hMSH2 Gene Research Articles

Polymorphisms of mismatch repair gene hMLH1 and hMSH2 and risk of gastric cancer in a Chinese population

The purpose of this study was to determine the genotype and allele frequencies of hMLH1 (-93G>A and I219V) and hMSH2 (-118T>C and IVS12-6T>C) polymorphisms in patients with gastric carcinoma and normal controls, and to evaluate the association between these polymorphisms and the risk of gastric cancer in a hospital-based Chinese population. Genomic DNA was extracted from peripheral blood lymphocytes. A TaqMan assay was used to determine the genotype and allele frequencies of hMLH1 and hMSH2 polymorphisms in data obtained from 554 gastric cancer cases and 592 controls. Unconditional logistic regression was used to assess the association between the four single nucleotide polymorphisms (SNPs) and gastric carcinoma risk. No evidence of an association among any of the four polymorphisms and the risk of gastric cancer was observed. However, when gastric cancer patients were further stratified by age, gender, smoking status, alcohol use and clinicopathological characteristics, and compared with the control populations, the combined variant genotype hMSH2 -118T>C (TC+CC) was not only associated with an increased risk of gastric cancer in subgroups of younger subjects [ages ≤63years; adjusted odds ratio (OR)=1.51, 95% confidence interval (CI), 1.05-2.16], but also with diffuse tumors (adjusted OR=1.41, 95% CI, 1.01-1.96). These data indicate that the polymorphisms of -93G>A, I219V and IVS12-6T>C are not associated with the risk of gastric cancer. However, hMSH2-118T>C combined with variant genotypes (TC+CC) may confer a potential risk of gastric cancer in the Chinese population.

Analysis of Aberrant Methylation in DNA Repair Genes During Malignant Transformation of Human Bronchial Epithelial Cells Induced by Cadmium

Cadmium (Cd) and its compounds are well-known human carcinogens, but the mechanisms underlying the carcinogenesis are not entirely understood yet. Aberrant methylation was investigated in order to obtain insight into the DNA repair-related epigenetic mechanisms underlying CdCl(2)-induced malignant transformation of human bronchial epithelial cells (16HBE). Gene expression and DNA methylation were assessed in untreated control cells; 5th, 15th, and 35th passage of CdCl2-treated cells and tumorigenic cells (TCs) from nude mice by using high-performance liquid chromatography, real-time PCR, Western blot analysis, and methylation-specific PCR assay. During Cd-induced malignant transformation, global DNA methylation progressively increased and was associated with the overexpression of the DNA methyltransferase genes DNMT1 and DNMT3a but not DNMT3b. Expression of both the messenger RNA and proteins of the DNA repair genes (hMSH2, ERCC1, XRCC1, and hOGG1) progressively reduced and DNA damage increased with Cd-induced transformation. The promoter regions of hMSH2, ERCC1, XRCC1, and hOGG1 were heavily methylated in the 35th passage transformed cells and the TCs. The DNA demethylating agent 5-aza-2'-deoxycytidine could reverse the Cd-induced global DNA hypermethylation, DNMT hyperactivity, and the silencing of hMSH2, ERCC1, XRCC1, and hOGG1 in a time-dependent manner. The results indicate that DNMT1 and DNMT3a overexpression can result in global DNA hypermethylation and silencing of the hMSH2, ERCC1, XRCC1, and hOGG1 genes. They may partly explain the epigenetic mechanisms underlying the carcinogenesis due to Cd.

Aberrant methylation in promoter-associated CpG islands of multiple genes in chronic myelogenous leukemia blast crisis

Chronic myelogenous leukemia (CML) has a typical progressive course with transition from a chronic phase to a terminal blast crisis phase. The mechanisms that lead to disease progression remain to be elucidated. To understand the role of aberrant methylation in the progression of CML, DNA methylation patterns in 16 patients with CML blast crisis were analyzed. Methylation status was analyzed by methylation-specific PCR (MSP) for 13 genes, including cell cycle regulating genes, DNA repair genes, apoptosis-related genes, a differentiation-associated gene and a cytokine signaling gene. The frequency of samples with methylation in each of the following genes were: p15, 18%; MGMT, 12%; RARβ, 12%; p16, 6%; DAPK, 6% and FHIT, 6%. In total, four (25%) cases showed methylation of at least one gene. None of the 16 cases showed hypermethylation of the hMLH1 or hMSH2 genes. These results suggest that hypermethylation of cell cycle control genes, but not DNA mismatch repair genes, play a significant role in the progression of CML.

