Methylation analysis of Rb, P16, MGMT, and hMLH-1in mucoepidermoid carcinomas. A pilot study

Mucoepidermoid carcinoma (MC) is the most common malignant epithelial neoplasm in the salivary glands. This neoplasm has varying proportions of mucous, epidermoid, intermediate, columnar, and clear cells. MCs have been associated with CRTC1-MAML2 genes; however, their pathogenesis is uncertain. Recently, epigenetic changes have been considered a possible aetiologic factor. To identify the methylation state of RB, P16, MGMT, and hMLH genes in the three severity grades of MC were used five MCs and one healthy minor salivary gland as a control group (CG) obtained from the Pathology and Oral Medicine Laboratory and analyzed using MS-PCR to compare the presence or absence of methylation in promotor regions. The Kruskal- Wallis test was performed, with p≤0.05 considered significant. CG was employed as the normalizer of methylation levels. All assays were performed in triplicate. The mean age of our population was 52.6±18.6 years old; the total population was female and included 2 low grade, 2 intermediate grade, and 1 high grade levels of severity. When comparing the methylation status of the three histopathological grades of MC against the control, statistically significant differences were observed in Rb-M, MGMT-M, and hMLH-1-NM for high-grade severity, with p values of 0.03, 0.05, and 0.04, respectively. Methylation is a possible mechanism for pathogenesis processing of high-grade MC. However, a larger sample population is necessary to validate this finding.

El carcinoma mucoepidermoide (CM) es la neoplasia epitelial maligna más frecuente de glándulas salivales. Esta neoplasia tiene proporciones variables de células mucosas, epidermoides, intermedias, cilíndricas y claras. Los CM se han asociado con los genes CRTC1-MAML2; sin embargo, su patogenia es incierta. Recientemente, los cambios epigenéticos se han considerado un posible factor etiológico. Para identificar el estado de metilación de los genes RB, P16, MGMT y hMLH en los tres grados de severidad de CM se utilizaron cinco CM y una glándula salival menor sana como grupo control (GC) obtenidos del Laboratorio de Patología y Medicina Oral y analizados mediante MS-PCR para comparar la presencia o ausencia de metilación en regiones promotoras. Se realizó la prueba de Kruskal-Wallis, considerándose significativa una p≤0,05. Se empleó GC como normalizador de los niveles de metilación. Todos los ensayos se realizaron por triplicado. La edad media de nuestra población fue de 52,6 ± 18,6 años; la población total era femenina e incluía 2 niveles de severidad de grado bajo, 2 de grado intermedio y 1 de alto grado. Al comparar el estado de metilación de los tres grados histopatológicos de CM contra el GC, se observaron diferencias estadísticamente significativas en Rb-M, MGMT-M y hMLH-1-NM para severidad de alto grado, con valores de p de 0.03, 0.05, y 0,04, respectivamente. La metilación es un posible mecanismo para el procesamiento de patogénesis de CM de alto grado. Sin embargo, se necesita una población de muestra más grande para validar este hallazgo.

Relevance of hMLH1 -93G>A, 655A>G and 1151T>A polymorphisms with colorectal cancer susceptibility: a meta-analysis based on 38 case-control studies

SUMMARY OBJECTIVE: There has been increasing interest in the study of the association between human mutL homolog 1 (hMLH1) gene polymorphisms and risk of colorectal cancer (CRC). However, results from previous studies are inconclusive. Thus, a meta-analysis was conducted to derive a more precise estimation of the effects of this gene. METHODS: A comprehensive search was conducted in the PubMed, EMBASE, Chinese Biomedical Literature databases until January 1, 2018. Odds ratio (OR) with 95% confidence interval (CI) was used to assess the strength of the association. RESULTS: Finally, 38 case-control studies in 32 publications were identified met our inclusion criteria. There were 14 studies with 20668 cases and 19533 controls on hMLH1 −93G>A, 11 studies with 5,786 cases and 8,867 controls on 655A>G and 5 studies with 1409 cases and 1637 controls on 1151T>A polymorphism. The combined results showed that 655A>G and 1151T>A polymorphisms were significantly associated with CRC risk, whereas −93G>A polymorphism was not significantly associated with CRC risk. As for ethnicity, −93G>A and 655A>G polymorphisms were associated with increased risk of CRC among Asians, but not among Caucasians. More interestingly, subgroup analysis indicated that 655A>G might raise CRC risk in PCR-RFLP and HB subgroups. CONCLUSION: Inconsistent with previous meta-analyses, this meta-analysis shows that the hMLH1 655A>G and 1151T>A polymorphisms might be risk factors for CRC. Moreover, the −93G>A polymorphism is associated with the susceptibility of CRC in Asian population.

