Genetic features of multicentric/multifocal intramucosal gastric carcinoma.

Chronic gastritis caused by Helicobacter pylori (H. pylori) infection could lead to the development of gastric cancer. The finding that multiple gastric cancers can develop synchronously and/or metachronously suggests the development of field cancerization in chronically inflamed, H. pylori-infected gastric mucosa. The genetic basis of multiple tumorigenesis in the inflamed stomach, however, is not well understood. In this study, we analyzed the microsatellite instability (MSI) status and copy number aberrations (CNAs) of 41 multiple intramucosal early gastric cancers that synchronously or metachronously developed in 19 patients with H. pylori infection. Among the 41 intramucosal gastric carcinomas, 9 (22%) exhibited MSI, and the remaining 32 (78%) exhibited the microsatellite stable (MSS) phenotype. Metachronous multiple intramucosal gastric carcinoma exhibit inter-tumor heterogeneity by individually acquiring genetic aberrations. All synchronous multiple intramucosal gastric carcinoma pairs shared a common MSI/MSS profile, and CNA analysis revealed that synchronous multiple intramucosal gastric carcinoma pairs with the MSS phenotype shared common aberrations of representative tumor-suppressor genes, including focal deletion of APC, TP53, CDKN2A, and CDKN2B. Multiregional CNA analysis revealed that heterogeneous gene amplifications/deletions, including PDL1 amplification, evolved under the presence of shared "trunk" genetic alterations in a subpopulation of individual intramucosal gastric carcinomas. These data suggest that multiple gastric carcinomas develop in a multicentric/multifocal manner exhibiting features of inter- and intra-tumor heterogeneity in H. pylori-infected gastric mucosa, whereas synchronous multiple intramucosal gastric carcinomas could share partially common genetic alterations, possibly via common oncogenic pathways.

Leptin receptor somatic mutations are frequent in HCV-infected cirrhotic liver and associated with hepatocellular carcinoma.

BACKGROUND & AIMS: Hepatocellular carcinoma develops in patients with chronic hepatitis or cirrhosis via a stepwise accumulation of various genetic alterations. To explore the genetic basis of development of hepatocellular carcinoma in hepatitis C virus (HCV)-associated chronic liver disease, we evaluated genetic variants that accumulate in nontumor cirrhotic liver. METHODS: We determined the whole exome sequences of 7 tumors and background cirrhotic liver tissues from 4 patients with HCV infection. We then performed additional sequencing of selected exomes of mutated genes, identified by whole exome sequencing, and of representative tumor-related genes on samples from 22 cirrhotic livers with HCV infection. We performed in vitro and in vivo functional studies for one of the mutated genes. RESULTS: Whole exome sequencing showed that somatic mutations accumulated in various genes in HCV-infected cirrhotic liver tissues. Among the identified genes, the leptin receptor gene (LEPR) was one of the most frequently mutated in tumor and nontumor cirrhotic liver tissue. Selected exome sequencing analyses detected LEPR mutations in 12 of 22 (54.5%) nontumorous cirrhotic livers. In vitro, 4 of 7 (57.1%) LEPR mutations found in cirrhotic livers reduced phosphorylation of STAT3 to inactivate LEPR-mediated signaling. Moreover, 40% of Lepr-deficient (C57BL/KsJ-db/db) mice developed liver tumors after administration of thioacetamide compared with none of the control mice. CONCLUSIONS: Based on analysis of liver tissue samples from patients, somatic mutations accumulate in LEPR in cirrhotic liver with chronic HCV infection. These mutations could disrupt LEPR signaling and increase susceptibility to hepatocarcinogenesis.

Recent Advances in the Management of Chronic Hepatitis B Including Suppression of Hepatocellular Carcinoma by Entecavir and Interferon.

At present, for adults with chronic hepatitis B virus (HBV) infection, two new analogues, entecavir (ETV) and tenofovir, are recommended as the first-line therapy by the EASL (European Association for the Study of the Liver), AASLD (American Association for the Study of Liver Diseases), and APASL (Asian Pacific Association for the Study of the Liver) guidelines. The use of pegylated interferon-α (PEG IFN-α) is recommended as the first-line therapy instead of standard IFN-α according to the above 3 guidelines. In this paper, the aim was to assess: (1) the long-term efficacy and safety as well as the resistance to ETV and tenofovir disoproxil fumarate (TDF); (2) the efficacy of PEG IFN-α; (3) the role of combination therapy with IFN plus two analogues, such as lamivudine and ETV; (4) the efficacy and safety of two analogues with cirrhosis, and (5) suppression of hepatocellular carcinoma (HCC) by ETV and IFN treatment. The results are as follows: (1) both ETV and TDF showed long-term efficacy and safety; (2) PEG IFN-α resulted in a greater decline in HBV DNA levels and a higher rate of HBeAg seroconversion; (3) combination therapy with IFN plus two analogues did not elevate the rate of sustained responses; (4) both ETV and TDF showed efficacy and safety with cirrhosis (ETV especially displayed efficacy and safety with decompensated cirrhosis), and (5) suppression of HCC was observed by ETV and IFN.

[A case of endocrine carcinoma of the cecum treated with CDDP/VP-16].

A 41-year-old man was admitted to our hospital because of multiple liver tumors. Colonoscopy showed a mass lesion in the cecum. He was given a diagnosis of endocrine cell carcinoma by immunostaining technique, and received chemotherapy of CAPOX regimen for 3 courses. After that, he underwent second-line chemotherapy of EP(CDDP/VP-16)regimen due to deterioration of his performance status(PS), and his tumor marker NSE. He then showed dramatically improved PS, and improvement in the size of liver mets and NSE(4. 3mg/mL).

Expansion of Gastric Intestinal Metaplasia with Copy Number Aberrations Contributes to Field Cancerization.

Intestinal metaplasia (IM) is a risk factor for gastric cancer following infection with Helicobacter pylori. To explore the susceptibility of pure gastric IM to cancer development, we investigated genetic alterations in single IM gastric glands. We isolated 50 single IM or non-IM glands from the inflamed gastric mucosa of 11 patients with intramucosal gastric carcinoma (IGC) and 4 patients without IGC; 19 single glands in the noninflamed gastric mucosa of 11 individuals from our cohort and previous dataset were also included as controls. Whole-exome sequencing of single glands revealed significantly higher accumulation of somatic mutations in various genes within IM glands compared with non-IM glands. Clonal ordering analysis showed that IM glands expanded to form clusters with shared mutations. In addition, targeted-capture deep sequencing and copy number (CN) analyses were performed in 96 clustered IM or non-IM gastric glands from 26 patients with IGC. CN analyses were also performed on 41 IGC samples and The Cancer Genome Atlas-Stomach Adenocarcinoma datasets. These analyses revealed that polyclonally expanded IM commonly acquired CN aberrations (CNA), including amplification of chromosomes 8, 20, and 2. A large portion of clustered IM glands typically consisted of common CNAs rather than other cancer-related mutations. Moreover, the CNA patterns of clustered IM glands were similar to those of IGC, indicative of precancerous conditions. Taken together, these findings suggest that, in the gastric mucosa inflamed with H. pylori infection, IM glands expand via acquisition of CNAs comparable with those of IGC, contributing to field cancerization. SIGNIFICANCE: This study contributes to our understanding of gastric intestinal metaplasia as a risk factor for gastric adenocarcinoma via their multifocal expansion and acquisition of CNAs and somatic mutations.