Promoter methylation status of hMLH1, hMSH2, and MGMT genes in colorectal cancer associated with adenoma–carcinoma sequence

Epigenetic silencing of the DNA mismatch repair genes has been poorly described in colorectal carcinomas showing the classic adenoma-carcinoma pathway of carcinogenesis. The aim of this study was to investigate the methylation status of MutL homolog 1 (hMLH1), MutS homolog 2 (hMSH2), and O-6-methylguanine-DNA methyltransferase (MGMT) in a series of colorectal carcinomas that contain both adenomas and carcinomas. Promoter methylation of hMLH1, hMSH2, and MGMT was evaluated in normal mucosa, adenoma, and carcinoma samples from 112 colorectal cancer patients. Methylation was assessed by bisulfite modification and methylation-specific PCR. Expression of the gene products was also examined by immunohistochemistry. Of the 112 adenomas, methylation was detected for hMLH1 (2, 1.8%), hMSH2 (9, 8.0%), and MGMT (38, 33.9%). In the carcinoma samples, methylation was seen in hMLH1 (2, 1.8%), hMSH2 (15, 13.4%), and MGMT (53, 47.3%). In normal mucosa, hMSH2 (6, 5.4%) and MGMT (12, 10.7%) were methylated, whereas hMLH1 was not. Immunohistochemical analysis revealed abnormal hMLH1 (14, 12.5%), hMSH2 (11, 9.8%), and MGMT (53, 47.3%) expression with a significant correlation between aberrant MGMT methylation and a loss of MGMT expression. These data suggest that CpG island methylation in hMSH2 and MGMT, but not hMLH1, is closely related to carcinogenesis in colorectal carcinomas presenting with a conventional adenoma-carcinoma sequence. Therefore, the detection of hMSH2 and MGMT methylation may have clinical significance in the evaluation of colon cancer patients and in tumor-specific management of the disease.

Clinical implications of mismatched repair gene promoter methylation in pancreatic cancer

To investigate the relationship between the hypermethylation statuses of the mismatch repair genes (hMLH1 and hMSH2) promoters and explore the correlation between it and the development of pancreatic cancer and the biological behavior of pancreatic cancer. We selected 90 patients who were diagnosed with pancreatic cancer and underwent radical operations in the First Affiliated Hospital of the Dalian Medical University between January 2002 and June 2008. The methylation status of the hMLH1 and hMSH2 promoters was detected by methylation-specific polymerase chain reaction (MSP). Meanwhile, the expression of hMLH1 and hMSH2 protein was detected by Western blot and immunohistochemistry, and its correlation with biological behavior of pancreatic cancer was explored. Of the 90 cases, hMLH1 promoter methylation was detected in 54 (60.0%) patients, while none of the paracancerous tissues indicated methylation. In the study, the hMLH1-methylated tumors lost hMLH1 protein expression, but the non-hMLH1-methylated tumors were not seen to have a loss of hMLH1 protein expression (P < 0.001). On the other hand, there were four cases of hMSH2 promoter methylation. However, no significant difference was found between hMSH2 promoter methylation and non-hMSH2 promoter methylation cases (P > 0.05). After universal analysis, hMLH1 expression was significantly related to tumor differentiation, lymph node metastasis, and tumor location (P < 0.05) while not related to the age, sex, and tumor size (P > 0.05). Our study suggests that the mismatch repair genes play an important role in pancreatic cancer carcinogenesis and progression through epigenetic modification, and it may be regarded as a potential target for the management of pancreatic cancer.

