Anti-SARS-CoV-2 Neutralizing Antibody Responses after Two Doses of ChAdOx1 nCoV-19 vaccine (AZD1222) in Healthcare Workers / 감염과화학요법

Background@#The kinetics of neutralizing antibodies against severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) play an important role in evaluating vaccine efficacy and durability, herd immunity, additional vaccination, and prediction models of immune protection against coronavirus disease 2019. @*Materials and Methods@#Serum collection times were 4 and 8 weeks after 1st inoculation of AZD1222 (AstraZeneca, Cambridge, UK), and 2 and 16 weeks after 2nd inoculation with 12-week dosing intervals. Neutralizing antibody (Nab) titers were measured indirectly using commercially available R-FIND SARS-CoV-2 Neutralizing Antibody ELISA Kit (SG Medical Inc., Seoul, Korea). Possible influences of gender, age, and adverse events on neutralizing antibody titer were also investigated. @*Results@#Nab titers (median inhibition %) started to decrease shortly after reaching peaks.This decrease was more pronounced in the elderly group (≥56 years) than in the young group (≤39 years) at 8 weeks (49.5% vs. 55.4%, P = 0.021) and 16 weeks (40.6% vs. 53.9%, P = 0.006) after the 1st and 2nd inoculation. And Nab titers were inversely correlated with age in the 8-week (r = -0.2091, P = 0.0284) and the 28-week group (r = -0.2811, P = 0.0029). Seropositive conversion of Nab reached 89.1% and 100% following 1st and 2nd inoculation. This 100% seropositivity was dropped sharply to 74.5% after 16 weeks. Compared to subjects without adverse events (51.8%), median inhibition was higher in subjects with one or more systemic adverse events (74.2%, P = 0.0203) or those with one or more local and systemic adverse events (77.1%, P = 0.0003). @*Conclusion@#Nab induced by AZD1222 (AstraZeneca, UK) vaccination started to degrade shortly after the production period. Nab titers were lower in the elderly than in younger group during the degradation period. This seems to be because the degradation process of Nab is more pronounced in the elderly. This may explain why the frequency of breakthrough infections, disease severity, and mortality were higher in the elderly and may require revaccination to ensure robust immunity.

The Role of Gastrokine 1 in Gastric Cancer

Homeostatic imbalance between cell proliferation and death in gastric mucosal epithelia may lead to gastritis and gastric cancer. Despite abundant gastrokine 1 (GKN1) expression in the normal stomach, the loss of GKN1 expression is frequently detected in gastric mucosa infected with Helicobacter pylori, as well as in intestinal metaplasia and gastric cancer tissues, suggesting that GKN1 plays an important role in gastric mucosal defense, and the gene functions as a gastric tumor suppressor. In the stomach, GKN1 is involved in gastric mucosal inflammation by regulating cytokine production, the nuclear factor-kappaB signaling pathway, and cyclooxygenase-2 expression. GKN1 also inhibits the carcinogenic potential of H. pylori protein CagA by binding to it, and up-regulates antioxidant enzymes. In addition, GKN1 reduces cell viability, proliferation, and colony formation by inhibiting cell cycle progression and epigenetic modification by down-regulating the expression levels of DNMT1 and EZH2, and DNMT1 activity, and inducing apoptosis through the death receptor-dependent pathway. Furthermore, GKN1 also inhibits gastric cancer cell invasion and metastasis via coordinated regulation of epithelial mesenchymal transition-related protein expression, reactive oxygen species production, and PI3K/Akt signaling pathway activation. Although the modes of action of GKN1 have not been clearly described, recent limited evidence suggests that GKN1 acts as a gastric-specific tumor suppressor. This review aims to discuss, comment, and summarize the recent progress in the understanding of the role of GKN1 in gastric cancer development and progression.

