Genetic and expression analysis of the KCNRG gene in hepatocellular carcinomas

The potassium channels are ubiquitous multisubunit membrane proteins, and potassium-dependent alterations in the membrane potential play an important role in the proliferation of many types of cells. This study analyzed the mutation, allelic loss and expression patterns of the KCNRG gene in 77 HCCs in order to determine if the KCNRG gene, which encodes the potassium channel regulating protein, is involved in the tumorigenesis of hepatocellular carcinoma (HCC). One KCNRG missense mutation, CGT->CAT (Arg->His) was found at codon 92 within the T1 domain. Hep3B hepatoma cells were transfected with the wild- or mutant-KCNRG to determine the effect of this mutation in KCNRG. Interestingly, the suppressive cell growth activity of the mutant-type KCNRG was significantly lower than that of the wild-type KCNRG. In addition, allelic loss was detected in 17 out of 64 (26.5%) informative HCC cases, and all were hepatitis B virus (HBV)-positive. Moreover, the allelic loss was closely related to an intrahepatic metastasis (P=0.0247), higher grade (P=0.0078) and clinical stage (P=0.0071). Expression analysis revealed 22 tumor tissues to have a loss of expression of the KCNRG transcript. These results suggest that genetic alterations and the expression of KCNRG might play an important role in the development and/or progression of a subset of HCCs.

Hypermethylation of the RUNX3 gene in hepatocellular carcinoma

Methylation events play a critical role in various cellular processes including regulation of gene transcription and proliferation. Recently, RUNX3 gene, one of TGF-beta-Smads signaling transduction pathway genes, showed strong tumor-suppressor activity by regulation of epithelial proliferation and apoptosis. To elucidate the potential etiological role of the RUNX3 gene in the development of hepatocellular carcinoma (HCC), we have analyzed the methylation status of 5' CpG island of the RUNX3 gene in a series of 73 HCC tissues and 11 liver cell lines. Expectedly, promoter methylation of RUNX3 gene was found in 2 (2.7%) of 73 corresponding normal liver, whereas 30 (41.1%) of 73 HCCs and 4 (40%) of 10 liver cancer cell lines showed hypermethylation of the gene, respectively. There was no significant difference between promoter hypermethylaion and clinicopathologic parameters of primary HCC samples, including histologic grade, microvascular invasion, and clinical stage. Interestingly, demethylating agent 5-aza-2-deoxycytidine induced reactivation and more potent expression of RUNX3 gene in HCC cell lines. Our findings indicate that promoter hypermethylation of RUNX3 gene may occur as an early event in the development of HCC and that methylation may be a major mechanism for inactivation of RUNX3 gene in HCC.

Expression Pattern of KLF4 in Korean Gastric Cancers

PURPOSE: KLF4, a member of the KLF family, is a zinc finger tumor suppressor protein that is critical for gastric epithelial homeostasis. Our aim was to determine whether the altered expression of KLF4 might be associated with gastric cancer development and, if so, to determine to which pathologic parameter it is linked. MATERIALS AND METHODS: For the construction of the gastric cancer tissue microarray, 84 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression pattern of KLF4 was examined on tissue microarray slides by using immunohistochemistry and was compared with pathologic parameters, including histologic type, depth of invasion, lymph node metastasis, and peritoneal dissemination. RESULTS: The KLF4 protein was expressed in cytoplasm and nucleus of superficial and foveolar epithelial cells in the normal gastric mucosa. We found markedly reduced or loss of KLF4 expression in 43 (51.2%) of the 84 gastric cancer tissues. There was no significant correlation between KLF4 expression and pathologic parameters, including histologic type, depth of invasion, lymph node metastasis and peritoneal dissemination. CONCLUSION: Our findings suggest that altered expression of KLF4 may contribute to abnormal regulation of gastrointestinal epithelial cell growth and differentiation and to the development of Korean gastric cancer, as an early event.

A Single Nucleotide Polymorphism in the E-cadherin Gene Promoter-160 is Not Associated with Risk of Korean Gastric Cancer

Recently, the -160 C/A polymorphism, located within the regulatory region of E-cadherin promoter, has been shown to influence E-cadherin transcription by altering transcription factor binding. We examined the effect of this polymorphism on risk of gastric cancer and on histological classification of intestinal- and diffuse-type gastric cancer in 146 normal healthy individuals and 292 Korean gastric cancer patients. Genomic DNA samples were examined by polymerase chain reaction (PCR)-single strand conformational polymorphism (SSCP)-sequencing and confirmed by restriction fragment length polymorphism (RFLP). Unexpectedly, there was no significant difference in the genotype frequencies of the polymorphism between normal control and gastric cancer patients (x(2) test, p=0.433). The estimated odd ratio of C/C to A/A genotype in gastric cancer cases was 1.07 (95% confidence interval, 0.396-2.870). We also found no evidence for differences in risk for the intestinal- and diffuse-type gastric cancer. These results suggest that the -160 C/A polymorphism of the E-cadherin has no direct effect on the risk of Korean gastric cancer development and on its histological classification.

Two cases of Cushing's syndrome diagnosed by IPSS with normal or low plasma ACTH / 대한내과학회지

Cushing's syndrome results from prolonged exposure to high levels of glucocorticoid hormones. ACTH-dependent Cushing's syndrome accounts for about 85% of endogenous causes. Autonomous pituitary ACTH secretion, called Cushing's disease, is responsible for 80% of these causes, whereas ectopic ACTH secretion is responsible for 20% of them. Appropriate therapy of patients with Cushing's syndrome depends on accurate diagnosis and classification of the disorder. In addition to the history and clinical evaluation, the laboratory evaluation of a patient with Cushingoid appearance is necessary to establish the diagnosis and determine the cause of hypercortisolism. A major problem in the differential diagnosis of ACTH-dependent Cushing's syndrome is distinguishing Cushing's disease from the ectopic ACTH syndrome. Both entities can have similar clinical and laboratory features. In addition, both pituitary microadenoma and ectopic ACTH-secreting tumors may be radiologically occult. Bilateral inferior petrosal sinus and peripheral vein catheterization with simultaneous collection of samples for measurement of ACTH is one of the most specific tests available to localize the source of ACTH production. We report two cases of Cushing's syndrome diagnosed by inferior petrosal sinus sampling associated with normal or low ACTH levels on routine basal hormone assay.

A Case of Gas-forming Pyogenic Liver Abscess in a Diabetic Patient / 감염

Gas-forming pyogenic liver abscess is an uncommon, life-threatening, necrotizing infection that is usually found in poorly-controlled diabetic patients. Herein, we report a case of gas-forming liver abscess caused by Klebsiella pneumoniae, as proven by aspirated pus culture, in a 70-year old woman with diabetes mellitus. The patient was successfully managed with broadspectrum antibiotics and transhepatic percutaneous drainage and was discharged after 3 weeks of hospitalization. In conclusion, strict control of diabetes mellitus is the most important factor in the prevention of gas-forming pyogenic liver abscess.