Alterations of tumor-related genes do not exactly match the histopathological grade in gastric adenocarcinomas

The Role and Clinical Implications of the Retinoblastoma (RB)-E2F Pathway in Gastric Cancer

Gastric cancer is the most common malignant tumor in the digestive tract, with very high morbidity and mortality in developing countries. The pathogenesis of gastric cancer is a complex biological process mediated by abnormal regulation of proto-oncogenes and tumor suppressor genes. Although there have been some in-depth studies on gastric cancer at the molecular level, the specific mechanism has not been fully elucidated. RB family proteins (including RB, p130, and p107) are involved in cell cycle regulation, a process that largely depends on members of the E2F gene family that encode transcriptional activators and repressors. In gastric cancer, inactivation of the RB-E2F pathway serves as a core transcriptional mechanism that drives cell cycle progression, and is regulated by cyclins, cyclin-dependent kinases, cyclin-dependent kinase inhibitors, p53, Helicobacter pylori and some other upstream molecules. The E2F proteins are encoded by eight genes (i.e. E2F1 to E2F8), each of which may play a specific role in gastric cancer. Interestingly, a single E2F such as E2F1 can activate or repress transcription, and enhance or inhibit cell proliferation, depending on the cell environment. Thus, the function of the E2F transcription factor family is very complex and needs further exploration. Importantly, the presence of H. pylori in stomach mucosa may affect the RB and p53 tumor suppressor systems, thereby promoting the occurrence of gastric cancer. This review aims to summarize recent research progress on important roles of the complex RB-E2F signaling network in the development and effective treatment of gastric cancer.

Predicting the Severity of Parkinson's Disease Dementia by Assessing the Neuropsychiatric Symptoms with an SVM Regression Model

In this study, we measured the convergence rate using the mean-squared error (MSE) of the standardized neuropsychological test to determine the severity of Parkinson's disease dementia (PDD), which is based on support vector machine (SVM) regression (SVR) and present baseline data in order to develop a model to predict the severity of PDD. We analyzed 328 individuals with PDD who were 60 years or older. To identify the SVR with the best prediction power, we compared the classification performance (convergence rate) of eight SVR models (Eps-SVR and Nu-SVR with four kernel functions (a radial basis function (RBF), linear algorithm, polynomial algorithm, and sigmoid)). Among the eight models, the MSE of Nu-SVR-RBF was the lowest (0.078), with the highest convergence rate, whereas the MSE of Eps-SVR-sigmoid was 0.110, with the lowest convergence rate. The results of this study imply that this approach could be useful for measuring the severity of dementia by comprehensively examining axial atypical features, the Korean instrumental activities of daily living (K-IADL), changes in rapid eye movement sleep behavior disorder (RBD), etc. for optimal intervention and caring of the elderly living alone or patients with PDD residing in medically vulnerable areas.

Evaluation of Gastric Carcinomas Histological Patterns in Relation to Tumors Aggressiveness Parameters

Gastric carcinomas are frequent tumors with variable growth patterns that may interfere with the evaluation of histopathological prognostic parameters of the lesions. In this study we analyzed the incidence and statistical relation of histological growth patterns depending on the prognostic parameters of gastric carcinomas for 95 cases. Pure forms were present in 82.2% of cases, from which more frequent subtypes were low grade tubular carcinomas and poorly cohesive with signet-ring cells carcinomas. Mixed forms were present in 17.8% of cases, with the highest incidence of tumors containing well differentiated tubular carcinoma and poorly differentiated papillary carcinoma areas. Analysis of the identified types and subtypes in relation to the histological prognostic parameters indicated significant differences regarding the tumor stage, the mixed subtypes being more frequent in advanced stages. Although mixed subtypes were more commonly associated with vascular and perineural invasion, the aspects were statistically insignificant. Together with tumor stage, the lymphovascular and/or perineural invasion should be taken into consideration as prognostic indicators in the postoperative management of gastric cancer.