Gastrokine 1 Expression in the Human Gastric Mucosa Is Closely Associated with the Degree of Gastritis and DNA Methylation

PURPOSE: Gastrokine 1 plays an important role in gastric mucosal defense. Additionally, the Gastrokine 1-miR-185-DNMT1 axis has been shown to suppress gastric carcinogenesis through regulation of epigenetic alteration. Here, we investigated the effects of Gastrokine 1 on DNA methylation and gastritis. MATERIALS AND METHODS: Expression of Gastrokine 1, DNMT1, EZH2, and c-Myc proteins, and the presence of Helicobacter pylori CagA protein were determined in 55 non-neoplastic gastric mucosal tissue samples by western blot analysis. The CpG island methylation phenotype was also examined using six markers (p16, hMLH1, CDH1, MINT1, MINT2 and MINT31) by methylation-specific polymerase chain reaction. Histological gastritis was assessed according to the updated Sydney classification system. RESULTS: Reduced Gastrokine 1 expression was found in 20 of the 55 (36.4%) gastric mucosal tissue samples and was closely associated with miR-185 expression. The Gastrokine 1 expression level was inversely correlated with that of DNMT1, EZH2, and c-Myc, and closely associated with the degree of gastritis. The H. pylori CagA protein was detected in 26 of the 55 (47.3%) gastric mucosal tissues and was positively associated with the expression of DNMT1, EZH2, and c-Myc. In addition, 30 (54.5%) and 23 (41.9%) of the gastric mucosal tissues could be classified as CpG island methylation phenotype-low and CpG island methylation phenotype-high, respectively. Reduced expression of Gastrokine 1 and miR-185, and increased expression of DNMT1, EZH2, and c-Myc were detected in the CpG island methylation phenotype-high gastric mucosa. CONCLUSIONS: Gastrokine 1 has a crucial role in gastric inflammation and DNA methylation in gastric mucosa.

TNF-alpha and TNF-beta Polymorphisms are Associated with Susceptibility to Osteoarthritis in a Korean Population

BACKGROUND: The tumor necrosis factor (TNF) is believed to play an important role in the pathophysiology of osteoarthritis (OA). Evidence shows that genetic polymorphisms make substantial contributions to the etiology of OA. METHODS: We investigated the genotypes TNF-alpha and TNF-beta in 301 OA patients and 291 healthy subjects as controls. We employed a polymerase chain reaction-restriction fragment length polymorphism and a polymerase chain reaction-single strand conformation polymorphism assay to identify the genotypes TNFA -G308A and TNFB +G252A, respectively. RESULTS: For TNFA -G308A, the percentages of genotypes GG, AG, and AA were 26.3% (79/301), 62.5% (188/301), and 11.3% (34/301) in OA patients and 88.7% (258/291), 11.3% (33/291), and 0% (0/291) in controls. For TNFB +G252A, the percentages of genotypes GG, AG, and AA were 15.3% (46/301), 41.9% (126/301), and 42.9% (129/301) in OA patients and 12% (35/291), 52.6% (153/291), and 35.4% (103/291) in controls. There were significant differences in genotypes and alleles of TNFA -308 between OA patients and controls (p<0.0001) and in alleles of TNFB +252 (p=0.0325). The risk of OA was significantly higher for carriers of the TNFA -308A allele and the TNFB +252 AA homozygote (p=0.0224). CONCLUSIONS: The results suggest close relationships between TNFA -G308A and TNFB +G252A polymorphisms and individual susceptibility to OA in the Korean population.

Amplification of the UQCRFS1 Gene in Gastric Cancers

PURPOSE: The specific aim of this study is to unravel a DNA copy number alterations, and to search for novel genes that are associated with the development of Korean gastric cancer. MATERIALS AND METHODS: We investigated a DNA copy number changes in 23 gastric adenocarcinomas by array-comparative genomic hybridization and quantitative real-time polymerase chain reaction analyses. Besides, the expression of UQCRFS1, which shows amplification in array-CGH, was examined in 186 gastric cancer tissues by an immunohistochemistry, and in 9 gastric cancer cell lines, as well as 24 gastric cancer tissues by immunoblotting. RESULTS: We found common gains at 48 different loci, and a common loss at 19 different loci. Amplification of UQCRFS1 gene at 19q12 was found in 5 (21.7%) of the 23 gastric cancers in an array-comparative genomic hybridization and DNA copy number were increased in 5 (20.0%) out of the 25 gastric cancer in quantitative real-time polymerase chain reaction. In immunohistochemistry, the overexpression of the protein was detected in 105 (56.5%) out of the 186 gastric cancer tissues. Statistically, there was no significant relationship between the overexpression of UQCRFS1 and clinicopathologic parameters (P>0.05). In parallel, the overexpression of UQCRFS1 protein was confirmed in 6 (66.7%) of the 9 gastric cancer cell lines, and 12 (50.0%) of the 24 gastric cancer tissues by immunoblotting. CONCLUSIONS: These results suggest that the overexpression of UQCRFS1 gene may contribute to the development and/or progression of gastric cancer, and further supported that mitochondrial change may serve as a potential cancer biomarker.

