OBJECTIVETo investigate cyclooxygenase-2 (COX-2) expression and its relationship with mismatch repair (MMR) protein expression and microsatellite instability (MSI) in hereditary nonpolyposis colorectal cancer (HNPCC).

METHODSA total of 28 cases of colorectal adenoma and 14 cases of colorectal carcinoma were collected between July 2003 and July 2007 from 33 HNPCC families. Sporadic colorectal adenoma (n=32) and carcinoma patients (n=24) served as controls. With samples of tumor tissues and normal colonic mucosa collected from the patients, the protein expressions of COX-2 and MMR (hMLH1, hMSH2, and hMSH6) were examined with immunohistochemical assay. Frequency of MSI in five standard MSI loci BAT25, BAT26, D2S123, D5S346, and D17S250 were analyzed by means of polymerase chain reaction.

RESULTSThe rate of COX-2 high-expression was 53.6% (15/28) and 42.9% (6/14) in HNPCC adenoma and carcinoma; 62.5% (20/32) and 91.7% (22/24) in sporadic adenoma and carcinoma, respectively. That rate was lower in HNPCC carcinoma than in sporadic carcinoma (Pü0.05). MMR-deletion rate and percentage of high-frequency MSI (MSI-H) in HNPCC carcinoma were higher than those in sporadic colorectal carcinoma [both 71.4% (10/14) vs. 12.5% (3/24), both Pü0.01]. Among the 10 MMR-deficient HNPCC carcinoma patients, COX-2 low-expression was observed in 8 cases (80.0%), while COX-2 high-expression was observed in all of the 4 MMR-positive HNPCC carcinoma cases (Pü0.05). In comparison to MMR positive HNPCC carcinoma, HNPCC adenoma, and sporadic carcinoma, COX-2 expression was significantly lower in corresponding MMR-deficient cases (all Pü0.05). The rates of COX-2 low-expression in HNPCC adenoma, HNPCC carcinoma, and sporadic carcinoma with MSI-H were significantly higher than those in the cases with microsatellite stability (all Pü0.05).

CONCLUSIONCOX-2 is expressed at a low level in HNPCC carcinoma, different from the high COX-2 expression in sporadic carcinoma.

Adult ; Aged ; Base Pair Mismatch ; Base Sequence ; Colorectal Neoplasms, Hereditary Nonpolyposis ; genetics ; Cyclooxygenase 2 ; genetics ; DNA Primers ; DNA Repair ; Female ; Humans ; Immunohistochemistry ; Male ; Microsatellite Repeats ; genetics ; Middle Aged

OBJECTIVETo study hMSH2 genetic polymorphism in southern Chinese Han population.

METHODSThe basic materials and blood samples from 163 southern Chinese were collected. The mutations of exon 6 and exon 7 of hMSH2 gene were investigated by PCR-SSCP, followed by DNA sequencing.

RESULTSFragments of 250 bp including exon 6 and fragments of 323 bp including exon 7 of hMSH2 gene were amplified by multiple PCR. The allele frequencies of C18, A82 and B39 type mutations were 0.0184, 0.0031, 0.0031, respectively. The gene frequencies and gene type frequencies of three polymorphism sites in normal population accorded with Hardy-Weinberg equilibrium (P>0.05). The heterozygosity of C18 type mutation (0.0361) was the highest.

CONCLUSIONThere were three polymorphism sites in exon 7 of hMSH2 gene in southern Chinese Han population, among which the genotype frequency of C18 type was the highest, suggesting that C18 type mutation be a useful genetic mark.

Asian Continental Ancestry Group ; genetics ; Base Pair Mismatch ; DNA Ligase ATP ; DNA Ligases ; genetics ; DNA Mismatch Repair ; genetics ; physiology ; DNA Repair Enzymes ; genetics ; Exons ; genetics ; Female ; Humans ; Male ; Microsatellite Repeats ; genetics ; Middle Aged ; Polymorphism, Genetic

DNA mismatch repair gene mutS (2.56 kb) was PCR modified and cloned into a secretive prokaryotic expression vector pET32a (+) which carries a N-terminal His.tag + and thioredoxin sequence. MutS protein was expressed with high level after IPTG induction using the strain E. coli AD494(DE3). SDS-PAGE revealed that the expected protein with a molecular weight of 108 kD which is about 35% of the total bacterial proteins is almost soluble. The expected protein was purified directly by immobilized metal (Ni2+) chelation affinity chromatography and the purity is over 90%. MutS protein activity verified using mismatch DNA showed that the expression product can recognize and bind to base-pair mismatch specifically.
Adenosine Triphosphatases ; biosynthesis ; genetics ; isolation & purification ; Bacterial Proteins ; Base Pair Mismatch ; Chromatography, Affinity ; DNA ; metabolism ; DNA Repair ; DNA-Binding Proteins ; Escherichia coli Proteins ; biosynthesis ; genetics ; isolation & purification ; Magnesium ; pharmacology ; Molecular Weight ; MutS DNA Mismatch-Binding Protein ; Recombinant Proteins ; biosynthesis