RESUMO OBJETIVO: Tem havido crescente interesse no estudo da associação entre polimorfismos do gene mutL homólogo 1 humano (hMLH1) e risco de câncer colorretal (CRC). No entanto, os resultados de estudos anteriores não são conclusivos. Assim, uma meta-análise foi conduzida para obter uma estimativa mais precisa dos efeitos desse gene. MÉTODOS: Uma pesquisa abrangente foi realizada nas bases de dados PubMed, Embase, Chinese Biomedical Literature até 10 de janeiro de 2018. Odds ratio (OR) com 95% de intervalo de confiança (IC) foi utilizado para avaliar a força da associação. RESULTADOS: Finalmente, foram identificados 38 estudos de casos e controles em 32 publicações, atendendo aos nossos critérios de inclusão. Houve 14 estudos com 20.668 casos e 19.533 controles em hMLH1 −93G>A, 11 estudos com 5.786 casos e 8.867 controles em 655A>G e cinco estudos com 1.409 casos e 1.637 controles em 1151T>Um polimorfismo. Os resultados combinados mostraram que os polimorfismos 655A>G e 1151T>A estavam significativamente associados ao risco de CRC, enquanto que o polimorfismo −93G>A não estava significativamente associado ao risco de CRC. Quanto à etnia, os polimorfismos de −93G>A e 655A>G foram associados ao risco aumentado de CRC entre os asiáticos, mas não entre os caucasianos. Mais interessante, a análise de subgrupos indicou que 655A>G pode aumentar o risco de CRC em subgrupos PCR-RFLP e HB. CONCLUSÃO: Inconsistente com a meta-análise anterior, esta meta-análise mostra que os polimorfismos hMLH1 655A>G e 1151T>A podem ser fatores de risco para CRC. Além disso, o polimorfismo −93G>A está associado à susceptibilidade do CRC na população asiática.

Correlation between promoter methylation of hMLH1 and DAPK genes and drug resistance of lung cancer / 肿瘤研究与临床

Drug resistance is one of the major obstacles for chemotherapy and targeted therapy in lung cancer with complex mechanisms.The researches have demonstrated that epigenetic changes are closely related to drug resistance of tumor.DNA methylation is an important epigenetic modification.In this paper, the relationships between hMLH1 promoter aberrant methylation and platinum-resistance, and DAPK promoter aberrant methylation and EGFR-TKI resistance in lung cancer will be briefly reviewed.

Effects of 5-Aza-Cde on DNA Methylation and Expression of hMLHl and MGMT Gene in Lung Cancer Cell Line A549/DDP / 现代检验医学杂志

Objective To investigate the effects of 5-Aza-2′-deoxycytidine (5-Aza-Cde)on DNA methylation and expression of hMLH1 and MGMT gene in the human lung cancer cell line A549/DDP.Methods A549/DDP cells were cultured with RPMI 1 640 medium and were treated with 5 μmol/L DNA methyhransferase inhibitor 5-Aza-Cde.Methylation-specific pol-ymerase chain reaetioll (MSP)was used to detect the promoter methylation state of the hMLH1 and MGMT gene.RT-PCR was used to detect the mRNA expression of hMLH1 and MGMT before and after treatment with 5-Aza-Cde,respectively. Results Before treatment with 5-Aza-Cde,hMLH1 and MGMT expressions were absent,and promoter hypermethylation of the hMLH1 and MGMT gene were detected in A549 cells.After treatment with 5-Aza-Cde,the promoter region of the hM-LH1 and MGMT gene exhibited a demethylation state,and their mRNA expressions were increased.Conclusion Promoter hypermethyhtion is amajor mechanism of hMLH1 and MGMT gene silencing in human lung cancer cells,and can be reversed by the demethylating agent 5-Aza-Cde,which can regulate the expressions of the hMLH1 and MGMT gene.