Copy Number Alterations of BCAS1 in Squamous Cell Carcinomas

BACKGROUND: Breast carcinoma amplified sequence 1 (BCAS1), located in 20q13, is amplified and overexpressed in breast cancers. Even though BCAS1 is expected to be an oncogene candidate, its contribution to tumorigenesis and copy number status in other malignancies is not reported. To elucidate the role of BCAS1 in squamous cell carcinomas, we investigated the copy number status and expression level of BCAS1 in several squamous cell carcinoma cell lines, normal keratinocytes and primary tumors. METHODS: We quantitated BCAS1 gene by real-time polymerase chain reaction (PCR). Expression level of BCAS1 was measured by real-time reverse transcription-PCR and immunoblot. RESULTS: Seven (88%) of 8 squamous cell carcinoma cell lines showed copy number gain of BCAS1 with various degrees. BCAS1 gene in primary tumors (73%) also showed copy number gain. However, expression level did not show a linear correlation with copy number changes. CONCLUSIONS: We identified copy number gain of BCAS1 in squamous cell carcinomas. Due to lack of linear correlation between copy numbers of BCAS1 and its expression level, we could not confirm that the overexpression of BCAS1 is a common finding in squamous cell carcinoma cell lines. However, this study shows that the copy number gain of BCAS1 is a common finding in squamous cell carcinomas.

Molecular Pathogenesis of Gastric Cancer

In this article, I will survey the major genetic susceptibility and somatic genetic alterations involved in gastric cancer and adenoma. These include germline and somatic genetic alterations in oncogenes, tumor suppressor genes, and apoptosis-related genes. A small proportion of gastric cancers arise as a consequence of hereditary predisposition caused by specific germline mutations in E-cadherin, mismatch repair genes, adenomatous polyposis coli, and STK11. Aberrant expression of activation induced cytidine deaminase, triggered by Helicobacter pylori infection, accumulates with genetic mutations of oncogenes and tumor suppressor genes, including p53 and CTNNB1. Inactivation of trefoil factor family 1, which is a gastric specific tumor suppressor, occurs in gastric adenomas and cancers. Ectopic expression of CDX2 leads to intestinal metaplasia and defective Cdx2 expression accelerates the transformation of metaplastic cells to gastric cancer. Genetic alterations of p53 and genes related to Wnt signaling pathway and microsatellite instability occur early in the development of gastric carcinoma, indicating that detection of certain genetic alterations in adenomas may be indicative of malignant transformation. In addition, inactivation of apoptosis-inducing gene caused by mutations may be an escaping mechanism against apoptotic cell death and contribute to the progression of gastric cancer. Although the results of many studies are contradictory with one another, genetic alterations in oncogenes and tumor suppressor genes are present even in gastric adenoma and increase in frequency during multistep gastric carcinogenesis. Genetic alterations described herein, and from as yet unidentified target genes in gastric cancer cells, will guide us towards more effective risk assessment, diagnosis, and treatment.