Expression of Cytokines Interleukin-2, Interleukin-4, Interleukin-10 and Transforming Growth Factor β in Gastric Adenocarcinoma Biopsies Obtained from Mexican Patients

Objective: In this study, expression of Interleukin-2, Interleukin-4, Interleukin-10 and transforming growth factor beta in diffuse and intestinal type gastric cancers from Mexican patients was assessed for use as markers of malignancy. Methods: A total of 30 biopsies from gastric adenocarcinomas, 60% diffuse, 20% intestinal and 20% mixed in type, were studied by immunohistochemistry. Results: Regarding expression of cytokines, 23% were positive for IL-2, 26.7% for IL-4, 16.6% for IL-10 and none for TGF-β. There were found Significant statistically stage differences were noted.For example, for stages I-II 100% were IL-2 positive (p = 0.009), 87.5% were IL-4 positive (p = 0.005) and 100.0% IL-10 positive (p = 0.009). Young women were more likely to suffer gastric adenocarcinoma. In biopsies of male patients with gastric cancer, there was an increased expression of IL-2 and in biopsies from female patients in IL4. There was significantly greater detection of IL-4 and IL-10 expression in stages I and II than in stages III and IV. It was also found that IL-4, IL-10 had a higher positive expression in patients biopsies with low-level differentiations than patients with well differentiated gastric cancer in which cases were undetected. Conclusions: These results suggest that positive expression of IL-4 and IL-10 may be useful as a molecular marker to distinguish stage I and II diffuse gastric cancers which can be more readily controlled.

Molecular classification and prediction in gastric cancer

Gastric cancer, a highly heterogeneous disease, is the second leading cause of cancer death and the fourth most common cancer globally, with East Asia accounting for more than half of cases annually. Alongside TNM staging, gastric cancer clinic has two well-recognized classification systems, the Lauren classification that subdivides gastric adenocarcinoma into intestinal and diffuse types and the alternative World Health Organization system that divides gastric cancer into papillary, tubular, mucinous (colloid), and poorly cohesive carcinomas. Both classification systems enable a better understanding of the histogenesis and the biology of gastric cancer yet have a limited clinical utility in guiding patient therapy due to the molecular heterogeneity of gastric cancer. Unprecedented whole-genome-scale data have been catalyzing and advancing the molecular subtyping approach. Here we cataloged and compared those published gene expression profiling signatures in gastric cancer. We summarized recent integrated genomic characterization of gastric cancer based on additional data of somatic mutation, chromosomal instability, EBV virus infection, and DNA methylation. We identified the consensus patterns across these signatures and identified the underlying molecular pathways and biological functions. The identification of molecular subtyping of gastric adenocarcinoma and the development of integrated genomics approaches for clinical applications such as prediction of clinical intervening emerge as an essential phase toward personalized medicine in treating gastric cancer.

Histopathology-based prognostic score is independent prognostic factor of gastric carcinoma

Background

The aim of our study was to evaluate the histological characteristics and prognosis of gastric cancer.

Methods

Clinicopathlogical variables of 932 patients with gastric carcinoma admitted to the Department of Surgical Oncology at the First Hospital of China Medical University were analyzed retrospectively. Different histological characteristics of gastric cancer were summarized and assigned score according to the malignancy defined by WHO classification, the scores were stratified into 4 stage, the prognosis of different stages were analyzed by Kaplan-Meier analysis and cox regression.

Results

Among the 932 patients, 246 (26.39%) had mixed histology type of gastric cancer. Compared to the pure histological type, mixed histological type of gastric cancer was significant associated with tumor size, lymph node metastasis and depth of invasion (all P < 0.05). The 5-year survival rates of advanced and early gastric cancer patients with mixed type were 40.8% and 83.5% respectively, which were lower than those with pure type (50.0% and 95.8%, P < 0.01). Statistically significant difference with stratification of early and advanced stage could be observed between patients with the histological grading score. The data showed that the histological score could be the independent factor of prognosis.

Conclusions

The histological score is an independent factor of gastric cancer, it exerts an excellent ability to classify survival of patients with gastric carcinoma. It also provides a new strategy and parameter for evaluating the biological behavior and prognosis of gastric cancer.

Role of PTEN in gastric carcinogenesis

The PTEN (phosphatase and tensin homolog deleted on chromosome ten) gene is another important tumor suppressor gene found after p53 gene, and its encoded protein is involved in cellular differentiation, reproduction and apoptosis, as well as cellular adhesion and mobility, and genetic stability that is often lost in various human cancers. Recently, some studies have indicated that down-regulation of PTEN protein expression due to genetic or epigenetic changes, like mutation, loss of heterozygosity (LOH) and promoter hypermethylation, participates in gastric carcinogenesis. These studies could help us understand the pathogenesis of gastric cancer (GC), and show us a new molecular marker that could be used to evaluate TNM stage, histological type, or differentiation grade of GC biopsies, and GC treatment. In this article, we will focus on the functions of PTEN, the mechanisms of its inactivation in GC, and the important role of its inactivation in the development and prognosis of GC.