Single Nucleotide Polymorphism (SNPs) of DNA repair genes (hMLH1 and hMSH2) in Rheumatoid arthritis Patients and its association with rheumatoid arthritis by Smoking status

The purpose of this study is to examine the risk factors and the single nucleotide polymorphisms(SNPs) of DNA repair gene (hMLH1 and hMSH2) associated with rheumatoid arthritis by smoking status and environmental tobacco smoke(ETS). This study was planned to detect the susceptibility of the patients diagnosed by rheumatoid arthritis to the single nucleotide polymorphisms (SNPs) of DNA repair gene(hMLH1 and hMSH2) by smoking status and environmental tobacco smoke(ETS). The single nucleotide polymorphisms(SNPs) of DNA repair gene(hMLH1 and hMSH2) were analyzed by Dynamic allele specific hybridization(DASH) technique in rheumatoid arthritis patients and controls. The single nucleotide polymorphisms(SNPs) of DNA repair gene(hMLH1 and hMSH2) of patients were compared to those of age and sex-matched controls, which are statistically analyzed and adjusted by age, sex, smoking status, and ETS. This study showed that; The SNP of DNA repair gene hMLH1 was significantly associated with the susceptibility of rheumatoid arthritis, but that of hMSH2 was not. Differential effect of passive smoking on the association between the SNP of DNA repair gene hMSH2(CC type or CT type) and rheumatoid arthritis risk was found. It is suggested that the SNPs of DNA repair gene correlated with susceptibility to rheumatoid arthritis by smoking status was able to be used as its susceptibility marker and further as basic data to prevent the risk factors or rheumatoid arthritis. But the larger sample studies, including a variety of SNPs of DNA repair gene will be needed.

Clinicopathologic and genetic features of Chinese hereditary nonpolyposis colorectal cancer (HNPCC).

382 Background: Hereditary non-polyposis colorectal cancer (HNPCC) is the most common hereditary colorectal cancer (CRC). At least five mismatch repair genes, majorly hMLH1and hMSH2 gene mutations, are associated with this syndrome. Given the geographical and racial differences, Chinese HNPCC patients have some special characteristics compared with patients in West countries. Based on our former studies, we developed a criteria, the Fudan Criteria, for clinical diagnosis of Chinese HNPCC. The aim of this study is (1) to understand the relationship between genotype and phenotype in Chinese HNPCC; and (2) to investigate the clinical value of Fudan Criteria. Methods: 116 unrelated probands of HNPCC or suspected HNPCC families from the Fudan Colorectal Registry were studied. 32 families fulfilled the Amsterdam criteria (AC group), 28 families fulfilled the Fudan Criteria (FD group). 56 families met the revised Bethesda guideline (BG Group). Direct DNA sequencing of all exons of hMSH2 and hMLH1 genes were performed. Mutation and clinicalpathological features were compared between the groups. Results: 32 pathological germline mutations were identified. 16/32 mutations were located at hMLH1 and 16/32 located at hMSH2. The sensitivity of Amsterdam Criteria was 50%, specificity was 81% and Youden's index was 31%. The sensitivity of Fudan Criteria was 75%, specificity was 58% and Youden's index was 33%. In AC group, there were no significant clinicopathological differences in patients with or without mutation. However, families with hMSH2 mutation had a higher ratio of synchronous and metachronous CRC than families with hMLH1 mutation (33% vs. 6%; P=0.04). Families in AC group share the same clinicopathological features with families in FD group, except multiple relative tumors (21.6% vs.6%; P=0.001). Conclusions: There seems no close relation between genotype and phenotype, except patients with hMSH2 mutation more frequently harbor synchronous and metachronous CRC. Fudan Criteria had a little higher sensitivity and accuracy than Amsterdam Criteria for identification of Chinese HNPCC. No significant financial relationships to disclose.