Effects of 5-Aza-CdR on cell apoptosis in lung cancer A549/DDP cell line and expression of tumor suppressor gene hMLH1 / 肿瘤研究与临床

Objective To investigate the effects of 5-Aza-2'-deoxycytidine (5-Aza-CdR) on the apoptosis of A549/DDP cells and the expression of hMLH1 gene.Methods A549/DDP cells were treated with 5-Aza-CdR at 0.5,5,50 μmol/L.The growth curve of A549/DDP cells was investigated by MTT assay.The methylation status of hMLH1 gene was detected by methylation specific PCR (MSP).The expression of hMLH1 mRNA was evaluated by FQ-PCR.The apoptosis rate of A549/DDP cells was analyzed by flow cytometry.Results A549/DDP cells treated with 5-Aza-CdR showed a slow growth in comparison with the control cells,and the growth rates were decreased with the increasing of 5-Aza-CdR concentration.The apoptosis rate after treatment was higher than that before treatment in A549/DDP cells (P ＜ 0.05),and had a positive correlation with 5-Aza-CdR dose (P ＜ 0.001).hMLH1 mRNA expression level was increased in a 5-Aza-CdR concentration dependent manner (P ＜ 0.05).hMLH1 promoter in A549/DDP cells was methylated and hMLH1 mRNA was negatively expressed before treatment,but the mRNA was positively expressed after treatment with 5-Aza-CdR.Conclusions 5-Aza-2'-CdR can induce apoptosis of A549/DDP cells by inducing demethylation of hMLH1 promoter and thereby enhancing hMLH1 gene expression and its tumor suppressor function.

Expression and clinical significance of hMLH-1 and hMSH-2 in Han and Uygur in Xinjiang area of sporadic colorectal carcinoma / 临床与实验病理学杂志

Purpose To detect the incidence rate, average age and the expression of hMLH-1 and hMSH-2 of sporadic colorectal carci-noma ( SCC) with Han and Uygur patients. Methods The expression of hMLH-1 and hMSH-2 was detected in SCC for 60 cases of Uygur and 196 cases of Han by immunohistochemical method, including 60 Uygur and Han cases normal colorectal mucosa ( NCM) . Results The positive rate of hMLH-1 and hMSH-2 proteins expression in the NCM was 100%. There was a marked difference in the positive rate of hMLH-1 in SCC between Han (93. 4%, 183/196)and Uygur (75%, 45/60) (P0. 05). The average age of Han and Uygur SCC patients were 65. 64 years, 57. 63 years, respectively, and Uygur SCC cases were more likely to be diagnosed at less 40 years old (P<0. 05). The positive rate of hMLH-1 and hMSH-2 expression in the tubular adenoma was 100%. The positive rate of hMLH-1 and hMSH-2 expression in the tubulovillous adenoma in Uygur and Han were 66. 7%( 2/3 ) and 66. 7%( 2/3 ) , and 74. 2%(23/31) and 90. 3%(28/31), respectively, significantly lower than those of tubular adenoma (P<0. 05). The expression of hMLH-1 was positively correlated with that of hMSH-2 in SCC in Han(rs =0. 737, P<0. 05). The expression of hMLH-1 was positive-ly correlated with that of hMSH-2 in SCC in Uygur(rs =0. 383, P<0. 05). There exists marked difference in the positive rate of hM-LH-1 and hMSH-2 among difference age groups (P<0. 05). Conclusion There is a certain loss of hMLH-1 and hMSH-2 expression in SCC in Han and Uygur Chinese, which is related to adenoma and age. The expression of hMLH-1 in SCC tissue among Uygur pa-tients is not resemble to those of Han patients. The average age of Uygur SCC patients is younger than Han, and the positive rate of hMLH-1 is higher. Combined detection of hMLH-1 and hMSH-2 proteins may be used for judging the severity and prognosis of SCC in Xinjiang, which helps improve patients’ treatment program and rationalize their choices.

