BackgroundGastric cancers with microsatellite instabilities (MSI) have been reported to be associated with favorable prognosis. However, the significance of the effect of MSI on the clinicopathological features, as well as its association with mucin phenotype, remains unclear.MethodsMSI status was assessed in 414 cases of gastric cancer using polymerase chain reaction analysis of five microsatellite loci, as recommended by National Cancer Institution criteria. The expression of mucins (MUC5AC, MUC6, MUC2, and CD10) was assessed.ResultsOut of 414 total cases of gastric cancer, 380 (91.7%), 11 (2.7%), and 23 (5.6%) were microsatellite stable (MSS), low-level MSI (MSI-L), and high-level MSI (MSI-H), respectively. Compared to MSS/MSI-L, MSI-H gastric cancers were associated with older age (p=0.010), tumor size (p=0.014), excavated gross (p=0.042), intestinal type (p=0.028), aggressive behaviors (increase of T stage [p=0.009]), perineural invasion [p=0.022], and lymphovascular emboli [p=0.027]). MSI-H gastric cancers were associated with tumor necrosis (p=0.041), tumor-infiltrating lymphocytes (≥2/high power field, p<0.001), expanding growth patterns (p=0.038), gastric predominant mucin phenotypes (p=0.028), and MUC6 expression (p=0.016). Tumor necrosis (≥10% of mass, p=0.031), tumor-infiltrating lymphocytes (p<0.001), intestinal type (p=0.014), and gastric mucin phenotypes (p=0.020) could represent independent features associated with MSI-H gastric cancers. MSI-H intestinal type gastric cancers had a tendency for poor prognosis in univariate analysis (p=0.054) but no association in Cox multivariate analysis (p=0.197).ConclusionsOur data suggest that MSI-H gastric cancers exhibit distinct aggressive biologic behaviors and a gastric mucin phenotype. This contradicts previous reports that describe MSI-H gastric cancer as being associated with favorable prognosis.

The presence of myoepithelial (ME) cells is considered an important feature in the vast majority of benign breast lesions. Recently, a case showing the absence of myoepithelium in a mammary duct with apocrine metaplasia was reported. To investigate the status of ME cells associated with apocrine metaplasia, the distribution of ME cells in 59 metaplastic and intraductal proliferative apocrine lesions was evaluated using immunohistochemical expression of p63 and Calponin. p63 showed a diminished number of ME cells and increased intermyoepithelial nuclear distance in ducts with all variants of apocrine metaplasia and proliferation compared with normal glands. In the majority of cases, Calponin showed a continuous ME layer. In 6 cases, including an apocrine papilloma, there were definitive ME gaps confirmed by both markers, in the absence of atypia and with preservation of the basement membrane. In all cases, there was frequent heterogeneity in the distribution of ME cells in ducts harboring apocrine cells and even in various papillae within papillary lesions. In summary, benign and noninvasive apocrine lesions can show reduction and occasional complete loss of ME cells. This observation is particularly important when evaluating apocrine papillary proliferations, in which the absence of ME cells may lead to overdiagnosis of atypia and/or malignancy. The observation suggests that at least 2 ME markers should be used when evaluating apocrine lesions, and that a malignant diagnosis should be based on features of the proliferating cells until more data become available on the significance, if any, of the absence of ME cells in apocrine lesions.

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A dual-gate silicon nanowire field-effect transistor (FET) fabricated on a bulk substrate is designed to perform label-free electrical detection of the avian influenza antibody. A region of a FET channel that is conventionally covered by a gate electrode is intentionally left open in the dual-gate configuration, to provide a binding site for biological species. As a result, the channel potential at this open area is affected by the polarity and charge of the biological species that binds to the opened channel. The proposed device can be used as a biosensor by comparing its electrical characteristics before and after exposing the device to biological species of interest. This detection mechanism is verified using numerical simulation and by attaching charged polyelectrolytes (PAH and PSS) to the opened channel. Additionally, the avian influenza antibody is successfully detected without a labeling step using the proposed dual-gate FET. As a biomedical diagnostic tool, the proposed biosensor offers the advantages of label-free detection capability, low-cost compatibility with the complementary metal-oxide semiconductor fabrication process, and a readout system for on-chip integration.

An analytical technique is proposed that uses an asymmetric double-gate field-effect transistor (FET) structure to characterize the electrical properties of biomolecules, including their permittivity and charge density. Using a simple measurement with the proposed FET structure, we are able to extract the physical properties (i.e., permittivity and charge density) of biomolecules. A reliable analytical tool for the characterization of biomolecules can be provided by the proposed FET structure without a complex measurement system. It is expected that the proposed method will be expanded into a universal analysis technique for the electrical evaluation of biomolecules in applications beyond biosensing. V

Despite wide acceptance of the chronic gastritis-intestinal metaplasia-dysplasia-carcinoma sequence, especially for intestinal-type gastric adenocarcinoma, the precise nature of the subtle precursor lesions of gastric cancer remains to be delineated. For example, pit dysplasia with surface foveolar maturation is not well defined, nor is its prevalence and biological characteristics well characterized. We have evaluated the surrounding gastric mucosa of 414 gastric cancers for the presence of gastric pit dysplasia. We investigated its relationship with various clinicopathological and immunophenotypic features of gastric adenocarcinoma, as well as the severity and extent of any surrounding gastritis and intestinal metaplasia. p53 expression and Ki-67 proliferation index were also evaluated. We have found that 21.0% (n=87) of gastric cancer cases showed pit dysplasia in adjacent gastric mucosa. Gastric cancers with pit dysplasia were significantly associated with older age, male sex, body/fundic location, and intestinal histologic type (P<0.05). Interestingly, gastric mucin-containing intestinal metaplasia (incomplete intestinal metaplasia) was highly associated with adenocarcinoma with pit dysplasia (P=0.000). In addition, MUC6 expression in gastric adenocarcinoma was associated with pit dysplasia (P=0.036). p53 overexpression and increased Ki-67 proliferation index were more evident in gastric pit dysplasia compared with adjacent gastric mucosa. We suggest that gastric pit dysplasia is an important candidate precursor of gastric adenocarcinoma and may represent another morphologic step in the pathogenesis of gastric adenocarcinoma, especially of intestinal type. More detailed prospective studies are needed to determine the precise significance of these findings.

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