Association between the hMSH2 IVS12-6 T&gt;C polymorphism and cancer risk: A meta-analysis

The hMSH2 gene, a member of the mismatch repair (MMR) pathway, plays a key role in the maintenance of genomic integrity. The common sequence variation in hMSH2, IVS12-6 T>C, has been implicated in cancer risk. However, the results of published studies on this polymorphism remain conflicting. Hence, we conducted a meta-analysis to clarify the role of the hMSH2 IVS12-6 T>C polymorphism in cancer. We performed a comprehensive literature search updated to March 2011 of studies on the associations between the hMSH2 IVS12-6 T>C polymorphism and cancer risk. Odds ratios (ORs) and 95% confidence intervals (CIs) were used to assess the strength of the associations. Thirteen studies involving 7,527 patients and 8,762 control subjects were included in this meta-analysis. The overall results indicated no major influence of the polymorphism on cancer risk. However, stratified analysis by cancer types showed that the hMSH2 IVS12-6 polymorphism increased the risk for non-Hodgkin's lymphomas (heterozygote comparison: OR=1.62; 95% CI 1.06-2.47). When stratified by the source of controls, significant associations were observed in hospital-based populations (heterozygote comparison: OR=1.28; 95% CI 1.02-1.61). These results indicate that the polymorphism of hMSH2, IVS12-6, may cause a different effect in different types of cancers. To draw more comprehensive conclusions, further prospective studies with larger numbers of participants worldwide are required to examine the associations between this polymorphism and cancer risk.

A new mutation in the hMSH2 gene in a Spanish Lynch syndrome family

We report a new germline mutation in exon 13 of the hMSH2 gene (c.2081T>C; F694S) in a patient diagnosed with colorectal carcinoma. The patient's family fulfilled the clinical criteria of the Bethesda guidelines for Lynch syndrome. The segregation analysis determined the presence of the mutation in the proband's mother (breast cancer younger than 40 years old) and in two healthy daughters. The mutation was not present in 116 normal controls screened. The medical implications for the carrier relatives are discussed.

The correlation between serum estrogen level and the expression of mismatch repair genes in colonic mucosa

Objective To investigate the effects of estrogen on mismatch repiar gene expression in colonic mucosa in vivo. Methods A total of 42 healthy individuals underwent colonoscopy were enrolled in the study. Half an hour before colonoscopy examination, blood sample was taken for determining the serum estradiol (E2) level. N ormal colonic mucosal tissues determined by naked eye under colonoscopy examination were taken in the right hemi colon to detect HMLH1 and hMSH2 gene expression by semi-quantitative RT-PCR and immunohistochemistry staining. Then the correlation of serum E2 levels with hMLH1 and hMSH2 expression in colonic mucosa was analyzed. Results A bimodal curve was presented for the correlation between serum E2 level in healthy individuals and hMLH1 expression in colonic mucosa. A strong positive correlation of E2 level with hMLH1 expression in normal colonic mucosa was observed when serum E2 level was more than 45 pg/ml (For mRNA, P=0. 003, r=0. 701; for immunohistochemistry positivity index, P=0. 000, r=0. 874).However there was no correlation between E2 level and hMSH2 expression. Conclusion High serum E2 level might increase the hMLH1 gene expression in colonic mucosa in vivo. Key words: Estrogen; Mismatch repair; Colorectal cancer

Expression and significance of mismatch repair genes hMLH1 and hMSH2 in sporadic colorectal carcinoma

