Gastric cancer is the fourth leading cause of cancerrelated death in the world. Two histologically distinct types of gastric carcinoma, 'intestinal' and 'diffuse', have different epidemiological and pathophysiological features that suggest different mechanisms of carcinogenesis. A number of studies have investigated intestinal-type gastric cancers at the molecular level, but little is known about mechanisms involved in the diffuse type, which has a more invasive phenotype and poorer prognosis. To clarify the mechanisms that underlie its development and/or progression, we compared the expression profiles of 20 lasermicrobeam-microdissected diffuse-type gastric-cancer tissues with corresponding noncancerous mucosae by means of a cDNA microarray containing 23 040 genes. We identified 153 genes that were commonly upregulated and more than 1500 that were commonly downregulated in the tumors. We also identified a number of genes related to tumor progression. Furthermore, comparison of the expression profiles of diffuse-type with those of intestinal-type gastric cancers identified 46 genes that may represent distinct molecular signatures of each histological type. The putative signature of diffuse-type cancer exhibited altered expression of genes related to cellmatrix interaction and extracellular-matrix (ECM) components, whereas that of intestinal-type cancer represented enhancement of cell growth. These data provide insight into different mechanisms underlying gastric carcinogenesis and may also serve as a starting point for identifying novel diagnostic markers and/or therapeutic targets for diffuse-type gastric cancers.
To investigate the prognostic value of histologic and clinical factors in lymphomas of the gastrointestinal (GI) tract, the clinicopathologic findings in 56 Japanese patients with GI lymphomas were reviewed. They included 37 patients with gastric and 19 with intestinal lymphomas. The male to female ratio was 2.7:1 in gastric and 11:1 in small intestinal lymphomas. Histologically, all but one of intestinal lymphomas were high-grade lymphomas. Gastric lymphomas comprised 47% of low-grade and 53% of high-grade tumors. Significant factors for favorable prognosis identified by Cox's multivariate analysis were female sex, the presence of reactive lymphoid hyperplasia (RLH) in the primary site, early stage of disease, gastric lymphomas, and low-grade histologic type. The important role of chronic lymphocytic infiltration for development of gastric lymphoma was suggested by the high incidence of RLH and the intermediate lymphocytic type of lymphoma.
We analyzed sequences of the D1D2 domain of the 26S ribosomal RNA gene (26S rDNA sequence), and the region of internal transcribed spacer 1, 5.8S ribosomal RNA gene and internal transcribed spacer 2 (ITS sequence) of the miso and soy sauce fermentation yeasts, Candida etchellsii and Candida versatilis, in order to evaluate the usefulness of this sequence analysis for identification and typing of these two species. In the 26S rDNA sequence method, the numbers of base substitutions among C. etchellsii strains were up to 2 in 482 bp (99.6% similarity), and they were divided into three types (types A, B, and C). Those of C. versatilis strains were also up to 2 in 521 bp (99.6% similarity) and they were divided into three types (types 1, 2, and 3). In the ITS sequence method, those of C. etchellsii strains were zero in 433 bp (type a, 100% similarity). Those of C. versatilis were 5 in 409 bp (98.8% similarity), divided into 4 types (types I, II, III and IV). It was found that molecular methods based on the sequences of the 26S rDNA D1D2 domain and the ITS region were rapid and precise compared with the physiological method for the identification and typing of these two species.
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