Han-Kwang Yang

EGFR in gastric carcinomas: prognostic significance of protein overexpression and high gene copy number

Aims:u2002 Epidermal growth factor receptor (EGFR) expression has been observed in a variety of solid tumours with the potential of new targeted therapeutic agents. The aim was to evaluate the EGFR status of gastric carcinoma (GC) using immunohistochemistry (IHC) and fluorescence in situ hybridization (FISH).

Distinct Clinical Features and Outcomes of Gastric Cancers with Microsatellite Instability

Microsatellite instability (MSI) is a hallmark of the DNA mismatch repair deficiency that is one of the pathways of gastric carcinogenesis. Clinicopathologic characteristics of MSI+ gastric cancers remain unclear. To determine the correlation between MSI status and clinical features, we analyzed 327 consecutive gastric cancers for the occurrence of MSI in the BAT-26 marker. Because it has been proven that MSI at BAT-26 reflects the MSI+ phenotype, cancers with alteration at BAT-26 were categorized as having the MSI+ phenotype. The expressions of hMLH1, hMSH2, p53, MUC1, MUC2, and CEA were evaluated immunohistochemically using the tissue array method. The MSI+ phenotype was found in 9.5% (31/327) of gastric cancers examined. MSI+ gastric cancers were significantly associated with older age, antral location, Borrmanns gross Type II, intestinal subtype, lower prevalence of lymph node metastasis, and lower pTNM stage (P < .05). By multivariate logistic regression, MSI+ gastric cancers had a lower prevalence of lymph node metastasis independent of tumor invasion (P < .001). MSI+ gastric cancers displayed frequent frameshift mutations of transforming growth factor-β type II receptor (90.3%), BAX (61.3%), hMSH3 (38.7%), and E2F4 (61.3%) genes and diminished hMLH1 (24/31) or hMSH2 (4/31) expressions. The MSI+ phenotype correlated with patient survival in advanced gastric carcinoma (P = .046). In conclusion, MSI+ phenotype in gastric cancers was found to have distinct clinicopathologic characteristics and to be predictive of a favorable outcome in advanced carcinoma.

Manganese superoxide dismutase expression correlates with a poor prognosis in gastric cancer.

Objective: The biologic significance of superoxide dismutase (SOD) in transformed gastric carcinoma cells is unclear. The aim of this study was to examine the role of SOD as a prognostic indicator of gastric carcinomas and its association with other clinicopathological factors. Methods: Expression of MnSOD and Cu/ZnSOD was evaluated immunohistochemically in gastric carcinomas and adenomas using tissue-array methods. The correlation between SOD immunoreactivity and clinical outcome or clinicopathological factors was investigated. Results: MnSOD expression was associated with a poor patient prognosis and was strong in advanced gastric cancer, in the well-differentiated type and in the presence of lymphoid stroma (p < 0.05). On the other hand, there was no association between Cu/ZnSOD expression and patient survival. Cu/ZnSOD immunoreactivity was strong in advanced gastric cancer and in the presence of lymphoid stroma (p < 0.05) and was weak in signet ring cell type. Conclusion: MnSOD immunoreactivity is significantly associated with poor outcome in gastric carcinoma patients although both MnSOD and Cu/ZnSOD have a connection with several clinicopathological parameters with some overlap.

Operating Room to Bench for Gastric Cancer

Gastric cancer is the most common cancer in Korea, with an age-standardized rate of 61.2 in males and 23.9 in females (in 2007), one of the highest in the world. Using a large gastric tissue depository and the extensive clinical experience gained from gastric cancer surgery, we work as a ‘translational researcher’ to apply basic research tools and results to the clinical field. We are also interested in providing answers to the questions in the operating room using the methods of basic research. I would like to introduce our research activities in this review paper.