The term Hereditary Non-Polyposis Colorectal Cancer (HNPCC) is a poor descriptor of the syndrome described by Lynch. Over the last decade, the term has been applied to heterogeneous groups of families meeting limite...The term Hereditary Non-Polyposis Colorectal Cancer (HNPCC) is a poor descriptor of the syndrome described by Lynch. Over the last decade, the term has been applied to heterogeneous groups of families meeting limited clinical criteria, for example the Amsterdam criteria. It is now apparent that not all Amsterdam criteria-positive families have the Lynch syndrome. The term HNPCC has also been applied to clinical scenarios in which CRCs with DNA microsateUite instability are diagnosed but in which there is no vertical transmission of an altered DNA mismatch repair (MMR) gene. A term that has multiple, mutually incompatible meanings is highly problematic, particularly when it may influence the management of an individual family. The Lynch syndrome is best understood as a hereditary predisposition to malignancy that is explained by a germline mutation in a DNA MMR gene. The diagnosis does not depend in an absolute sense on any particular family pedigree structure or age of onset of malignancy. Families with a strong family history of colorectal cancer that do not have Lynch syndrome have been grouped as ‘Familial Colorectal Cancer Type-X'. The first step in characterizing these cancer families is to distinguish them from Lynch syndrome. The term HNPCC no longer serves any useful purpose and should be phased out.展开更多
AIM: To analyze the frequency of hereditary non-polyposis colorectal cancer (HNPCC) in Chinese colorectal cancer (CRC) patients, and to discuss the value of microsatellite instability (MSI) and/or immunohistoch...AIM: To analyze the frequency of hereditary non-polyposis colorectal cancer (HNPCC) in Chinese colorectal cancer (CRC) patients, and to discuss the value of microsatellite instability (MSI) and/or immunohistochemistry (IHC) for MSH2/MLH1 protein analysis as pre-screening tests in China. METHODS: The Amsterdam criteria Ⅰ and Ⅱ (clinical diagnosis) and/or germline hMLHI/hMSH2 mutations (genetic diagnosis) were used to classify HNPCC families. Genetic tests, including microsatellite instability, immunohistochemistry for MSH2/MLH1 proteins and hMSH2/hMLH1 genes, were performed in each proband. RESULTS: From July 2000 to June 2004, 1988 patients with colorectal cancer were analysed and 114 CRC patients (5.7%) from 48 families were categorized as having HNPCC, including 76 from 26 families diagnosed clinically and 38 from the other 22 families diagnosed genetically. The sensitivity and specificity of high MSI and IHC for predicting mutations were 100% and 54%, and 79% and 77%, respectively. CONCLUSION: The frequency of HNPCC is approximately 10% among all Chinese CRC cases. The MSI and IHC detections for hMSH2/hMLH1 proteins are reliable prescreening tests for hMLHI/hMSH2 germline mutations in families suspected of having HNPCC.展开更多
AIM: To analyze the prevalence of germline MLH1 and MSH2 gene mutations and evaluate the clinical characteristics of Hungarian hereditary non-polyposis colorectal cancer (HNPCC) families. METHODS: Thirty-six kindreds ...AIM: To analyze the prevalence of germline MLH1 and MSH2 gene mutations and evaluate the clinical characteristics of Hungarian hereditary non-polyposis colorectal cancer (HNPCC) families. METHODS: Thirty-six kindreds were tested for mutations using conformation sensitive gel electrophoreses, direct sequencing and also screening for genomic rearrangements applying multiplex ligation-dependent probe amplifi cation (MLPA). RESULTS: Eighteen germline mutations (50%) were identifi ed, 9 in MLH1 and 9 in MSH2. Sixteen of these sequence alterations were considered pathogenic, the remaining two were non-conservative missense alterations occurring at highly conserved functional motifs. The majority of the defi nite pathogenic mutations (81%, 13/16) were found in families fulfilling the stringent Amsterdam Ⅰ/Ⅱ criteria, including three rearrangements revealed by MLPA (two in MSH2 and one in MLH1). However, in three out of sixteen HNPCC-suspected families (19%), a disease-causing alteration could be revealed. Furthermore, nine mutations described here are novel, and none of the sequence changes were found in more than one family.CONCLUSION: Our study describes for the f irst time the prevalence and spectrum of germline mismatch repair gene mutations in Hungarian HNPCC and suspected-HNPCC families. The results presented here suggest that clinical selection criteria should be relaxed and detection of genomic rearrangements should be included in genetic screening in this population.展开更多
AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients. METHODS: Three hundred and forty H...AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients. METHODS: Three hundred and forty HNPCC mismatch repair (MMR) mutation carriers from the Creighton University Hereditary Cancer Institute Registry were selected for modeling. Age-dependent curves were generated to elucidate the joint effects between gene mutation (hMLH1 or hMSH2), gender, and smoking status on the probability of developing CRC. RESULTS: Smoking significantly increased CRC risk in male hMSH2 mutation carriers (P 〈 0.05). hMLH1 mutations augmented CRC risk relative to hMSH2 mutation carriers for males (P 〈 0.05). Males had a significantly higher risk of CRC than females for hMLH1 non smokers (P 〈 0.05), hMLH1 smokers (P 〈 0.1) and hMSH2 smokers (P 〈 0.1). Smoking promoted CRC in a dose-dependent manner in hMSH2 in males (P 〈 0.05). Females with hMSH2 mutations and both sexes with the hMLH1 groups only demonstrated a smoking effect after an extensive smoking history (P 〈 0.05). CONCLUSION: CRC promotion by smoking in HNPCC patients is dependent on gene mutation, gender and age. These data demonstrate that fuzzy modeling may enable formulation of clinical risk scores, thereby allowing individualization of CRC prevention strategies.展开更多
Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as "Ly...Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as "Lynch syndrome". It is the most common hereditary form of cancer accounting for 5%-10% of all colon cancers. HNPCC is a dominant autosomal genetic disorder caused by germ line mutations in mismatch repair genes. Human mismatch repair genes play a crucial role in genetic stability of DNA, the inactivation of which results in an increased rate of mutation and often a loss of mismatch repair function. Recent studies have shown that certain mismatch repair genes are involved in the regulation of key cellular processes including apoptosis. Thus, differential expression of mismatch repair genes particularly the contributions of MLH1 and MSH2 play important roles in therapeutic resistance to certain cytotoxic drugs such as cisplatin that is used normally as chemoprevention. An understanding of the role of mismatch repair genes in molecular signaling mechanism of apoptosis and its involvement in HNPCC needs attention for further work into this important area of cancer research, and this review article is intended to accomplish that goal of linkage of apoptosis with HNPCC. The current review was not intended to provide a comprehensive enumeration of the entire body of literature in the area of HNPCC or mismatch repair system or apoptosis; it is rather intended to focus primarily on the current state of knowledge of the role of mismatch repair proteins in molecular signaling mechanism of apoptosis as it relates to understanding of HNPCC.展开更多
AIM: To detect the MLH1 gene promoter germline- methylation in probands of Chinese hereditary non- polyposis colorectal cancer (HNPCC), and to evaluate the role of methylation in MLH1 gene promoter and molecular ge...AIM: To detect the MLH1 gene promoter germline- methylation in probands of Chinese hereditary non- polyposis colorectal cancer (HNPCC), and to evaluate the role of methylation in MLH1 gene promoter and molecular genetics in screening for HNPCC.METHODS: The promoter germline methylation of MLH1 gene was detected by methylation-specific PCR (MSP) in 18 probands from unrelated HNPCC families with high microsatellite-instability (MSI-H) phenotype but without germline mutations in MSH2, MLH1 and MSH6 genes. At the same time, 6 kindreds were col- lected with microsatellite-stability (MSS) phenotype but without germline mutations in MSH2, MIH1 