To investigate the expression and clinical significance of mismatch repair genes hMLH1 and hMSH2 in sporadic colorectal carcinoma tissues. The expression of hMLH1 and hMSH2 proteins was detected in the 63 sporadic colorectal carcinoma samples by immunohistochemical staining, including tumor tissue, adjacent tissue at 3 cm from the carcinoma, and normal tissue at 10 cm away from the tumor. The positive rate of hMLH1 protein expression in the 63 normal colorectal tissues, adjacent tissues and sporadic colorectal carcinoma tissues was 95.2%, 85.7% and 81.0%, respectively. The positive rate of hMLH1 protein expression was significantly lower in the tumor than in normal colorectal tissues (P < 0.05). The positive rate of hMSH2 protein in the 63 normal colorectal tissues, adjacent tissues and sporadic colorectal carcinoma tissues were 76.2%, 66.7% and 52.4%, respectively. The positive rate of hMSH2 protein expression was significantly lower in the tumor than in normal colorectal tissues (P < 0.01). The positive rate of hMLH1 protein expression was significantly higher in the tumor tissue of patients aged younger than 60 years (100%) than that in patients ≥ 60 years (75.0%, P < 0.05). The positive rate of hMLH1 protein expression in the tumor tissue accompanied by lymphatic metastasis was 50.0%, significantly lower than that (93.3%) in tumors without lymphatic metastasis (P < 0.05). The positive rate of hMSH2 protein expression in the tumor tissue of patients aged younger than 60 years was 80.0%, significantly higher than that (43.8%) in the cases ≥ 60 years (P < 0.05). The positive rate of hMSH2 protein expression in the tumor tissues with invasion reaching to the intestinal serosa (61.5%) was significantly higher than that (37.5%) in the tumors invading to submucosa or muscular layer (P < 0.05). There was a positive correlation between the expressions of hMLH1 and hMSH2 proteins in the sporadic colorectal carcinomas. There is a certain loss of expression of hMLH1 and hMSH2 proteins in sporadic colorectal carcinoma, and is correlated with the age of patients, lymphatic metastasis and different depth of cancer invasion. HMLH1 and hMSH2 may be used as a useful laboratory marker in clinical judgement of occurrence and development of sporadic colorectal carcinoma.

Analysis of the hMSH2 Gene Variants in Head and Neck Cancer

The hMSH2 (human MutS homolog 2) gene plays a central role in DNA mismatch repair. Structural variations in the gene may lead to protein instability and deficient mismatch repair. However, the role of polymorphic variants of the hMSH2 gene have not been defined in head and neck cancer. In this study, the roles of three polymorphic variants in the functional domains of the gene were investigated in 166 patients with head and neck cancer by allele-specific PCR, electronical array addressing, and PCR/RFLP (restriction fragment length polymorphism). This is the first study to investigate the gIVS12-6T --> C polymorphism in head and neck cancer. A significant association between the CC genotype and reduced risk of disease suggests that the gIVS12-6T --> C substitution at the splice-acceptor site may affect the risk of head and neck cancer. We did not observe an association between the Asn127Ser and Gly322Asp polymorphisms and cancer risk. A possible role of the gIVS12-6T --> C substitution warrants further validation in larger cohorts because of low allele frequency.

Systemic chemotherapy-induced microsatellite instability in the mononuclear cell fraction of women with breast cancer can be reproduced in vitro and abrogated by amifostine

Microsatellite instability (MSI) induction by alkylating agent-based chemotherapy (ACHT) may underlie both tumor resistance to chemotherapy and secondary leukaemias in cancer patients. We investigated if ACHT could induce MSI in tumor-derived plasma-circulating DNA (pfDNA) and in normal peripheral blood mononuclear (PBMN) cells. We also evaluated if amifostine could interfere with this process in an in-vitro model. MSI was determined in pfDNA, PBMN cells and urine cell-free DNA (ufDNA) of 33 breast cancer patients before and after ACHT. MCF-7 cells and PBMN from normal donors were exposed in vitro to melphalan, with or without amifostine. We observed at least one MSI event in PBMN cells, pfDNA or ufDNA of 87, 80 and 80% of patients, respectively. In vitro, melphalan induced MSI in both MCF-7 and normal PBMN cells. In PBMN cells, ACHT-induced MSI occurred together with a significant decrease in the expression of the DNA mismatch repair gene hMSH2. Amifostine decreased hMSH2 expression and also prevented MSI induction only in normal PBMN cells. ACHT induced MSI in PBMN cells and in tumour-derived pfDNA. Because of its protective effect against ACHT induction of MSI in normal PBMN cells in vitro, amifostine may be a potential agent for preventing secondary leukaemias in patients exposed to ACHT.

