Expressions of genes related to genome stability and DNA repair in nasopharyngeal carcinoma clustering families

Objective： The aim of the study was to observe the expressions of genes related to genome stability and DNA repair in the members of nasopharyngeal carcinoma （NPC） clustedng families. Methods： In the Zhongshan City where there is highly incidence rate of NPC, we chose the members of the NPC clustering families as objects, and the patients of nasopharyngitis and NPC as the control group. We isolated the RNA from the nasopharyngeal tissue, and synthesized its cRNA, the genome stability and DNA repair genes chip technique, chemiluminescent detection and real-time fluorescence quantita- tive technique were used to examine the genome stability and DNA repair genes in the nasopharyngeal tissue. Results： More genome stability and DNA repair genes were up-regulated in the members of the NPC clustering families than the NPC patients, and the range of up-regulated was high, with the over up-regulated 100 times genes including TEP1, MSH4, PMS2LI. Fewer genome stability and DNA repair genes were down-regulated in the members of the NPC clustering families than the NPC patients, the ubiquitin genes almost were down-regulated, the results also could be confirmed by real-time fluorescence quantitative PCR. Conclusion： There are specially expression character of genome stability and DNA repair genes in the members of NPC clustering families.

Microsatellite instability and expression of DNA mismatch repair genes in malignant astrocytic tumors from adult and pediatric patients

Microsatellite instability (MSI) is used as a molecular marker for defective DNA mismatch repair (MMR) genes.We report here alterations of MSI in 15 malignant astrocytomas (WHO grade Ⅲ) and glioblastomas (GBM; WHO grade Ⅳ) of pediatric patients (2-21 years) and 12 GBM from adults (44-68 years) by comparative analysis of BAT25/BAT26 loci and 10 other microsatellite markers. High-level microsatellite instability (MSI-H) occurred in 4 of the 15 pediatric cases (26.7%) and in 1 of the 12 adult GBM cases (8.3%). Low-level mi-

Development of a prognostic signature for esophageal cancer based on a novel 7-DNA damage repair genes signature

Esophageal cancer(EC)was an aggressive malignant neoplasm characterized by high morbidity and poor prognosis.Identifying the changes in DNA damage repair genes helps to better understand the mechanisms of carcinoma progression.In this study,by comparing EC samples and normal samples,we found a total of 132 DDR expression with a significant difference.Moreover,we revealed higher expression of POLN,PALB2,ATM,PER1,TOP3B and lower expression of HMGB1,UBE2B were correlated to longer OS in EC.In addition,a prognostic risk score based on 7 DDR gene expression(POLN,HMGB1,TOP3B,PER1,UBE2B,ATM,PALB2)was constructed for the prognosis of EC.Meanwhile,EC cancer samples were divided into 3 subtypes based on 132 DDR genes expressions.Clinical profile analysis showed cluster C1 and C2 showed a similar frequency of T2,which was remarked higher than that in cluster 3.Moreover,we found the immune cell inflation levels were significantly changed in different subtypes of EC.The infiltration levels of T cell CD8+,B cell and NK cells were greatly higher in cluster 2 than that in cluster 1 and cluster 3.The results showed T cell CD4+infiltration levels were dramatically higher in cluster 1 than that in cluster 2 and cluster 3.Finally,we perform bioinformatics analysis of DEGs among 3 subtypes of EC and found DDR genes may be related to multiple signaling,such as Base excision repair,Cell cycle,Hedgehog signaling pathway,and Glycolysis/Gluconeogenesis.These results showed DDR genes may serve as new target for the prognosis of EC and prediction of the potential response of immune therapy in EC.

Association between the DNA Repair Gene Polymorphisms and Lung Cancer in Turkish Population

Introduction: DNA repair enzymes continuously monitor DNA to correct damaged nucleotide residues generated by exposure to environmental mutagenic and cytotoxic compounds or carcinogens. Our objective was to investigate the association among XRCC1 (Arg399Gln and Arg194Trp), XRCC3 (Thr241Met), XPD-ERCC2 (Lys751Gln), APE1 (Asp241Glu), PARP-ADPRT (Val762Ala) DNA repair gene polymorphisms and lung cancer in Turkish population. Materials and Methods: Our patient group consists of 90 patients with lung cancer and the control group had 100 healthy individuals all of those smoking. DNA was extracted using the whole blood samples. PCR- RFLP technique was used to investigate the polymorphisms on target genes. Results: There was no significant difference in the genotype distributions of XPD Lys751Gln, XRCC1 Arg194Trp, XRCC3 Thr241Met, APE1 Asp241Glu between lung cancer patients and controls for each polymorphism (p > 0.05). However, there was a significant difference between the genotype distributions of XRCC1 Arg399Gln, and PARP Val762Ala in patients and the control group (p > 0.05). Discussion: Only the polymorphisms of XRCC1 codon 399 and PARP Val762Ala alleles are associated with the risk of lung cancer. Other genotypes were not related to lung cancer.