and MSH6 genes as controls. The results of MSP were confirmed by clone sequencing. To ensure the reliability of the results, family H65 with nonsense germline mutation at c.2228C 〉 A in MSH2 gene was used as the negative control and the cell line sw48 was used as the known positive control along with water as the blank control. Immunochemical staining of MIH1 protein was performed with Envision two-step method in those patients with aberrant methylation to judge whether the status of MLH1 gene methylation affects the expression of MLH1 protein.RESULTS: Five probands with MIH1 gene promoter methylation were detected in 18 Chinese HNPCC families with MSI-H phenotype but without germline mutations in MSH2, MLH1 and MSH6 genes. Two of the five probands from families H10 and H29 displayed exhaustive-methylation, fulfilling the Japanese criteria (JC) and the Amsterdam criteria (AC), respectively. The other 3 probands presented part-methylation fulfilling the AC. Of the 13 probands with unmethylation phenotype, 8 fulfilled the JC and the Bethesda guidelines (BG), 5 fulfilled the AC. The rate of aberrant methylation in MLH1 gene in the AC group (22.2%, 4/18) was higher than that in the JC/BG groups (5.6%, 1/18) in all HNPCC families with MSI-H phenotype but without germline mutations in PISH2, PIIH1 and MSH6 genes. However, no proband with methylation in MLH1 gene was found in the families with MSS phenotype and without germline mutations in MSH2, MLH1 and MSH6 genes. No expression of MLH1 protein was found in tumor tissues from two patients with exhaustive-methylation phenotype, whereas positive expression of MLH1 protein was observed in tumor tissues from patients with partial methylation phenotype (excluding family H42 without tumor tissue), indicating that exhaustive-methylation of MLH1 gene can cause defective expression of MLH1 protein.CONCLUSION: Methylation phenotype of MLH1 gene is correlated with microsatellite phenotype of MMR genes, especially with MSI-H. Exhaustive-methylation of MLH1 gene can silence the expression of MLH1 protein. MLH1 promoter methylation analysis is a promising tool for molecular genetics screening for HNPCC.展开更多
AIM: To investigate the germline mutations of MSH6 gene in probands of Chinese hereditary non-polyposis colorectal cancer (HNPCC) families fulfilling different clinical criteria. METHODS: Germline mutations of MSH6 ge...AIM: To investigate the germline mutations of MSH6 gene in probands of Chinese hereditary non-polyposis colorectal cancer (HNPCC) families fulfilling different clinical criteria. METHODS: 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. To further investigate the pathological effects of detected missense mutations, we analyzed the above related MSH6 exons using PCR-based sequencing in 137 healthy persons with no family history. The clinicopathological features were collected from the Archive Library of Cancer Hospital, Fudan University and analyzed. RESULTS: Four germline missense mutations distributed in the 4th, 6th and 9th exons were observed. Of them, three were not found in international HNPCC databases and did not occur in 137 healthy controls, indicating that they were novel missense mutations. The remaining mutation which is consistent with the case H14 at c.3488A>T of exon 6 of MSH6 gene was also found in the controls, the rate was approximately 3.65% (5/137) and the type of mutation was not found in the international HNPCC mutational and SNP databases, suggesting that this missense mutation was a new SNP unreported up to date. CONCLUSION: Three novel missense mutations and a new SNP observed in the probands of Chinese HNPCC families, may play an important role in the development of HNPCC.展开更多
AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore t...AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore the pertinent test methods. METHODS: A systematic analysis of 30 probands from HNPCC families in the north of China was performed by immunohistochemistry, microsatellite instability (MSI), gene mutation and methylation detection. RESULTS: High frequency microsatellite instability occurred in 25 probands (83.3%) of HNPCC family. Loss of hMLH1 and hMSH2 protein expression accounted for 88% of all microsatellite instability. Pathogenic muta-tion occurred in 14 samples and 3 novel mutational sites were discovered. Deletion of exons 1-6, 1-7 and 8 of hMSH2 was detected in 3 samples and no large fragment deletion was found in hMLH1. Of the 30 probands, hMLH1 gene promoter methylation occurred in 3 probands. The rate of gene micromutation detection combined with large fragment deletion detection was 46.7%-56.7%. The rate of the two methods in combination with methylation detection was 63.3%. CONCLUSION: Scientific and rational detection strategy can improve the detection rate of HNPCC. Based on traditional molecular genetics and combined with epigenetics, multiple detection methods can accurately diagnose HNPCC.展开更多
Objective To study the clinicopathological features of the Chinese hereditary non-polyposis colorectal cancer and its germline mutation of hMLH1 and hMSH2. Methods Thirteen typical Chinese hereditary non-polyposis col...Objective To study the clinicopathological features of the Chinese hereditary non-polyposis colorectal cancer and its germline mutation of hMLH1 and hMSH2. Methods Thirteen typical Chinese hereditary non-polyposis colorectal carcinoma (HNPC) C kindreds and 19 nontypical HNPCC families were registered and followed up. The germline mutation of the hMLH1 and hMSH2 of 12 index cases of 6 typical and 6 nontypical NHPCC were screened by PCR-SSCP. Samples with abnormal mobility were sequenced direcdy. Results The average age of typical HNPCC was 47, no difference existed between sexs. Location of the tumors of typical HNPCC represented 44.7% on the right half colon and non-typical HNPCC 65. 8% on the rectum. The rate of the metachronos cancer was 11.5%. The 3 - , 5 - and 10 -year survival rate was 64. 0%, 45. 3% and 31. 2% respectively. Among 12 cases, 8 showed abnormal mobility. Except for an intron polymorphinism, six exons abnormalities were found in 5 of 12 proband. Sequencing showed 4 missense,7展开更多
Hereditary non-polyposis colorectal cancer(HNPCC) was previously synonymous with Lynch syndrome; however,identification of the role of germline mutations in the DNA mismatch repair(MMR) genes has made it possible to d...Hereditary non-polyposis colorectal cancer(HNPCC) was previously synonymous with Lynch syndrome; however,identification of the role of germline mutations in the DNA mismatch repair(MMR) genes has made it possible to differentiate Lynch syndrome from other conditions associated with familial colorectal cancer(CRC). Broadly,HNPCC may be dichotomized into conditions that demonstrate defective DNA MMR and microsatellite instability(MSI) vs those conditions that demonstrate intact DNA MMR. Conditions characterized by MMR deficient CRCs include Lynch syndrome(germline MMR mutation),Lynch-like syndrome(biallelic somatic MMR mutations),constitutional MMR deficiency syndrome(biallelic germline MMR mutations),and sporadic MSI CRC(somatic biallelic methylation of MLH1). HNPCC conditions with intact DNA MMR associated with familial CRC include polymerase proofreading associated polyposis and familial colorectal cancer type X. Although next generation sequencing technologies have elucidated the genetic cause for some HNPCC conditions,others remain genetically undefined. Differentiating between Lynch syndrome and the other HNPCC disorders has profound implications for cancer risk assessment and surveillance of affected patients and their at-risk relatives. Clinical suspicion coupled with molecular tumor analysis and testing for germline mutations can help differentiate the clinical mimicry within HNPCC and facilitate diagnosis and management.展开更多
