The incidence of indolent lymphomas in the lymph nodes and extranodal regions is quite different. Follicular lymphoma (FL) is most common in the nodes, and it seems to be least common in the gastrointestinal (GI) tract, where mucosa-associated lymphoid tissue lymphoma arises most frequently. The authors report that the incidence of FL is unexpectedly high in the duodenum compared with other portions of the GI tract. FL was detected in only eight of 222 cases of GI lymphoma (3.6%). However, five cases of FL arose in the duodenum, which accounted for 38.5% of 13 duodenal lymphomas. Only in two patients did FL arise in either the stomach or the colorectum, and in the remaining patients FL was widespread with lymphomatous polyposis. Duodenal FL was composed of neoplastic follicles with small cleaved cells in dominance, and the immunophenotype of the lymphoma cells was CD10+, BCL-2+, CD20+, CD75+, CD79+, CD3-, CD5-, cyclin D1-, CD23-, and CD45RO-. All the patients were women age 37 to 66 years (average age, 52.4 yrs). In all patients the lymphoma was present around the ampulla of Vater, and four of five patients showed multiple small-size polyps. Although lymphoma cell infiltration was confined to the submucosa in the four patients examined, the regional lymph nodes were involved partially in two patients without distant metastasis. All patients are alive at 2 to 50 months of follow up (average, 27 mos), which is comparable with the prognosis for indolent nodal lymphomas. These results suggest that the duodenum has a distinct background of histogenesis of the lymphomas and that biopsy specimens from the duodenum with multiple polyps should be examined carefully.
Cholangiocellular carcinoma (CC), the second most common primary liver cancer, is associated with a poor prognosis. It has been shown that CCs harbor alterations of a number of tumor-suppressor genes and oncogenes, yet key regulators for tumorigenesis remain unknown. Here we have generated a mouse model that develops CC with high penetrance using liver-specific targeted disruption of tumor suppressors SMAD4 and PTEN. In the absence of SMAD4 and PTEN, hyperplastic foci emerge exclusively from bile ducts of mutant mice at 2 months of age and continue to grow, leading to tumor formation in all animals at 4-7 months of age. We show that CC formation follows a multistep progression of histopathological changes that are associated with significant alterations, including increased levels of phosphorylated AKT, FOXO1, GSK-3β, mTOR, and ERK and increased nuclear levels of cyclin D1. We further demonstrate that SMAD4 and PTEN regulate each other through a novel feedback mechanism to maintain an expression balance and synergistically repress CC formation. Finally, our analysis of human CC detected PTEN inactivation in a majority of p-AKT-positive CCs, while about half also lost SMAD4 expression. These findings elucidate the relationship between SMAD4 and PTEN and extend our understanding of CC formation.
There is a risk of developing gastric cancer of both the intestinal and diffuse types even after the cure of H. pylori infection and extinction of gastric inflammation. It is important to inform patients about the risk of gastric cancer after eradication therapy and offer them surveillance endoscopy.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.