PURPOSE: There are numerous prostate cancer-related genes that involve in carcinogenesis and tumor progression. Among the genes, DNA mismatch repair genes recognize and repair misincorporated nucleotides during DNA replication. In this analysis, we evaluated the association of hMSH2 which is one of the mismatch repair genes, with risk of aggressive prostate cancer and prostate cancer recurrence. MATERIALS AND METHODS: Immunohistochemistry was performed in 46 patients who diagnosed prostate cancer and underwent radical prostatectomy between January 2006 and December 2012 at Kyung Hee University Hospital at Gangdong. We evaluated an association between the degree of hMSH2 immunohistochemical staining and various clinical variables including prostate-specific antigen (PSA), Gleason score, pathological stage, and biochemical recurrence. The intensity of immunostaining for hMSH2 was divided into 2 groups: low expression group (immunostaining score < 2) and high expression group (immunostaining score ≥2). RESULTS: Although seminal vesicle invasion was marginally associated with the degree of hMSH2 immunohistochemical staining, PSA, Gleason score, lymph node metastasis, presence of lymphatic, perineural, vascular invasion, and extracapsular extension were not associated with the degree of hMSH2 immunohistochemical staining. Furthermore, the association of biochemical recurrence free survival with hMSH2 expression was not statistically significant. CONCLUSIONS: The hMSH2 expression was marginally associated with risk of aggressive prostate cancer such as seminal vesicle invasion. Further evaluation with a larger number of cases is needed to verify these results.
Base Pair Mismatch ; Carcinogenesis ; DNA Mismatch Repair ; DNA Repair ; DNA Replication ; Gene Expression ; Humans ; Immunohistochemistry ; Lymph Nodes ; Neoplasm Grading ; Neoplasm Metastasis ; Nucleotides ; Prostate ; Prostate-Specific Antigen ; Prostatectomy ; Prostatic Neoplasms ; Recurrence ; Seminal Vesicles

OBJECTIVETo confirm that PCR products with heterozygous mutations contain not only wide-type and mutant homoduplexes, but also two types of heteroduplexes.

METHODSAn insertion-deletion mutation in the exon 1 of KRT9 gene (497delAinsGGCT), which caused Chinese epidermolytic palmoplantar keratoderma (EPPK) was investigated by polymerase chain reaction (PCR), polyacrylamide gel electrophoresis (PAGE) and denaturing high-performance liquid chromatography(DHPLC).

RESULTSTwo heteroduplexes and two homoduplexes in the PCR product from the heterozygous mutation of the exon 1 of KRT9 (497delAinsGGCT) were detected.

CONCLUSIONPCR products from KRT9 gene with heterozygous mutations contain two types of heteroduplexes. It is without the need to perform heating and cooling PCR products obtained from heterozygous mutations in advance before the mutation screening steps such as denaturing gradient gel electrophoresis (DGGE), temperature gradient gel electrophoresis (TGGE), conformation-sensitive gel electrophoresis (CSGE), DHPLC and heteroduplex analysis (HA), etc.

Base Pair Mismatch ; Chromatography, High Pressure Liquid ; DNA Mutational Analysis ; Electrophoresis, Polyacrylamide Gel ; Heteroduplex Analysis ; Heterozygote ; Humans ; Keratin-9 ; Keratins ; genetics ; Mutation ; Nucleic Acid Heteroduplexes ; Polymerase Chain Reaction

Mutagenicity of CORAGRAF (natural coral) and REKAGRAF (hydroxyapatite) was tested in Ames test with and without an external metabolic activation system (S9). The test revealed no mutagenic activity of both locally produced osseous substitutes.
Base Pair Mismatch/drug effects ; Biotransformation/physiology ; Bone Substitutes/*toxicity ; Calcium Carbonate/*toxicity ; Chromosome Aberrations ; Escherichia coli/genetics ; Hydroxyapatites/*toxicity ; *Materials Testing ; *Mutagenicity Tests ; Salmonella typhimurium/genetics

Nowadays, the injury in human mitochondrial DNA (mtDNA) is well known to accumulate in various tissues with age. It's significant to further investigate and then apply it to estimation of the age at parenchymas.
Aging/physiology* ; Base Pair Mismatch/genetics* ; DNA Damage/physiology* ; DNA Fragmentation/genetics* ; DNA, Mitochondrial/physiology* ; Gene Deletion ; Humans ; Polymerase Chain Reaction

OBJECTIVETo study the protein expression pattern of DNA mismatch repair genes hMSH(2), hMLH(1) and the microsatellite instability (MSI) status in the tumor tissue from hereditary nonpolyposis colorectal cancer in the Chinese.