BACKGROUND Individuals with Lynch syndrome(LS)and hereditary non-polyposis colorectal cancer(HNPCC)are at increased risk of both colorectal cancer and other cancers.The interplay between immunosuppression,a comorbid i...BACKGROUND Individuals with Lynch syndrome(LS)and hereditary non-polyposis colorectal cancer(HNPCC)are at increased risk of both colorectal cancer and other cancers.The interplay between immunosuppression,a comorbid inflammatory condition(CID),and HNPCC on cancer risk is unclear.AIM To evaluate the impact of CIDs,and exposure to monoclonal antibodies and immunomodulators,on cancer risk in individuals with HNPCC.METHODS Individuals prospectively followed in a hereditary cancer registry with LS/HNPCC with the diagnosis of inflammatory bowel disease or rheumatic disease were identified.We compared the proportion of patients with cancer in LS/HNPCC group with and without a CID.We also compared the proportion of patients who developed cancer following a CID diagnosis based upon exposure to immunosuppressive medications.RESULTS A total of 21 patients with LS/HNPCC and a CID were compared to 43 patients with LS/HNPCC but no CID.Cancer occurred in 84.2% with a CID compared to 76.7% without a CID(P=0.74)with no difference in age at first cancer diagnosis 45.5±14.6 vs 43.8±7.1 years(P=0.67).LS specific cancers were diagnosed in 52.4% with a CID vs 44.2% without a CID(P=0.54).Nine of 21(42.9%)patients were exposed to biologics or immunomodulators for the treatment of their CID.Cancer after diagnosis of CID was seen in 7(77.8%)of exposed individuals vs 5(41.7%)individuals unexposed to biologics/immunomodulators(P=0.18).All 7 exposed compared to 3/5 unexposed developed a LS specific cancer.The exposed and unexposed groups were followed for a median 10 years and 8.5 years,respectively.The hazard ratio for cancer with medication exposure was 1.59(P=0.43,95%CI:0.5-5.1).CONCLUSION In patients with LS/HNPCC,the presence of a concurrent inflammatory condition,or use of immunosuppressive medication to treat the inflammatory condition,might not increase the rate of cancer occurrence in this limited study.展开更多
目的 :考察遗传性非息肉病性结直肠癌 (HNPCC)家系 h ML H1 /h MSH2生殖系突变的情况。 方法 :选择 1 3个符合Amsterdam标准的 HNPCC家系中的先证者 ,利用 DNA测序检测 h ML H1 /h MSH2基因突变情况。对其中不携带 h ML H1 /h MSH2生殖...目的 :考察遗传性非息肉病性结直肠癌 (HNPCC)家系 h ML H1 /h MSH2生殖系突变的情况。 方法 :选择 1 3个符合Amsterdam标准的 HNPCC家系中的先证者 ,利用 DNA测序检测 h ML H1 /h MSH2基因突变情况。对其中不携带 h ML H1 /h MSH2生殖系突变的 HNPCC家系 ,利用免疫组化检测 h ML H1 /h MSH2基因表达、PCR- SSCP检测先证者肿瘤组织的微卫星不稳定性 (MSI)。 结果 :1 3个 HNPCC家系的先证者中有 3例检测不到 h ML H1 /h MSH2的生殖系突变。 3例无 h ML H1 /h MSH2突变的先证者中 ,肿瘤组织的微卫星不稳定检测均为 MSI- H,免疫组化检测 h ML H1 /h MSH2基因表达正常。结论 :3个严格符合 Amsterdam标准的 HNPCC家系中未发现 h ML H1 /h MSH2基因系突变 ,提示可能存在其他基因突变导致该 3个家系展开更多
Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common form of hereditary colorectal cancer. Although great advances in the understanding of its molecular basis have taken...Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common form of hereditary colorectal cancer. Although great advances in the understanding of its molecular basis have taken place in the last decade, optimal selection of individuals for HNPCC genetic testing remains controversial. This is especially relevant since colonoscopy has been proven effective for reducing colorectal cancer incidence and mortality in individuals at-risk for this disorder. In this manuscript, we summarize the most significant contributions to this important issue that have appearedin the last few years.展开更多
文摘The term Hereditary Non-Polyposis Colorectal Cancer (HNPCC) is a poor descriptor of the syndrome described by Lynch. Over the last decade, the term has been applied to heterogeneous groups of families meeting limited clinical criteria, for example the Amsterdam criteria. It is now apparent that not all Amsterdam criteria-positive families have the Lynch syndrome. The term HNPCC has also been applied to clinical scenarios in which CRCs with DNA microsateUite instability are diagnosed but in which there is no vertical transmission of an altered DNA mismatch repair (MMR) gene. A term that has multiple, mutually incompatible meanings is highly problematic, particularly when it may influence the management of an individual family. The Lynch syndrome is best understood as a hereditary predisposition to malignancy that is explained by a germline mutation in a DNA MMR gene. The diagnosis does not depend in an absolute sense on any particular family pedigree structure or age of onset of malignancy. Families with a strong family history of colorectal cancer that do not have Lynch syndrome have been grouped as ‘Familial Colorectal Cancer Type-X'. The first step in characterizing these cancer families is to distinguish them from Lynch syndrome. The term HNPCC no longer serves any useful purpose and should be phased out.
