OBJECTIVE: Recent investigations have revealed DNA mismatch repair (MMR) gene mutations are closely related with carcinogenesis of endometrial cancer; however the impact of MMR protein expression on prognosis is not determined. Correlations between MMR-related protein expression and clinicopathological factors of endometrial cancers are analyzed in the present study. METHODS: A total of 191 endometrial cancer tissues treated between 1990 and 2007 in our hospital were enrolled. Immunoreactions for MSH2, MLH1, MSH6, and PMS2 on tissue microarray specimens and clinicopathological features were analyzed retrospectively. RESULTS: Seventy-six cases (40%) had at least one immunohistochemical alteration in MMR proteins (MMR-deficient group). There were statistically significant differences of histology, International Federation of Gynecology and Obstetrics (FIGO) stage, and histological grade between MMR-deficient group and the other cases (MMR-retained group). Response rate of first-line chemotherapy in evaluable cases was slightly higher in MMR-deficient cases (67% vs. 44%, p=0.34). MMR-deficient cases had significantly better progression-free and overall survival (OS) compared with MMR-retained cases. Multivariate analysis revealed MMR status was an independent prognostic factor for OS in endometrial cancers. CONCLUSION: MMR-related proteins expression was identified as an independent prognostic factor for OS, suggesting that MMR was a key biomarker for further investigations of endometrial cancers.
Adaptor Proteins, Signal Transducing/deficiency/metabolism ; Adenosine Triphosphatases/deficiency/metabolism ; Adult ; Aged ; Aged, 80 and over ; Chemotherapy, Adjuvant ; *DNA Mismatch Repair ; DNA Repair Enzymes/deficiency/*metabolism ; DNA-Binding Proteins/deficiency/*metabolism ; Endometrial Neoplasms/*diagnosis/drug therapy/genetics/pathology ; Female ; Humans ; Kaplan-Meier Estimate ; Middle Aged ; MutS Homolog 2 Protein/deficiency/metabolism ; Neoplasm Proteins/deficiency/metabolism ; Nuclear Proteins/deficiency/metabolism ; Prognosis ; Retrospective Studies ; Tumor Markers, Biological/*metabolism

OBJECTIVETo explore the relationship between DNA mismatch repair (MMR) and clinicopathologic features and prognosis in patients with stages II and III colon cancers.

METHODSThe clinical and pathological data of 440 patients with stage II/III colon cancer after radical resection were retrospectively reviewed and analyzed. Immunohistochemical staining was used to assess the expression of MMR proteins (MLH1, MSH2, MSH6 and PMS2), and the correlation between DNA MMR and clinicopathological features and prognosis of colon cancers was analyzed.

RESULTSOf the 440 tumor samples tested for DNA mismatch repair status, 90 (20.5%) demonstrated defective DNA mismatch repair and 350 (79.5%) had proficient DNA mismatch repair. Defective DNA mismatch repair (dMMR) was associated with young patients (≤ 60), proximal colon cancer, stage II, poorly differentiated adenocarcinoma and mucinous adenocarcinoma (P<0.05 for all). Among the 440 patients, 126 (28.6%) cases had recurrence or metastasis and 93 (21.1%) died during the median follow-up of 61.0 months. The five-year disease-free survival (DFS) rate was 82.2% among the patients with tumor exhibiting dMMR, significantly higher than that in patients with tumors exhibiting pMMR (68.9%, P=0.02). The univariate and mutlivariate analyses showed that the MMR status is an independent factor affecting 5-year disease-free survival and overall survival (OS) in colon cancer patients (P<0.05 for both).

CONCLUSIONSDefective DNA mismatch repair (dMMR) is associated with patients with proximal colon cancer, stage II and poorly defferentiated adenocarcinoma and mucinous adenocarcinoma. The prognosis for patients with dMMR is better than those with pMMR. dMMR may be a useful biomarker for the prognosis of colon cancer.

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma ; genetics ; metabolism ; mortality ; pathology ; Adenocarcinoma, Mucinous ; genetics ; metabolism ; mortality ; pathology ; Adenosine Triphosphatases ; metabolism ; Age Factors ; Analysis of Variance ; Colonic Neoplasms ; genetics ; metabolism ; mortality ; pathology ; DNA Mismatch Repair ; DNA Repair Enzymes ; metabolism ; DNA-Binding Proteins ; metabolism ; Disease-Free Survival ; Humans ; Mismatch Repair Endonuclease PMS2 ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Neoplasm Recurrence, Local ; Nuclear Proteins ; metabolism ; Prognosis ; Retrospective Studies ; Survival Rate

OBJECTIVETo analyze immunophenotypes and gene mutations of colorectal precancerous lesions and adenocarcinoma, and to compare the difference of carcinogenetic mechanisms between the two precancerous lesions.