Growth Differentiation Factor 5 (GDF5) Core Promoter Polymorphism Is Not Associated with Susceptibility to Osteoarthritis of the Knee in the Korean Population

BACKGROUND: Osteoarthritis (OA) is a common disease characterized by degenerating joint cartilage in the knee, hip, and hand. A functional single nucleotide polymorphism (SNP) +104T/C; rs143383 in the 5' untranslated region of the growth differentiation factor 5 (GDF5) gene was recently associated with susceptibility to OA in the Japanese and Chinese populations. METHODS: To investigate whether this association is present in the Korean population, the frequency of the polymorphism was investigated in 276 patients with knee OA and 298 healthy subjects as controls. Polymorphism analysis was performed by amplifying the core promoter region of the GDF5 gene and digesting it with the BsiEI restriction enzyme. RESULTS: The frequency of the TT, CT, and CC genotypes was 54.3% (150/276), 41.7% (115/276), and 4.0% (11/276), respectively, in patients with OA, and 53.4% (159/298), 37.9% (113/298), and 8.7% (26/298), respectively, in healthy controls. No significant differences in genotypic or allelic frequencies of the +104T/C SNP of the GDF5 gene were observed between patients with OA and controls. Also, no significant differences in allelic and genotypic frequencies were found when the individuals were stratified by age and gender. CONCLUSIONS: The results suggest that the +104T/C; rs143383 GDF5 core promoter polymorphism is not a risk factor for OA in the Korean population.

Genetic and Expression Analysis of the SIRT1 Gene in Gastric Cancers

PURPOSE: Silent mating-type information regulation 2 homologue 1 (SIRT1) is a nicotinamide adenine dinucleotide-dependent deacetylase. SIRT1 plays an important role in the regulation of cell death/survival and stress response in mammals. The aim of this study was to investigate whether the SIRT1 gene is involved in the development or progression of gastric cancers. MATERIALS AND METHODS: SIRT1 and p53 genes in 86 gastric cancers were examined for genetic alterations by PCR-single strand conformation polymorphism sequencing, as well as SIRT1 protein expression in 170 gastric cancers by immunohistochemistry. RESULTS: In the genetic analysis, we found SIRT1 and p53 mutations in two and 12 cases, respectively. Two missense mutations, c.599 C>T (T200I) and c.1258 G>A (E420K), were detected in the SIRT1 gene coding region. The SIRT1 and p53 mutation were found in mutually exclusive gastric cancers. The immunohistochemistry revealed that SIRT1 overexpression was found in 95 (55.9%) of 170 gastric cancers. Altered SIRT1 expression was not statistically associated with clinicopathological parameters, including tumor differentiation, location, lymph node metastasis, or p53 expression. Two cases with an SIRT1 mutation showed increased SIRT1 expression. CONCLUSIONS: These results suggest that genetic alterations and overexpression of the SIRT1 gene may contribute to gastric cancer development.

The Expression of Vascular Endothelial Growth Factor (VEGF)-C and VEGF-D in Early Gastric Cancer That's Invaded the Submucosa

PURPOSE: Vascular endothelial growth factor (VEGF)-C and VEGF-D are considered novel growth factors that potentially induce lymphangiogenesis and hyperplasia of lymphatic vessels. The aim of this study was to investigate whether the expressions of VEGF-C and VEGF-D are associated with the clinicophathologic factors, and particularly lymphatic invasion and lymph node metastasis, in early gastric cancers that's invaded the submucosa. METHODS: Using immunohistochemical staining, we studied the VEGF-C and VEGF-D expressions in the gastric cancer specimens from 83 patients who underwent curative gastrectomy. RESULTS: The VEGF-C and VEGF-D immunoreactivity was mainly located in the cytoplasm of the tumor cells. There was a positive VEGF-C expression in 27 of 83 cases (32.5%). The VEGF-D positivity rate was lower than the VEGF-C positivity rate. VEGF-D was positive in 20 of 83 cases (24.0%). A VEGF-C positive expression was associated with lymphatic invasion (P=0.018) and lymph node metastasis (P=0.001). However, the expression of VEGF-D had no correlation with any of the clinicopathologic factors, including lymphatic invasion and lymph node metastasis. CONCLUSION: The VEGF-C expression may have a role in lymph node metastasis of gastric cancer cells. The VEGF-C expression in tumor specimens may be a reliable marker for lymph node metastasis of early gastric cancer that's invaded the submucosa.

