Gastric cancer (GC) is one of the most common malignancies and remains the second leading cause of cancer-related death worldwide. There is an increasing understanding of the roles that genetic and epigenetic alterations play in GCs. Recent studies using next-generation sequencing (NGS) have revealed a number of potential cancer-driving genes in GC. Whole-exome sequencing of GC has identified recurrent somatic mutations in the chromatin remodeling gene ARID1A and alterations in the cell adhesion gene FAT4, a member of the cadherin gene family. Mutations in chromatin remodeling genes (ARID1A, MLL3 and MLL) have been found in 47% of GCs. Whole-genome sequencing and whole-transcriptome sequencing analyses have also discovered novel alterations in GC. Recent studies of cancer epigenetics have revealed widespread alterations in genes involved in the epigenetic machinery, such as DNA methylation, histone modifications, nucleosome positioning, noncoding RNAs and microRNAs. Recent advances in molecular research on GC have resulted in the introduction of new diagnostic and therapeutic strategies into clinical settings. The anti-human epidermal growth receptor 2 (HER2) antibody trastuzumab has led to an era of personalized therapy in GC. In addition, ramucirumab, a monoclonal antibody targeting vascular endothelial growth factor receptor (VEGFR)-2, is the first biological treatment that showed survival benefits as a single-agent therapy in patients with advanced GC who progressed after first-line chemotherapy. Using NGS to systematically identify gene alterations in GC is a promising approach with remarkable potential for investigating the pathogenesis of GC and identifying novel therapeutic targets, as well as useful biomarkers. In this review, we will summarize the recent advances in the understanding of the molecular pathogenesis of GC, focusing on the potential use of these genetic and epigenetic alterations as diagnostic biomarkers and novel therapeutic targets.
We suggest that this system could be a good diagnostic tool for SSA/Ps using magnifying colonoscopy.
Objective We evaluated the diagnostic performance of computed tomography (CT) as an initial radiologic test for assessing the optimal timing of colonoscopy in patients with acute lower gastrointestinal bleeding (LGIB) and investigated the effectiveness of contrast-enhanced (CE) CT for detecting colonic diverticular bleeding. Methods This was a retrospective study of 1,604 consecutive patients who visited or were referred to St. Marianna University Hospital due to acute LGIB and underwent colonoscopy within three months after presentation between September 2004 and December 2012. The clinicopathological data of the subjects were obtained from their medical records. Results Among the 1,604 patients presenting with LGIB, 879 (55%) underwent a CT scan. Elective colonoscopy was considered in cases in which typical colonic wall thickening was observed on CT, suggesting colonic inflammation or malignancy (239 patients; 27%). The diagnoses in the elective cases included ischemic colitis (38%), infectious colitis (8%), inflammatory bowel disease (8%) and malignancy (5%). Urgent colonoscopy was performed after the CT examination in 640 cases (73%). The most common presumptive CT diagnosis was diverticulum (402/640; 63%). Of the 638 patients who underwent CE-CT, diverticula were observed in 346 cases, including 104 cases of extravasation indicating ongoing diverticular bleeding. Among these 104 patients, the site of bleeding was identified in 71 subjects (68%) during colonoscopy. The rate of detection of the bleeding source on colonoscopy was significantly higher in the patients with extravasation on CE-CT than in those without extravasation on CE-CT (68% vs. 20%, respectively; p<0.001). Conclusion Urgent CT is useful for determining the optimal timing of colonoscopy in cases of acute LGIB. CE-CT may be used to depict the presence and location of active hemorrhage and provides useful information for subsequent colonoscopy, especially in patients with diverticular bleeding.
Background: Epstein-Barr virus-positive mucocutaneous ulcer (EBV-MCU) is a new category of mature B-cell neoplasms. Ulcers occur in the oropharyngeal mucosa, skin, and gastrointestinal tract. The onset of EBV-MCU is suggested to be related to the decreased immunity of the patient, the causes of which include the use of immunosuppressive agents and aging. EBV-MCU may regress spontaneously and it often has a benign course after the dose reduction or discontinuation of immunosuppressive agents or during follow-up. Here, we report the case of a patient who required surgical resection for the intestinal obstruction arising from EBV-MCU. Case presentation: A Japanese elderly male visited our hospital with chief complaints of a palpable mass and dull pain in the left upper quadrant, loss of appetite, and weight loss. Although abdominal computed tomography and total colonoscopy (TCS) revealed a tumor with circumferential ulcer in the transverse colon, histopathological analysis of a biopsy specimen of this lesion showed only nonspecific inflammation. Because the tumor spontaneously regressed during the time he underwent tests to obtain a second opinion from another hospital, TCS was reperformed on the patient. TCS revealed that the tumor decreased in size and the inflammatory changes in the surrounding mucosa tended to improve; however, tightening of the surrounding mucosa due to scarring was observed. Another histopathological analysis of a biopsy specimen showed widespread erosion of the mucosa and the formation of granulation tissue with marked infiltration of various inflammatory cells into the mucosal tissue of the large intestine. Moreover, some of the B-lymphocyte antigen CD20positive B cells were also positive for EBV-encoded small RNA-1, suggesting the possibility of EBV-MCU. Later, the tumor developed into an intestinal obstruction; thus, the transverse colon was resected. Histopathological analysis of the resected specimen demonstrated scattered Hodgkin and Reed-Sternberg-like multinucleated large B cells in addition to EBER-1positive cells. The patient was finally diagnosed as having EBV-MCU. Conclusions: This is the first report of a case of EBV-MCU that developed into an intestinal obstruction requiring surgical resection. It is necessary to consider the possibility of EBV-MCU when examining an ulcerative or tumorous lesion in the gastrointestinal tract.
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