METHODSFifty-three cases of colorectal serrated lesions including 30 hyperplastic polyps, 20 sessile serrated adenomas (SSA) and 3 mixed polyps were collected from January 2006 to June 2012.Forty-five cases of traditional adenomas and 50 cases of colorectal adenocarcinomas were also recruited. Thirty hyperplastic polyps, 20 cases of SSA, 3 mixed polyps and 45 traditional adenomas were investigated by immunohistochemistry for the expression of DNA mismatch repair (MMR) proteins (MLH1, MSH2 and MSH6) and DNA methyltransferase MGMT. Mutations of KRAS, BRAF and PIK3CA genes in 10 cases of SSAs, 10 traditional adenomas, 1 mixed polyps and 50 colorectal adenocarcinomas were analyzed by PCR followed by direct Sanger sequencing.

RESULTS(1) Only 3 cases of hyperplastic polyps lost MLH1 expression, and none of SSAs or traditional adenomas showed loss of MLH1. The negative expression rates of MSH2, MSH6 and MGMT in hyperplastic polyps and SSA were significantly higher than those of traditional adenomas. (2) KRAS mutation was found in 5/10 cases of SSAs, 5/10 traditional adenomas and 1/1 mixed polyps. (3) Colorectal adenocarcinomas harbored the mutations of KRAS (48%, 24/50), BRAF (6%, 3/50) and PIK3CA (4%, 2/50).

CONCLUSIONSImmunophenotypic and gene mutation profiles are different between colorectal serrated lesion and traditional adenoma. Alterations of MMR and MGMT expression play important roles in the pathogenesis of "serrated neoplasm". KRAS mutation is a significant genetic change in the early phase of colorectal carcinogenesis.

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma ; genetics ; metabolism ; Adenoma ; genetics ; metabolism ; Aged ; Class I Phosphatidylinositol 3-Kinases ; Colonic Polyps ; genetics ; metabolism ; Colorectal Neoplasms ; genetics ; metabolism ; DNA Mismatch Repair ; DNA Modification Methylases ; metabolism ; DNA Repair Enzymes ; metabolism ; DNA, Neoplasm ; metabolism ; DNA-Binding Proteins ; metabolism ; Female ; Humans ; Hyperplasia ; Immunophenotyping ; Male ; Middle Aged ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Nuclear Proteins ; metabolism ; Phosphatidylinositol 3-Kinases ; genetics ; Point Mutation ; Precancerous Conditions ; genetics ; metabolism ; Proto-Oncogene Proteins ; genetics ; Proto-Oncogene Proteins B-raf ; genetics ; Proto-Oncogene Proteins p21(ras) ; Sequence Analysis, DNA ; Tumor Suppressor Proteins ; metabolism ; ras Proteins ; genetics

Adaptor Proteins, Signal Transducing ; genetics ; metabolism ; Adenosine Triphosphatases ; genetics ; metabolism ; DNA Mismatch Repair ; DNA Repair Enzymes ; genetics ; metabolism ; DNA-Binding Proteins ; genetics ; metabolism ; Endometrial Neoplasms ; etiology ; genetics ; metabolism ; pathology ; Female ; Genetic Predisposition to Disease ; Humans ; Lynch Syndrome II ; complications ; genetics ; metabolism ; pathology ; Mismatch Repair Endonuclease PMS2 ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; genetics ; metabolism ; Mutation ; Nuclear Proteins ; genetics ; metabolism

Development of controllable hypermutable cells can greatly benefit understanding and harnessing microbial evolution. However, there have not been any similar systems developed for Clostridium, an important bacterial genus. Here we report a novel two-step strategy for developing controllable hypermutable cells of Clostridium acetobutylicum, an important and representative industrial strain. Firstly, the mutS/L operon essential for methyldirected mismatch repair (MMR) activity was inactivated from the genome of C. acetobutylicum to generate hypermutable cells with over 250-fold increased mutation rates. Secondly, a proofreading control system carrying an inducibly expressed mutS/L operon was constructed. The hypermutable cells and the proofreading control system were integrated to form a controllable hypermutable system SMBMutC, of which the mutation rates can be regulated by the concentration of anhydrotetracycline (aTc). Duplication of the miniPthl-tetR module of the proofreading control system further significantly expanded the regulatory space of the mutation rates, demonstrating hypermutable Clostridium cells with controllable mutation rates are generated. The developed C. acetobutylicum strain SMBMutC2 showed higher survival capacities than the control strain facing butanol-stress, indicating greatly increased evolvability and adaptability of the controllable hypermutable cells under environmental challenges.
Butanols ; pharmacology ; Cell Engineering ; methods ; Clostridium acetobutylicum ; cytology ; drug effects ; genetics ; physiology ; DNA Methylation ; genetics ; DNA Mismatch Repair ; genetics ; Evolution, Molecular ; Genome, Bacterial ; genetics ; MutS DNA Mismatch-Binding Protein ; genetics ; Mutation ; Operon ; genetics ; Stress, Physiological ; drug effects ; genetics