DNA polymorphism and risk of esophageal squamous cell carcinoma in a population of North Xinjiang,China

AIM:To investigate the role of metabolic enzyme and DNA repair genes in susceptibility of esophageal squamous cell carcinoma(ESCC). METHODS:A case-control study was designed with 454 samples from 128 ESCC patients and 326 gender, age and ethnicity-matched control subjects.Genotypes of 69 single nucleotide polymorphisms(SNPs)of metabolic enzyme(aldehyde dehydrogenase-2,ALDH2; alcohol dehydrogenase-1 B,ADHB1;Cytochrome P450 2A6,CYP2A6)and DNA repair capacity genes(excision repair cross complementing group 1,ERCC1; O 6-methylguanine DNA methyltransferase,MGMT; xeroderma pigmentosum group A,XPA;xeroderma pigmentosum group A,XPD)were determined by the Sequenom MassARRAY system,and results were analyzed using unconditional logistic regression adjusted for age,gender. RESULTS:There was no association between the variation in the ERCC1,XPA,ADHB1 genes and ESCC risk.Increased risk of ESCC was suggested in ALDH2 for frequency of presence C allele of SNP [Rs886205:1.626(1.158-2.284)],XPD for C allele [Rs50872:1.482(1.058-2.074)],and MGMT for A allele[Rs11016897:1.666(1.245-2.228)].Five variants of MGMT were associated with a protective effect on ESCC carcinogenesis,including C allele [Rs7069143:0.698(0.518-0.939)],C allele[Rs3793909: 0.6 5 3(0.4 2 9-0.9 9 5)],A a l l e l e[R s 1 2 7 7 1 8 8 2: 0.719(0.524-0.986)],C allele[Rs551491:0.707 (0.529-0.945)],and A allele[Rs7071825:0.618 (0.506-0.910)].At the genotype level,increased risk of ESCC carcinogenesis was found in homozygous carriers of the ALDH2 Rs886205[CC vs TT,odds ratios(OR): 3.116,95%CI:1.179-8.234],MGMT Rs11016879(AA vs GG,OR:3.112,95%CI:1.565-6.181),Rs12771882 (AA vs GG,OR:2.442,95%CI:1.204-4.595),and heterozygotes carriers of the ALDH2 Rs886205 (CT vs TT,OR:3.930,95%CI:1.470-10.504), MGMT Rs11016879(AG vs GG,OR:3.933,95%CI: 2.216-6.982)and Rs7075748(CT vs CC,OR:1.949, 95%CI:1.134-3.350),respectively.Three variants were associated with a protective effect on ESCC carcinogenesis,carriers of the MGMT Rs11016878(AG vs AA,OR:0.388,95%CI:0.180-0.836),Rs7069143(CT vs CC,OR:0.478,95%CI:0.303-0.754)and Rs7071825(GG vs AA,OR:0.493,95%CI:0.266-0.915). Increased risk of ESCC metastasis was indicated in MGMT for frequency of presence C allele[Rs7068306: 2.204(1.244-3.906)],A allele[Rs10734088:1.968 (1.111-3.484)]and C allele[Rs4751115:2.178(1.251-3.791)].Two variants in frequency of presence C allele of CYP2A6[Rs8192720:0.290(0.099-0.855)] and A allele of MGMT[Rs2053139:0.511(0.289-0.903)] were associated with a protective effect on ESCC progression.Increased risk of ESCC metastasis was found in heterozygote carriers of the MGMT Rs7068306 (CG vs CC,OR:4.706,95%CI:1.872-11.833).CONCLUSION:Polymorphic variation in ALDH2,XPD and MGMT genes may be of importance for ESCC susceptibility.Polymorphic variation in CYP2A6 and MGMT are associated with ESCC metastasis.

The mutation landscape of multiple cancer predisposition genes in Chinese familial/hereditary breast cancer families

Objective:Approximately 5%–10%of breast cancer(BC)patients display familial traits that are genetically inherited among the members of a family.The purpose of this study was to profile the germline mutations in 43 genes with different penetration rates and their correlations with phenotypic traits in Chinese familial BC families.Methods:Ion Torrent S5™-based next generation sequencing was conducted on 116 subjects from 27 Chinese familial BC families.Results:Eighty-one germline mutations in 27 BC predisposition genes were identified in 82.8%(96/116)of the cases.Among these,80.8%of the mutated genes were related to DNA damage repair.Fourteen possible disease-causing variants were identified in 13 of 27 BC families.Only 25.9%(7/27)of the BC families exhibited hereditary deficiency in BRCA1/2 genes,while 22.2%of the BC families exhibited defects in non-BRCA genes.In all,41.7%(40/96)of the mutation carriers had BRCA mutations,88.5%(85/96)had non-BRCA mutations,and 30.2%(29/96)had both BRCA and non-BRCA mutations.The BC patients with BRCA mutations had a higher risk of axillary lymph node metastases than those without mutations(P<0.05).However,the BC patients with non-BRCA mutations frequently had a higher occurrence of benign breast diseases than those without mutations(P<0.05).Conclusions:In addition to BRCA1/2,genetic variants in non-BRCA DNA repair genes might play significant roles in the development of familial/hereditary BC.Therefore,profiling of multiple BC predisposition genes should be more valuable for screening potential pathogenic germline mutations in Chinese familial/hereditary BC.