Research on Reprimo,hMLH1 Gene Methylation in Early Diagnosis Value of Gastric Cancer / 现代检验医学杂志

Objective To investigate the Reprimo and hMLH1 gene promoter methylation detection value in the diagnosis of early gastric cancer.Methods Chose patints in Shaanxi Provincial People’s Hospital from September 2013 to April 2014,50 cases of patients with chronic atrophicgastritis with intestinal metaplasia,50 cases of patients with gastricmucosal atypical hyperplasia,50 patients with gastric cancer,endoscopic gastric biopsy samples,and 30 cases of normal gastric mucosa biopsy tissues as control group.Analysis abnormal expression in Reprimo gene and hMLH1 genes promoter methylation,compared the differences.between groups of patients.Results The patients with gastric mucosatissues Reprimo and hMLH1 genes promoter methylation positive rate was significantly higher than that of normal group,the difference wasstatistically signifi-cant (P<0.05).Reprimo gene promoter methylation were:patients with chronic atrophic gastritis with intestinal metaplasia 28% (χ2 =10.18,P < 0.05).Patients with gastric mucosalatypical hyperplasia 56% (χ2 = 25.84,P < 0.05)and patients with gastric cancer 62% (χ2 = 30.36,P < 0.05).hMLH1 gene promoter methylation were:patients with chronic atrophic gastritis with intestinal metaplasia 20% (χ2 =4.39,P <0.05),patients with gastric mucosal atypical hyperplasia 44% (χ2 =15.13,P <0.05)and patients with gastric cancer 48% (χ2 = 17.41,P <0.05),high specificity of detection.Conclusion Reprimo and hMLH1 gene’s detect value in the diagnosis of early gastric cancer is very high,high specificity,it is an effec-tive way of diagnosis,treatment in clinical diagnosis of patients with broad prospects.

Usefulness of Immunohistochemistry for Microsatellite Instability Screening in Gastric Cancer

BACKGROUND/AIMS: The usefulness of immunohistochemistry to screen for the microsatellite instability (MSI) phenotype in gastric cancer remains unclear. Moreover, the prognostic value of MSI phenotypes in gastric cancer has been debated. METHODS: The clinicopathologic parameters and survival outcomes of 203 MSI-high (MSI-H) and 261 microsatellite-stable (MSS) advanced gastric cancers (AGCs) were compared. Next, we compared the immunohistochemistry results for hMLH1 and hMSH2 with those of a polymerase chain reaction (PCR)-based method. Kaplan-Meier curves and a Cox proportional hazard regression model were used to conduct survival analyses. RESULTS: The MSI-H AGCs were correlated with older age (p<0.001), female gender (p=0.018), distal location (p<0.001), larger size (p=0.016), and intestinal type (p<0.001). Multivariate analysis revealed that the MSI-H phenotype was an independent favorable factor that was related to overall survival in patients with AGC (p<0.001). Compared with the PCR-based analysis, immunohistochemistry exhibited high sensitivity (91.1%) and specificity (98.5%) in the detection of MSI phenotypes. CONCLUSIONS: MSI-H gastric cancers have distinct clinicopathologic features and better prognoses, which suggests the necessity of MSI analysis in gastric cancer. Immunohistochemistry can be a useful and reliable screening method in the assessment of MSI status in gastric cancer.