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma, Clear Cell ; genetics ; metabolism ; pathology ; surgery ; Adenosine Triphosphatases ; metabolism ; Age Factors ; Carcinoma, Endometrioid ; genetics ; metabolism ; pathology ; surgery ; Colorectal Neoplasms, Hereditary Nonpolyposis ; genetics ; metabolism ; pathology ; surgery ; Cystadenocarcinoma, Serous ; genetics ; metabolism ; pathology ; surgery ; DNA Mismatch Repair ; DNA Repair Enzymes ; metabolism ; DNA-Binding Proteins ; metabolism ; Endometrial Neoplasms ; genetics ; metabolism ; pathology ; surgery ; Female ; Humans ; Mismatch Repair Endonuclease PMS2 ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Neoplasms, Multiple Primary ; genetics ; metabolism ; pathology ; surgery ; Nuclear Proteins ; metabolism

OBJECTIVETo investigate the expression of DNA mismatch repair (MMR) genes (MLH1, MSH2, MSH6 and PMS2) in endometrial adenocarcinoma (EC) of patients under 50 years and to explore the relationship between MMR expression and clinicopathological features including body mass index (BMI), histological grade and pathological stage of EC.

METHODSMMR gene expression was investigated by immunohistochemical S-P method in endometrial adenocarcinomas of patients under age of 50. The control groups included complexity atypical hyperplasia endometrium (CAHE), simple hyperplasia endometrium (SHE), normal endometrium (NE) of patients under age of 50 and EC of patients older than 65 years.

RESULTSTwenty seven of 40 EC (67.5%) lost at least one MMR protein expression. Loss of at least one MMR protein expression was seen in 5/15 cases of CAHE, 1/13 SHE and 1/11 NE, respectively (P < 0.01). The rates of loss of expression of MLH1, MSH2, MSH and PMS2 proteins in EC were 52.5%, 12.5%, 35.0%, and 30.0%, respectively. The difference between MLH1 and MSH6 expression among the four groups were significant (P < 0.05), but the expression of MSH2 showed no significant difference among the groups (P = 0.295). The expression of MMR protein had no relationship with histological grade and pathological stage, although loss of MSH6 was more frequently seen in patients of higher BMI.

CONCLUSIONSAbnormal expression of MMR proteins is correlated with the development of EC from complex atypical hyperplasia. With the exception of the correlation of MSH6 expression with higher BMI, the expression of MMR proteins in EC has no significant relationship with histological grade and pathological stage.

Adaptor Proteins, Signal Transducing ; metabolism ; Adenocarcinoma ; genetics ; metabolism ; pathology ; Adenosine Triphosphatases ; metabolism ; Adult ; Body Mass Index ; DNA Mismatch Repair ; DNA Repair Enzymes ; metabolism ; DNA-Binding Proteins ; metabolism ; Endometrial Neoplasms ; genetics ; metabolism ; pathology ; Female ; Humans ; Immunohistochemistry ; Middle Aged ; Mismatch Repair Endonuclease PMS2 ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; metabolism ; Neoplasm Grading ; Neoplasm Staging ; Nuclear Proteins ; metabolism

OBJECTIVETo study the characteristics of germline mutations of hMLH1, hMSH2 and hMSH6 and promoter methylation status of MLH1 in patients with MSI colorectal cancer.

METHODSSequence analysis of germline mutation and promoter methylation of MLH1 in 34 prospective collected patients with MSI colorectal cancer were performed.

RESULTSNineteen out of 34 patients with MSI colorectal cancer were detected with hypermethylation of MLH1,which accounted for 55.9%. 73.7% MSI-H colorectal cancer cases and 33.3% MSI-L colorectal cancer cases were detected with hypermethylation of MLH1 and the difference was significant. Eight germline mutations were found, including 3 MSH6 mutations and 5 MSH2 mutations.

CONCLUSIONThere are some different characteristics of the germline mutations of hMLH1, hMSH2 and hMSH6 and promoter methylation of MLH1 in Chinese MSI colorectal patients.