Molecular evolutionary analysis of gene families encoding DNA recombination and repair proteins and histone demethylases,and their functional implications

Many eukaryotic genes are members of multi-gene families due to gene duplications, which generate new copies that allow functional divergence. However, the relationship between

Promoter methylation status of hMLH1,MGMT,and CDKN2A/p16 in colorectal adenomas

AIM:To investigate aberrant DNA methylation of CpG islands and subsequent low-or high-level DNA microsatellite instability(MSI)which is assumed to drive colon carcinogenesis. METHODS:DNA of healthy individuals,adenoma(tu-bular or villous/tubulovillous)patients,and colorectal carcinoma patients who underwent colonoscopy was used for assessing the prevalence of aberrant DNA methylation of human DNA mismatch repair gene mutator L homologue 1(hMLH1),Cyclin-dependent kinase inhibitor 2A(CDKN2A/p16),and O-6-methylguanine DNA methyltransferase(MGMT),as well as their rela- tion to MSI. RESULTS:The frequency of promoter methylation for each locus increased in the sequence healthy tissue/adenoma/carcinoma.MGMT showed the highest frequency in each group.MGMT and CDKN2A/p16 presented a statistically significant increase in promoter methylation between the less and more tumorigenic forms of colorectal adenomas(tubular vs tubullovillous and villous adenomas).All patients with tubulovillous/villous adenomas,as well as all colorectal cancer patients,showed promoter methylation in at least one of the examined loci.These findings suggest a potentially crucial role for methylation in the polyp/adenoma to cancer progres- sion in colorectal carcinogenesis.MSI and methylation seem to be interdependent,as simultaneous hMLH1, CDKN2A/p16,and MGMT promoter methylation was present in 8/9 colorectal cancer patients showing the MSI phenotype. CONCLUSION:Methylation analysis of hMLH1,CD- KN2A/p16,and MGMT revealed specific methylation profiles for tubular adenomas,tubulovillous/villous adenomas,and colorectal cancers,supporting the use of these alterations in assessment of colorectal tumorigenesis.

Comparison of screening strategies for Lynch syndrome in patients with newly diagnosed endometrial cancer:a prospective cohort study in China

Background: The prevalence of Lynch syndrome and screening strategies for this disorder in Chinese patients with endometrial cancer have seldom been investigated. Such data would be essential for the screening, prevention, genetic counseling, and treatment of Lynch syndrome. The purpose of this prospective study was to determine the accuracy of the mismatch repair (MMR) protein immunohistochemistry (IHC), microsatellite instability (MSI) test, and clinical diagnostic criteria in screening for Lynch syndrome-associated endometrial cancer (LS-EC) in a prospective Chinese cohort. Methods: All patients with newly diagnosed endometrial cancer (EC) were evaluated using clinical diagnostic criteria (Amsterdam II criteria and the revised Bethesda guidelines), MSI test, and IHC of MMR proteins in tumor tissues. For all patients, the screening results were compared with results of germline sequencing for pathogenic variants of MMR genes. Results: Between December 2017 and August 2018, a total of 111 unselected patients with newly diagnosed EC were enrolled. Six patients (5.4%) harbored a pathogenic germline mutation of MMR genes: 1 had a mutation in MutL homolog 1 (MLH1), 2 in MutS homolog 2 (MSH2), and 3 in MutS homolog 6 (MSH6). The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) for identifying LS-EC were 33.3%, 88.6%, 14.3%, and 95.9%, for the clinical criteria, 66.7%, 75.0%, 14.3%, and 97.3% for IHC of MMR proteins, 100%, 89.9%, 33.3%, and 100% for MSI test, and 100%, 72.4%, 20.0% and 100% for combined IHC and MSI test, respectively. The combination of IHC and MSI test had higher sensitivity and PPV than the clinical criteria (p = 0.030). MSI test and IHC were highly concordant for LS-EC screening (73/77, 94.8%). Conclusion: The accuracy of the combination of IHC of MMR proteins and MSI test for screening LS among Chinese patients with EC was superior to that of the clinical criteria.