Effects of Gossypol Acetic Acid on Protein and mRNA Expressions of hMLH1 Gene in Human Tongue Carcinoma Cell Line Tca8113 / 昆明医科大学学报

Objective The purpose of this study was to investigate the effects of gossypol acetic acid (GAA) on protein and mRNA expressions of hMLH1 gene in human tongue carcinoma cell line Tca8113 in vitro in order to discuss the mechanism of tumor suppression of GAA. Methods (1) Western-blot was used to study the effects of GAA on protein expressions of hMLH1 gene in Tca8113 cell line treated by different concentrations of GAA for 48 h. (2) Real-time fluorescence quantitative PCR (RFQ-PCR) was used to investigate the effects on the mRNA expressions of hMLH1 gene in Tca8113 cell line treated by GAA for 48 h. Results (1) Compared with the control group, the results of Western-blot showed that the protein expression of hMLH1 gene was increased after treatment by GAA for 48 h ( <0.05) . (2) The results of RFQ-PCR indicated that the mRNA expression of hMLH1 gene was increased after GAA treatment for 48 h ( <0.05) . Conclusion GAA could up-regulate protein and mRNA expression of hMLH1 in Tca8113 cell line, which indicated that it may be one of the mechanisms of tumor suppression effect of GAA.

Expression of hMLH1 and hMSH2 in suspected hereditary non-polyposis colorectal cancer / 实用医学杂志

Objective To analyse the suspected hereditary non-polyposis colorectal cancer (HNPCC) in mismatch repair protein (MMR) expression of hMLH1 and hMSH2. Methods Immunohistochemical staining method was used for the detection of hMLH1 and hMSH2 protein expression in 193 cases suspected HNPCC patients, the deletion of MMR proteins was identified as highly suspected HNPCC cases. Results Of the 193 patients with suspected HNPCC hMLH1/hMSH2 abnormal expression rate was 29.02%; ≤30 years old was 40%, 31 ~ 40 years old was 28.05%, 41 ~ 50 years old was 28.71%,3 suspected HNPCC showed the deletion of hMLH1/hMSH2 protein expression at the same time ,; In the right colon , the left half colon and rectal anomaly detection rates were 40.74%, 32.65%and 18.89%; hMLH1/hMSH2 deletion was 46.15%with family history. Conclusions The deletion of MMR protein is closely related to age,site and family history in suspected HNPCC, and the deletion of hMLH1 is an important factor to induce early-set colorectal cancer. The deletion of hMLH1/hMSH2 at the same time indicates that hMLH1/hMSH2 genes may play important role in the incidence of HNPCC.

hMLH1 promoter methylation and BRAF mutations in high-frequency microsatellite instability colorectal cancers not fulfilling the revised Bethesda guidelines

PURPOSE: Sporadic colorectal cancers with high-frequency microsatellite instability (MSI-H) are related to hypermethylation of mismatch repair (MMR) genes and a higher frequency of BRAF mutations than Lynch syndrome. We estimated the feasibility of hereditary colorectal cancer based on hMLH1 methylation and BRAF mutations. METHODS: Between May 2005 and June 2011, we enrolled all 33 analyzed patients with MSI-H cancer (male:female, 23:10; mean age, 65.5 +/- 9.4 years) from a prospectively maintained database that didn't match Bethesda guidelines and who had results of hMLH1 methylation and BRAF mutations. RESULTS: Among the 33 patients, hMLH1 promoter methylation was observed in 36.4% (n = 12), and was not significantly related with clinicopathologic variables, including MLH1 expression. BRAF mutations were observed in 33.3% of the patients (n = 11). Four of 11 and five of 22 patients with MSI-H colon cancers were BRAF mutation (+)/hMLH1 promoter methylation (-) or BRAF mutation (-)/hMLH1 promoter methylation (+). Of the 33 patients, 21.2% were BRAF mutation (+)/hMLH1 promoter methylation (+), indicating sporadic cancers. Seventeen patients (51.5%) were BRAF mutation (-)/hMLH1 promoter methylation (-), and suggested Lynch syndrome. CONCLUSION: Patients with MSI-H colorectal cancers not fulfilling the Bethesda guidelines possibly have hereditary colorectal cancers. Adding tests of hMLH1 promoter methylation and BRAF mutations can be useful to distinguish them from sporadic colorectal cancers.

