal damage and involvement depth as follows: the mucus infection stage, the surface epithelial cell infection stage, the lamina propria lesion stage, the mucosal atrophy stage, and the intraepithelial neoplasia stage.

Conclusion

Understanding the histopathological characteristics of gastric Hp infection in terms of its occurrence and development into intraepithelial neoplasia is conducive to the precise treatment and tracking of malignant cell transformation, and is of great significance in controlling the occurrence and development of gastric cancer.

Endoscopic Findings and Treatment of Gastric Neoplasms in Familial Adenomatous Polyposis

PURPOSE

Gastric neoplasia is a common manifestation of familial adenomatous polyposis (FAP). This study aimed to elucidate the clinical characteristics, endoscopic features including fundic gland polyposis (FGPsis), and treatment outcomes of gastric neoplasms (GNs) in patients with FAP.

MATERIALS AND METHODS

A total of 35 patients diagnosed with FAP, including nine patients from four pedigrees who underwent esophagogastroduodenoscopy (EGD), were investigated regarding patient characteristics, GN morphology, and treatment outcomes.

RESULTS

Twenty-one patients (60.0%) had 38 GNs; 33 (86.8%) and 5 (13.2%) were histologically diagnosed with adenocarcinoma and adenoma, respectively. There were no specific patient characteristics related to GNs. Nodule-type GNs were more prevalent in patients with FGP than without (52.2% vs. 0.0%, P=0.002) in the upper body of the stomach. Conversely, depressed-type GNs were fewer in patients with FGPsis than in those without (13.0% vs. 73.3%, P<0.001). Slightly elevated-type GNs were observed in both groups (34.8% vs. 20.0%, P=0.538). Even within pedigrees, the background gastric mucosa and types of GNs varied. In total, 24 GNs were treated with endoscopic submucosal dissection (ESD) and eight with endoscopic mucosal resection (EMR). EMR was selected for GNs with FGPsis because of the technical difficulty of ESD, resulting in a lower en bloc resection rate (62.5% vs. 100%, P=0.014).

CONCLUSIONS

Our study indicates the necessity of routine EGD surveillance in patients diagnosed with FAP. Notably, the morphology and location of GNs differed between patients with and without FGPsis. Endoscopic treatment and outcomes require more attention in cases of FGPsis.

Genetic alteration of colorectal adenoma-carcinoma sequence among gastric adenocarcinoma and dysplastic lesions in a patient with attenuated familial adenomatous polyposis

Background

Familial adenomatous polyposis (FAP) is characterized by colorectal polyposis and adenocarcinoma that is frequently accompanied by extracolonic neoplasm. The risk of gastric carcinoma is increasing in Western FAP patients as well as Asian patients.

Methods

We report the case of an FAP patient with fundic gland polyposis who developed gastric adenocarcinoma and metachronous pyloric gland adenomas. These tumors were endoscopically resected, and immunohistochemistry with gastric mucin (i.e., MUC6, MUC5AC) showed that the tumors belonged to the gastric subtype. Somatic mutation profiles were determined by target amplicon sequencing using a next‐generation sequencer.

Results

Germline APC variant c.5782delC was found by direct sequencing and somatic KRAS mutations in these tumors were identified by next‐generation sequencing. Different KRAS mutation alleles (KRAS p.Gly12Ala, p.Gly12Arg, and p.Gly12Asp) indicated these dysplastic lesions developed from a distinct origin in fundic gland polyposis. Sequential mutations of the APC and KRAS were judged—based on a database search—to be characteristic of the adenoma‐carcinoma sequence in colorectal carcinogenesis.

Conclusion

The colonic adenoma‐carcinoma sequence among gastric adenocarcinoma and dysplastic lesions was indicated in FAP‐associated gastric carcinogenesis.