Adaptor Proteins, Signal Transducing ; genetics ; Aged ; Base Pair Mismatch ; Colorectal Neoplasms ; genetics ; DNA Methylation ; DNA, Neoplasm ; DNA-Binding Proteins ; genetics ; Female ; Germ-Line Mutation ; Humans ; Male ; Microsatellite Instability ; Middle Aged ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; genetics ; Nuclear Proteins ; genetics ; Sequence Analysis, DNA

OBJECTIVETo detect the germline mutation of mismatch repair gene (MSH6) in hereditary nonpolyposis colorectal cancer (HNPCC) kindreds fulfilling different clinical criteria.

METHODSThe germline mutations of MSH6 gene were detected by PCR based DNA sequencing in 39 unrelated HNPCC probands fulfilling different clinical criteria in which MSH2 and MLH1 mutations were excluded. The exons with missense mutations were analyzed using PCR sequencing in the germline genomic DNA of 137 healthy persons. The expression of MSH6 protein was detected by Envision immunohistochemistry staining in the tumor tissues of the mutational probands.

RESULTSSix germline mutations of MSH6 gene were detected in 39 probands of Chinese HNPCC kindreds, and the mutations distributed in the exon 4, 6, 9 and 10. Four out of six mutations were missense mutation, one was nonsense mutation and the remaining one was insertion mutation in splice site. The results of sequecing for the exons with above four missense mutations in 137 healthy persons' genomic DNA showed that 5 of 137 persons had the missense mutation of c.3488 A to T at codon 1163 of the 6th exon. The mutational rate was approximately 3.65% (5/137), so the mutation could be a single nucleotide polymorphism (SNP). The remaining missense mutations were not found in any germline genomic DNA of 137 healthy persons. Positive expression of MSH6 protein had been identified in the tumor of the SNP proband while the tumors had negative MSH6 protein expression in the rest probands of germline mutation MSH6 gene. The types of mutations and their potential significance were determined by comparing the following databases: http://www.ncbi.nlm.nih.gov/, http://www.ensembl.org/homo-sapies, and http://www.insight-group.org. Five out of the six mutations had not been reported previously and they were new pathological mutations, the rest one was a new SNP.

CONCLUSIONGermline mutations of MSH6 gene may play an important role in Chinese HNPCC kindreds fulfilling different clinical criteria. It is necessary to analyze the germline mutations of MSH6 gene using sequencing to identify HNPCC families in the probands in which MSH2 and MLH1 mutation were excluded.

Adult ; Asian Continental Ancestry Group ; genetics ; Base Pair Mismatch ; genetics ; Colorectal Neoplasms, Hereditary Nonpolyposis ; genetics ; pathology ; DNA Mutational Analysis ; DNA Repair Enzymes ; genetics ; Female ; Germ-Line Mutation ; genetics ; Humans ; Male ; Middle Aged ; MutS DNA Mismatch-Binding Protein ; genetics ; MutS Homolog 2 Protein ; genetics ; Pedigree ; Polymerase Chain Reaction

To determine whether family history of cancer may be a risk factor for the mutator phenotype in colorectal cancer, we recruited 143 consecutive colorectal cancer patients with a family history of accompanying cancers not meeting the Amsterdam criteria. Microsatellite instability (MSI) at 5 markers, hMLH1-promoter methylation, and expression of mismatch repair (MMR) proteins (hMLH1, hMSH2, hMSH6, hMPS1, and hPMS2) were determined. Among the relatives of familial colorectal cancer patients, colorectal cancer was the most common tumor type. Of the proband colorectal cancers, 26 (18.2%) showed high-level MSI (MSI-H); 47 additional tumors with mutator phenotype (32.9%) were identified by hMLH1-promoter methylation and/or loss of MMR protein expression. Mutator phenotype was associated with right-sided colon cancer and the type of accompanying cancer. Family history, which was differentially quantified according to the degree of relatives and the type of accompanying cancers, effectively discriminated MSI-H from microsatellite stable (MSS) and low-level microsatellite instability (MSI-L) and mutator phenotypes. Our findings indicate that familial colorectal cancer may be associated with multiple occurrences of colorectal or accompanying cancers and that family history could be correlated with microsatellite instability.
Adaptor Proteins, Signal Transducing/genetics/metabolism ; Adenosine Triphosphatases/metabolism ; Adult ; Aged ; Aged, 80 and over ; Base Sequence ; Colorectal Neoplasms/*genetics/metabolism/pathology ; DNA Methylation ; DNA Mismatch Repair ; DNA Repair Enzymes/metabolism ; DNA, Neoplasm/genetics ; DNA-Binding Proteins/metabolism ; Female ; Humans ; Male ; *Microsatellite Instability ; Middle Aged ; MutS Homolog 2 Protein/metabolism ; Neoplasm Proteins/metabolism ; Nuclear Proteins/genetics/metabolism ; Phenotype ; Promoter Regions, Genetic ; Risk Factors