An Association of C/T Polymorphism in the TFF1 Gene and the Susceptibility to Gastric Cancer

PURPOSE: This study investigated whether a single nucleotide polymorphism (SNP) located at position -2 in the Kozak sequence of the TFF1 gene is associated with H. pylori infection and the development of gastric cancer in Koreans. MATERIALS AND METHODS: We enrolled 167 patients with gastric cancer from January 2000 to December 2003 and also 299 healthy controls during the same period. The genotype of the TFF1 SNP was analyzed by polymerase chain reaction-restriction fragment length polymorphism and single strand conformation polymorphism. We also examined the H. pylori infection by Giemsa staining. RESULTS: No significant difference in the allele or the TFF1 SNP genotype frequency was observed between the patients with gastric cancer and the control subjects (P=0.595 and P=0.715, respectively). When stratified by the histological subtype of gastric cancer and the age of the patients, the risk was not statistically significant between the two study groups (P=0.088 and P=0.551, respectively). H. pylori infection was detected in 39 cases and it was not associated with the TFF1 genotype. CONCLUSION: These findings suggest that this TFF1 gene polymorphism is not associated with H. pylori infection and gastric cancer in Koreans and so it doesn't contribute to the susceptibility to gastric cancer in Koreans.

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.

Expression Pattern of EphB2 in Gastric Cancer

PURPOSE: The EphB2 receptor, a member of the receptor tyrosine kinase family, is a target gene of the Wnt signaling pathway and may achieve a tumor suppressor function through regulation of cell growth and migration. Our aim was to determine whether an altered expression of EphB2 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, 83 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression patterns of EphB2 were examined on tissue microarray slides by using immunohistochemistry and were compared using pathologic parameters, including histological type, depth of invasion, lymph node metastatsis, and peritoneal dissemination. RESULTS: The EphB2 protein was expressed in the normal gastric mucosal epithelium, especially in the bottom of the mucosa. We found loss of EphB2 expression in 30 (36.1%) of the 83 gastric cancer tissues. Statistically, loss of EphB2 expression was more common in gastric cancer with lymph-node metastasis. There was no significant correlation between EphB2 expression and depth of invasion, histologic type, or peritoneal dissemination. CONCLUSION: Our findings suggest that loss of EphB2 expression may represent a critical step in gastric carcinogenesis.

Mutational Analysis of Caspase-7 and 8 Genes in Non-small Cell Lung Cancer

PURPOSE : Several lines of evidence have indicated that deregulation of apoptosis is involved in the mechanism of cancer development. Caspase-8 activation plays a central role in the initiation phase of apoptosis, while caspase-7 is one of the main execution phase caspases of apoptosis. The aim of this study was to explore the possibility that genetic alterations of the caspase-8 and caspase-7 genes are involved in the development of human non-small cell lung cancer (NSCLC). MATERIALS AND METHODS : We have analyzed the entire coding region of both the caspase-7 and caspase-8 genes to detect the somatic mutations in 100 NSCLCs by using polymerase chain reaction (PCR)- single strand conformation polymorphism (SSCP). RESULTS : The PCR-SSCP analysis detected no mutations in the entire coding regions of both the caspase-7 and caspase-8 genes in the NSCLCs. CONCLUSION : The data presented here suggests that both the caspase-7 and caspase-8 genes may not be somatically mutated in human NSCLCs

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 KLF6 in Korean Gastric Cancers

PURPOSE: KLF6, a member of the KLF family, is a ubiquitous zinc finger tumor suppressor protein that is mutated in several human cancers. Our aim was to determine whether the expression pattern of KLF6 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, 85 paraffin-embedded tissues containing gastric cancer areas were cored 3 times and transferred to the recipient master block. The expression pattern of KLF6 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 KLF6 protein was expressed on superficial and foveolar epithelial cells in the gastric mucosa. We found loss of KLF6 expression in 28 (32.9%) of the 85 gastric cancer tissues. There was a significant correlation between loss of KLF6 expression and lymph-node metastasis. However, other pathologic parameters, such as histologic type, depth of invasion, and peritoneal dissemination, were not statistically associated with loss of KLF6 expression. CONCLUSION: Our findings suggest that loss of KLF6 expression may contribute to abnormal regulation of gastrointestinal epithelial cell growth and differentiation and to the development and/or progression of Korean gastric cancer.