Expression of mismatch repair genes hMLH1 and hMSH2 and their significance in patients with colorectal carcinoma / 中国肿瘤临床

10.3969/j.issn.1000-8179.2013.12.007

The correlation among hMLH1, NIS and TSHR genes with promoter methylation in papillary thyroid carcinoma and its clinical significance / 肿瘤

Objective: To investigate the aberrant methylation status of hMLH1 (human mutL homologue 1) gene in PTC (papillary thyroid carcinoma) tissues, and its correlations with the aberrant methylation of NIS (sodium iodide symporter) and TSHR (thyroid-stimulating hormone receptor) genes. Methods: qMSP (quantitative methylation-specific PCR) was carried out to detect the promoter methylation status of hMLH1, NIS and TSHR genes in PTC tissues and adjacent normal thyroid tissues from 152 patinets with PTC. The correlation between the clinicopathologic characteristics and the promoter methylation status of hMLH1 gene was analyzed. The relationships among the methylation status of hMLH1, NIS and TSHR genes and their independent or synergistic effects on the progression of PTC were investigated. Results: The promoter methylation rate of hMLH1 gene in PTC tissues (37.5%) was significantly higher than that in the adjacent normal thyroid tissues (5.3%) (P 0.05). There was a weak correlation among aberran promoter methylation of hMLH1, NIS and TSHR genes (r 0.05). Conclusion: The aberrant methylation of hMLH1 gene promoter in PTC tissues might be associated with the progression of the tumor. There exists no correlation among the aberrant methylation of hMLH1, NIS and TSHR genes, and their independent or synergistic effect also may not be associated with the progression of PTC. Copyright © 2013 by TUMOR.

Implication of DNA repair genes in prostate tumourigenesis in Indian males.

Background & objectives: Prostate cancer (CaP) is the fifth most common cancer among Indian men. Tumour protein p53 (TP53) gene increases the fidelity of DNA replication and homologous recombination by transcriptional transactivation of mismatch repair (MMR) genes. DNA repair thus has a potential role in molecular carcinogenesis of CaP. The aim of the present study was to identify mutations, and polymorphisms in TP53 gene and MMR protein expression in CaP in Indian male population. Methods: TP53 codon 72 polymorphism was analysed in 105 CaP, 120 benign prostatic hyperplasia (BPH) cases and 106 normal controls. Mutational analysis of TP53 was done in DNA extracted from formalin fixed paraffin embedded tissue of 80 CaP and 24 BPH cases. Expression of MMR proteins viz. hMLH1, hMSH2, hPMS1 and hPMS2 was studied in 80 CaP, 15 prostatic intraepithelial neoplasia (PIN) and 15 BPH cases. Results: A somatic C/A variation at the intronic boundary of exon 7 in TP53 gene was observed in one each biopsy samples from CaP and BPH. A significant association of codon 72 TP53 Pro/Pro genotype was observed with the risk of CaP (OR, 2.59, P=0.02) and BPH (OR, 6.27, P<0.001). Immunohistochemical analysis of MMR proteins showed maximum loss of hPMS1 expression in cases of CaP and PIN while no loss in expression of MMR proteins was observed in BPH cases. The study also identified a significant loss of hPMS2 protein in poorly differentiated tumours (Gleason score >7) than in well differentiated tumours (Gleason score 3-6) (P<0.05). Interpretation & conclusions: The results of the present study demonstrate that TP53 codon 72 polymorphism plays significant role in the pathogenesis and susceptibility to CaP and BPH. Also, an aberrant MMR protein expression could be involved in progression of prostate cancer through PIN, early CaP to aggressive CaP. The loss of hPMS2 protein expression may serve as a marker for progression of CaP.