Methylation status of promoter of mismatch repair gene hMLH1 and hMSH2 in glioma

Objective To explore the methylation status of hMLH1 and hMSH2 promoter region in glioma and its role in the oncogenesis. Methods Methylation status of the hMLH1 and hMSH2 promoter region was assayed in 51 giioma tissues and giioma cell line U251 by methylation-specific polymerase chain reactio (MSP). Results The promoter methylations of hMLH1 and hMSH2 were not found in all of 7 nor-real cerebral tissues. The incidence of methylation in hMLH1 and hMSH2 promoter was 13.7% (7/51), and 35.3% (18/51 ) , respectively in 51 glioma tissues accompanied by unmethytation of hMLH1 and hM-SH2. Methylation frequency of the two genes was not correlated with sex, age and pathological classifica-tion. The incidence of hMLH1 promoter methylations in grade Ⅰ -Ⅱ was 0.0% (0/25), and that was 26. 9% (7/26) in grade Ⅲ-Ⅳ (χ~2 = 5.69,P < 0.05 ). Promoter methylation of the hMSH2 gene was present in cell line U251, but that was not observed for the hMLH1 gene. Conclusion The promoter methylations of hMLH1 and hMSH2 in glioma are not correlated with sex, age and pathological classification. Methyla-tion of hMSH2 promoter exists in glioma with median frequency, which may be an early event and correla-ted with the occurrence of glioma. Methylation of hMLH1 promoter exists in glioma with relatively low fre-quency, and the promoter methylation of hMLH1 in giioma is correlated with pathological grade, hMSH2 promoter (C_PG island) hypermethylation exists in glioma cell line U251. Key words: Glioma; Base pair mismatch; DNA methylation

Loss of hMSH2 gene expression correlates with improved survival in patients with sporadic colorectal cancer

gene expression hadthe tendency to longer survival in all Dukes’ stages.Loss of mismatch repair (MMR) function is implicatedin the phenomena of microsatellite instability (MSI), whichis characterized by the accumulation of somatic alterationin the length of simple, repeated sequences; microsatellites(Ahmed 2003). MSI has been identified in tumours of hered-itary non-polyposis colorectal cancer (HNPCC) colorectalcancer and sporadic colorectal cancer, where it occurs in 10–15% of the cases (Gryfe

IVS10+12A>G polymorphism in hMSH2 gene associated with prognosis for patients with colorectal cancer

BackgroundThe polymorphisms in DNA repair genes may contribute to a variation in the DNA repair capacity, thereby affecting the risk of carcinogenesis and prognosis of colorectal cancer. Accordingly, the present study analyzed 14 polymorphisms in DNA repair genes and their impact on the prognosis for patients with colorectal cancer. Materials and methodsThree hundred and ninety-seven consecutive patients with curatively resected colorectal adenocarcinoma were enrolled in the present study. The genomic DNA was extracted from fresh colorectal tissue and 14 polymorphisms of DNA repair genes determined using a real-time PCR genotyping assay. ResultsThe median age of the patients was 63 years, and 218 (54.9%) patients had colon cancer, while 179 (45.1%) patients had rectal cancer. A multivariate survival analysis, including age, differentiation, carcinoembryonic antigen level, and stage, revealed a better survival for the patients with the combined IVS10+12AG and GG genotype than for the patients with the IVS10+12AA genotype [disease-free survival: hazard ratio (HR) 0.47, 95% confidence interval (CI) 0.30–0.75, P = 0.002; overall survival: HR 0.50, 95% CI 0.26–0.98, P = 0.042]. None of the other polymorphisms was associated with survival. ConclusionThe IVS10+12A>G polymorphism in the hMSH2 gene was found to be an independent prognostic marker for patients with colorectal cancer.

HMLH1 and hMSH2 gene mutations in a population susceptible to gastric cancer

hMLH1 and hMSH2 gene mutations in a population susceptible to gastric cancer

Relationship between mismatch repair gene hMSH2 promoter methylation and gastric carcinoma

Relationship between mismatch repair gene hMSH2 promoter methylation and gastric carcinoma

Age Related Expression of hMLH1 but Not hMSH2 in Human Hematopoietic Stem Cells Predicts Genomic Instability.