Mutation of the Chk1 Gene in Gastric Cancers with Microsatellite Instability

PURPOSE: The protein kinase Chk1 is required for cell cycle arrest in response to DNA damage and is shown to play an important role in the G2/M checkpoint. The aim of this study was to investigate the relationship between microsatellite instability and frameshift mutation of the Chk1 gene in gastric cancers. MATERIALS AND METHODS: The microsatellite instability was analyzed in 95 primary gastric carcinomas by using microdissection and 6 microsatellite markers. We also performed single strand conformational polymorphism and sequencing to detect frameshift mutation of the Chk1 gene. RESULTS: We found positive microsatellite instability in 19 (20%) of the 95 gastric cancers, 13 high- and 6 low-frequency microsatellite instability cases. The frameshift mutation of Chk1, which resulted in a truncated Chk1 protein, was detected in two high-frequency microsatellite instability cases. CONCLUSION: These data suggest that the microsatellite instability may contribute to the development of gastric carcinomas through inactivation of Chk1.

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.

Promoter Methylation of E-cadherin in Hepatocellular Carcinomas and Dysplastic Nodules

In order to clarify the significance of E-cadherin methylation in multistep hepatocarcinogenesis, we examined the methylation status of the E-cadherin promoter region, using methylation-specific polymerase chain reaction in 64 hepatocellular carcinomas (HCCs) and 13 dysplastic nodules (DNs), and correlated these results with E-cadherin protein expression and clinicopathologic factors of HCCs. Promoter methylation was detected in 1 of 13 (7.7%) DNs, in 5 of 13 (38.5%) Edmondson and Steiner grade I HCCs, and in 27 of 51 (52.9%) grade II or III HCCs, and a significant correlation was observed between the methylation status and the stepwise progression of hepatocarcinogenesis (p=0.004). Reduced E-cadherin immunoreactivity was found in 18 of 64 (28%) HCCs, but in none of DNs. E-cadherin methylation status in HCCs was significantly correlated with microvascular invasion (p=0.02) and tumor recurrence (p=0.04), but not with reduced E-cadherin immunoreactivity. The Kaplan-Meier method showed that methylation status did not have a significant influence on the recurrence-free survival of HCC patients (p=0.15). Our results indicate that methylation of the E-cadherin promoter region is a frequent event in HCC, which may play an important role in the stepwise progression of hepatocarcinogenesis. And the promoter methylation of E-cadherin in HCC was found to be significantly correlated with microvascular invasion and recurrence.

Mutational Analysis of Proapoptotic bcl-2 Family genes in Colon Carcinomas

BACKGROUND: Several lines of evidence have indicated that the deregulation of apoptosis is involved in the mechanisms of cancer development, and somatic mutations of the apoptosisrelated genes have been reported in human cancers. Members of the bcl-2 family proteins regulate the intrinsic apoptosis pathway mainly in the mitochondria. The aim of this study was to explore whether the somatic mutation of the proapoptotic bcl-2 family genes, one of the mechanisms that prolong the survival of cancer cells, occurred in colorectal carcinomas. METHODS: In the current study, to detect the somatic mutations in the DNA sequences encoding the bcl-2 homology 3 (BH3) domain of the human bak, bid, bik, bim, PUMA, bcl-rambo, bcl-G, and bmf genes in 98 colon adenocarcinomas, we used polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP), and DNA sequencing. RESULTS: The SSCP analysis detected no evidence of somatic mutations of the genes in the coding regions of the BH3 domain in the cancers. CONCLUSIONS: The data presented here indicate that the proapoptotic bcl-2 family genes, bak, bid, bik, bim, PUMA, bcl-rambo, bcl-G and bmf may not be somatically mutated in human colorectal carcinomas, and suggest that the colorectal cancers may not utilize mutational events of these proapoptotic bcl-2 family genes in the mechanisms for evading apoptosis.