Overexpression of p53, Mutation of hMLH1 and Microsatellite Instability in Gastric Carcinomas: Clinicopathologic Implications and Prognosis

PURPOSE: Mutated p53 is a tumor suppressor gene, hMLH1 is a mismatch repair gene, and hypermethylation of hMLH1 follows microsatellite instability (MSI). This research's aim is to investigate mutated p53, inactivated hMLH1 and MSI in gastric cancer and their clinicopathologic implications. METHODS: Between 2003 and 2007, 618 patients underwent curative radical gastrectomy for gastric cancer at Seoul National University Bundang Hospital in Korea. We reviewed their medical charts and the pathologic reports with immunohistochemistry for p53, hMLH1 and polymerase chain reaction for MSI in 509, 499, and 561 cases, respectively. These genetic markers were statistically compared with clinicopathologic features and postoperative survival. RESULTS: The expression ratios of mutated p53, inactivated hMLH1, and MSI were 32.8%, 8.4%, and 8.7%, respectively. Mutation of p53 occurred more frequently in aged group (over 40), differentiated group (against the non-differentiated group), intestinal type, infiltrative type and positive lymph node metastasis group. Inactivated hMLH1 occurred more frequently in aged group, differentiated group, intestinal type and expanding growth type group. MSI was found more frequently in aged group, intestinal type and expanding growth type group. All three genetic markers had no significant associations with the 5-year survival. CONCLUSION: We identified significant relationships between mutated p53, inactivated hMLH1, and MSI with some clinicopathologic features of gastric cancer. However, there were no apparent relationships between p53, hMLH1, and MSI and prognosis.

Expression of hMLH1 and hMSH2 in hilar cholangiocarcinoma and its significance / 中华肝胆外科杂志

Objective To investigate the expression of hMLH1 and hMSH2 in hilar cholangiocarcinoma and its relation to clinical features and prognosis of the tumor.Methods The expression of hMLH1 and hMSH2 was determined with immunohistochemistry in 54 specimens of hilar cholangiocarcinoma and 25 of normal bile duct tissue.Lahoratory data were then analyzed statistically together with the related clinicopathological data.Results 1)hMLH1 and hMSH2 were expressed in 24 and 21 out of the 54 cases of hilar cholangiocarcinoma(44.4%,38.9%)and 23 and 21 of the 25 normal cases(92%,84%),respectively(P＜0.05).2)The expression of hMLH1 and hMSH2 in hilar cholangiocarcinoma had no association with the age,gender,tumor size and Bismuth type(P＞0.05)but close relation to lymph node metastasis and pathological changes(P＜0.05).3)The 2-year survival rate was markedly lower in hMLH1-negative patients than in hMLH1-and hMSH2-positive ones (15%vs.45.4%,23.5%vs.44%,P＜0.05).Conclusions Joint action of hMLH1 and hMSH2plays an important role in the oncogenesis and metastasis of hilar cholangiocarcinoma.These two may be valuble factors to indicate prognosis of the tumor.

Genetic Expression Pattern of Gastric Carcinomas According to Cellular Mucin Phenotypes

BACKGROUND: Gastric carcinomas (GCs) have recently been reclassified according to the mucin phenotypes. We aimed to characterize the relationship between the mucin phenotypes and the genetic alterations or the clinicopathologic parameters of GCs. METHODS: Immunohistochemistry was performed for MUC1, MUC5AC, MUC6, MUC2, CD10, p53, hMLH1, CerbB2 and E-cadherin in 150 GCs. The mucin phenotypes of the GCs were classified as 4 phenotypes: gastric, intestinal, mixed and unclassified. RESULTS: MUC1, MUC5AC, MUC6, MUC2 and CD10 were expressed in 63.3%, 42.7%, 14.0%, 24.7% and 14.0% of the GCs, respectively. The mucin phenotypes of the GCs corresponded to the gastric type in 31.3%, the intestinal type in 20.0%, the mixed type in 15.3% and the unclassified type in 33.3%. The incidence of a p53 overexpression was higher in the gastric or mixed phenotype than in the intestinal or unclassified phenotype. MUC5AC expression, p53 overexpression and the gastric or mixed phenotype were associated with poor patient survival by multivariate analysis. CONCLUSION: This study suggests the gastric or mixed mucin phenotype may more likely go through the p53 pathway in carcinogenesis and the mucin phenotype may be considered as a prognostic indicator.