Abstract 3235Poster Board III-172DNA damage repair pathways have been shown to be important for hematopoietic function and longevity. A number of studies focusing on the loss of DNA damage repair genes have reported age related loss of hematopoietic stem cells, reduced hematopoietic function, and increased rates of hematologic cancer. A poorly studied pathway with respect to its effect on hematopoietic function is the mismatch repair (MMR) pathway. Microsatellite instability (MSI), one marker of MMR failure, has been observed in acute lymphoblastic leukemia, myelodysplastic syndrome, and lymphocytes obtained from the peripheral blood of the elderly. Further, studies investigating MMR pathway disruption in mice show an increased incidence of age related hematologic disorders and failure to repopulate in competitive transplant experiments. These reports led to the formation of the hypothesis that age related loss of MMR in a subset hematopoietic stem/progenitor cells (HSC) leads to a progenitor population with a mutator phenotype potentially leading to cell death or leukemogenesis.To test this hypothesis we clonally expanded HSC from cord blood, bone marrow, and bone core samples from various aged individuals most of whom had normal CBCs. These colony forming units (CFU) were then tested for MSI at five microsatellite loci previously used in the diagnosis of the MMR defective disease HNPCC (BAT 25, BAT 26, D2S123, D5S346, and D17S250). These results showed a statistically significant increase in high grade instability (measured as MSI observed at >20% of loci tested) in CFU obtained from individuals over the age of 50 compared to those in the age range between 0 and 50 years (p=0.0034). Next we sought to determine if loss of gene expression in MMR genes could account for the observed MSI. Gene expression of two genes known to be transcriptionally downregulated in MMR failure, hMLH1 and hMSH2, were assessed by qRT-PCR in CFU obtained from pure CD34+ immunomagnetic separations of HSC from various aged donors. Further, individual CD34+ cells from these same donors were fixed to slides and immunostained for hMLH1 and hMSH2. We observed a significant loss of hMLH1 gene expression in a subset of HSC obtained from older donors above age 42, but no pattern of loss of hMSH2 gene expression. The age related loss of MMR in HSC suggests that MMR pathway proficiency is important for hematopoiesis. These results suggest that loss of MMR might precede myelodysplastic syndromes and leukemia in older individuals. DisclosuresNo relevant conflicts of interest to declare.

6099 IVS10+12A>G polymorphism in hMSH2 gene associated with prognosis for patients with colorectal cancer

The adipocytokines eNampt and resistin are involved in the regulation of inflammation exerting pro-inflammatory actions. Our aim was to jointly investigate whether circulating eNampt and resistin, and their kinetics predict 28-day mortality of sepsis.In a prospective study, serum eNampt and resistin were determined in 102 critically ill patients fulfilling the diagnostic criteria of SEPSIS-3, at enrollment and one week after, and in 102 healthy controls matched on age, gender and month of diagnosis.Serum eNampt and resistin were significantly higher in septic patients than controls (p < 0.001), and higher in septic shock compared to sepsis (p < 0.001). Both eNampt and resistin decreased significantly during the first week of sepsis (p < 0.001). However, patients with septic shock presented a sustained elevation of eNampt and resistin compared to patients with sepsis. Both adipocytokines were positively correlated with sepsis severity scores and lactate. Baseline eNampt was a better discriminator of sepsis and septic shock compared to C-reactive protein and procalcitonin. Serum eNampt and resistin were higher in nonsurvivors than in survivors during the first week of sepsis. Prolonged and sustained elevation of both eNampt and resistin, as reflected by a lower percentage change from their baseline values, was independently associated with 28-day mortality (HR: 0.05, 95% C.I. 0.01–0.28, p = 0.001; HR: 0.19, 95% C.I. 0.07–0.50, p = 0.001, respectively), after adjustment for significant clinical and laboratory biomarkers.Circulating eNampt and resistin, and their kinetics may represent useful diagnostic and prognostic biomarkers in critically ill septic patients. More prospective studies are needed to elucidate their ontological and pathophysiological role in sepsis.