METHODSFifty-eight families fulfilling different clinical criteria including Amsterdam Criteria (AC) (22/24 families, 38 tumors), Japanese Criteria (JC) (12/15 families, 16 tumors) and Bethesda Guidelines (BG) (12/19 patients, 13 tumors) were studied. Monoclonal antibodies against hMSH(2), hMLH(1) proteins and a panel of microsatellite markers (5 loci) including BAT26, BAT25, D2S123, D5S346 and D17S250 were used for study.

RESULTSMSI-H was identified in all 22 (100%) AC tumors, with 81.8% (18/22) showing altered hMSH(2) or hMLH(1) expression; in 14/15 (93.8%) JC cancer, 1/1 (100%) JC adenoma, with 45.5% (5/11) showing altered hMSH(2) or hMLH(1) expression; and in 7/13 (53.8%) BG tumors, with 4/7 showing loss of hMSH(2) or hMLH(1) gene expression.

CONCLUSIONThe frequency of MSI-H and loss of mismatch repair protein are different in the families fulfilling different clinical criteria. Amsterdam Criteria and Japanese Criteria are the two most useful criterion systems for identifying mismatched repair defective tumors. However, Bethesda Guidelines should also be used for detecting more such tumors. The combination of immunohistochemical methods and microsatellite instability analysis is an effective strategy to detect the mismatch repair defective tumors. A close correlation does exist between hMSH(2), hMLH(1) protein expression pattern and MSI status.

Adaptor Proteins, Signal Transducing ; Base Pair Mismatch ; Carrier Proteins ; Colorectal Neoplasms, Hereditary Nonpolyposis ; genetics ; DNA Repair ; DNA-Binding Proteins ; Humans ; Immunohistochemistry ; Microsatellite Repeats ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; Neoplasm Proteins ; genetics ; Nuclear Proteins ; Proto-Oncogene Proteins ; genetics

OBJECTIVETo detect methylation in promoter region of hMSH2 gene in esophageal cancer.

METHODSSpecimens of cancer and normal tissues freshly removed from 32 cases of esophageal cancer patients without previous radiotherapy, chemotherapy or other treatment were preserved at -80 degrees C within 30 min. Methylation specific PCR (MSP) was used to detect methylation of mismatch repair gene (MMR) hMSH2 in promoter region in esophageal cancer and normal esophageal tissues.

RESULTSThe frequencies of methylation of hMSH2 gene in promoter region of cancer and normal esophageal tissues were 32.4% (11/32) and 0/30 (0%), respectively, and significant difference was found between the two groups (P < 0.01). The frequency of methylation in elder patients (> or = 70 years old) was significantly higher than that in younger patients (< 70 years old) (P < 0.05). Methylation was less frequently found in grade I-II (18.2%) than in grade III-IV (70.0%) (P < 0.05).

CONCLUSIONMethylation of hMSH2 gene in promoter region is related to patients' age and histopathological grade of the esophageal cancer.

Aged ; Base Pair Mismatch ; Carcinoma, Squamous Cell ; genetics ; pathology ; DNA Methylation ; Esophageal Neoplasms ; genetics ; pathology ; Female ; Gene Expression Regulation, Neoplastic ; Humans ; Male ; MutS Homolog 2 Protein ; genetics ; Promoter Regions, Genetic ; Transfection

OBJECTIVETo investigate the frequency of large fragment aberrations of MSH2 and MLH1 genes from Chinese colorectal cancer (CRC) patients with family history.

METHODSSixteen exons of MSH2, nineteen exons of MLH1 and seven DNA sequences from the other genes of the samples were screened and checked by multiplex ligation dependent probe amplification (MLPA). First, the methodology was confirmed by testing the positive and negative control samples. Then, 32 CRC or hereditary nonpolyposis colorectal cancer (HNPCC) patients with family history and 20 cases of sporadic CRC were applied to investigate for the large fragment aberrations of MSH2 and MLH1 genes.

RESULTSThe genomic DNA fragment deletions of all positive controls were identified and verified by MLPA. Three cases of 32 familial (hereditary) CRC/HNPCC were detected and identified to be the germline heterozygous deletions of MSH2 gene, of which exons 1-7 were deleted from patient No.3, exon 11 from No.25 and exons 2-6 from No.11. However, no genomic DNA fragment aberration of either MSH2 or MLH1 gene was uncovered from 20 sporadic CRC.

CONCLUSIONLarge DNA fragment aberrations of MSH2 gene was a frequent cause of Chinese HNPCC and CRC patients with family history, and the identification of those aberrations should be included in the regular genetic analysis for CRC/HNPCC patients.

Adaptor Proteins, Signal Transducing ; genetics ; Asian Continental Ancestry Group ; genetics ; Base Pair Mismatch ; China ; Colorectal Neoplasms, Hereditary Nonpolyposis ; ethnology ; genetics ; DNA Mutational Analysis ; Humans ; MutL Protein Homolog 1 ; MutS Homolog 2 Protein ; genetics ; Mutation ; Nuclear Proteins ; genetics