Analysis of Microsatellite Instability in Ovarian Epithelial Cancer

BACKGROUND: The aim of this study was to clarify the incidence and role of microsatellite instability (MSI) in sporadic ovarian epithelial cancers (OEC). We investigated the MSI status and mismatch repair (MMR) protein expression in OEC. METHODS: MSI was examined by fluorescence- based polymerase chain reaction using five NCI panel markers (BAT25, BAT26, D2S123, D5S346 and D17S250) in 46 cases of OEC. Immunohistochemistry (IHC) for hMLH1 and hMSH2 was performed. RESULTS: Seven cases (15.2%) exhibited high-frequency MSI (MSIH), one exhibited low-frequency MSI (MSI-L), and the remaining 38 demonstrated microsatellite stability (MSS). MSI-H in OEC was not associated with histologic grade, FIGO stage, tumor size, mitoses or histologic type. Loss of expression of either hMLH1 or hMSH2 was observed in 4 of the 7 (59.3%) MSI-H cases, whereas 4 of the 39 (10.3%) MSI-L or MSS tumors revealed loss of expression of MMR proteins. The sensitivity and specificity of immunohistochemistry for hMLH1 and hMSH2 were 57.1% and 89.7%. CONCLUSIONS: Our data suggest that a genetic defect in the MMR system might play a role in the carcinogenesis of a minor subset of sporadic OEC however, immunohistochemical testing for hMLH1 and hMSH2 cannot accurately determine microsatellite instability status in OEC.

Expression of beta-catenin, hMLH1, p53, Bcl-2, Bax and COX-2 in Serrated Adenomas of Colon / 대한소화기내시경학회지

BACKGROUND/AIMS: Serrated adenoma of the colorectum is a recently proposed entity that is characterized by a saw-toothed structure of hyperplastic polyp and also the cytologic atypia of conventional adenoma. In contrast to conventional adenomas, the molecular features of serrated adenomas have been poorly studied. METHODS: The expression of beta-catenin and the DNA mismatch repair protein hMLH1, apoptosis regulating protein Bcl-2, Bax, p53 and COX-2 were analyzed in 28 serrated adenoma specimens and 28 tubular adenoma specimens. RESULTS: No differences were observed in the frequency of beta-catenin loss in the cell membrane between the serrated and tubular adenoma specimens. The frequency of hMLH1 loss was significantly higher in the serrated adenomas than in tubular adenomas (p 60 years old). In the tubular adenoma specimens, the frequency of p53 overexpression was increased in the dysplastic epithelium. CONCLUSIONS: The expressions of hMLH1, Bax and Bcl-2 were decreased in the serrated adenoma than in the tubular adenoma. Our data suggest that the serrated adenoma and tubular adenoma may have different pathway in their development. However, further studies including normal mucosa, hyperplastic polyp and cancer specimens are needed.

Expression of hMLH_1 gene in gastric cancer and its significance / 吉林大学学报(医学版)

Objective To investigate the expression of hMLH_1 in gastric cancer and its significance,Methods The expressions of hMLH_1 protein and mRNA were detected by immunohistochemistry and reverse transcription polymerase chain reaction(RT-PCR) in 68 cases of gastric cancer tissues,33 cases of para-cancer tissues and(35 cases) of normal gastric tissues.Apoptosis was assayed by terminal deoxytransferase mediated dUTP nicked labeling.Results The positive expression rates of hMLH_1 mRNA were 63.3%(43/68),100%(33/33) and 100%(35/35),and those of protein were 61.8%(42/68),93.9%(31/33),100%(35/35),respectively,in gastric cancer tissues,para-cancer tissues and normal gastric tissues.There was a correlation between the expression of hMLH_1 and clinical grade of gastric cancer(r=0.531,P