基金Supported in part by Tianjin Science Grant,China
文摘AIM: To analyze the frequency of hereditary non-polyposis colorectal cancer (HNPCC) in Chinese colorectal cancer (CRC) patients, and to discuss the value of microsatellite instability (MSI) and/or immunohistochemistry (IHC) for MSH2/MLH1 protein analysis as pre-screening tests in China. METHODS: The Amsterdam criteria Ⅰ and Ⅱ (clinical diagnosis) and/or germline hMLHI/hMSH2 mutations (genetic diagnosis) were used to classify HNPCC families. Genetic tests, including microsatellite instability, immunohistochemistry for MSH2/MLH1 proteins and hMSH2/hMLH1 genes, were performed in each proband. RESULTS: From July 2000 to June 2004, 1988 patients with colorectal cancer were analysed and 114 CRC patients (5.7%) from 48 families were categorized as having HNPCC, including 76 from 26 families diagnosed clinically and 38 from the other 22 families diagnosed genetically. The sensitivity and specificity of high MSI and IHC for predicting mutations were 100% and 54%, and 79% and 77%, respectively. CONCLUSION: The frequency of HNPCC is approximately 10% among all Chinese CRC cases. The MSI and IHC detections for hMSH2/hMLH1 proteins are reliable prescreening tests for hMLHI/hMSH2 germline mutations in families suspected of having HNPCC.
基金Supported by the Hungarian Research Grants OTKA T-046570, NKFPI-00024/2005 and ETT 397/2006
文摘AIM: To analyze the prevalence of germline MLH1 and MSH2 gene mutations and evaluate the clinical characteristics of Hungarian hereditary non-polyposis colorectal cancer (HNPCC) families. METHODS: Thirty-six kindreds were tested for mutations using conformation sensitive gel electrophoreses, direct sequencing and also screening for genomic rearrangements applying multiplex ligation-dependent probe amplifi cation (MLPA). RESULTS: Eighteen germline mutations (50%) were identifi ed, 9 in MLH1 and 9 in MSH2. Sixteen of these sequence alterations were considered pathogenic, the remaining two were non-conservative missense alterations occurring at highly conserved functional motifs. The majority of the defi nite pathogenic mutations (81%, 13/16) were found in families fulfilling the stringent Amsterdam Ⅰ/Ⅱ criteria, including three rearrangements revealed by MLPA (two in MSH2 and one in MLH1). However, in three out of sixteen HNPCC-suspected families (19%), a disease-causing alteration could be revealed. Furthermore, nine mutations described here are novel, and none of the sequence changes were found in more than one family.CONCLUSION: Our study describes for the f irst time the prevalence and spectrum of germline mismatch repair gene mutations in Hungarian HNPCC and suspected-HNPCC families. The results presented here suggest that clinical selection criteria should be relaxed and detection of genomic rearrangements should be included in genetic screening in this population.
基金Supported by a grant from the American College of Gastroenterology
文摘AIM: To investigate whether a fuzzy logic model could predict colorectal cancer (CRC) risk engendered by smoking in hereditary non-polyposis colorectal cancer (HNPCC) patients. METHODS: Three hundred and forty HNPCC mismatch repair (MMR) mutation carriers from the Creighton University Hereditary Cancer Institute Registry were selected for modeling. Age-dependent curves were generated to elucidate the joint effects between gene mutation (hMLH1 or hMSH2), gender, and smoking status on the probability of developing CRC. RESULTS: Smoking significantly increased CRC risk in male hMSH2 mutation carriers (P 〈 0.05). hMLH1 mutations augmented CRC risk relative to hMSH2 mutation carriers for males (P 〈 0.05). Males had a significantly higher risk of CRC than females for hMLH1 non smokers (P 〈 0.05), hMLH1 smokers (P 〈 0.1) and hMSH2 smokers (P 〈 0.1). Smoking promoted CRC in a dose-dependent manner in hMSH2 in males (P 〈 0.05). Females with hMSH2 mutations and both sexes with the hMLH1 groups only demonstrated a smoking effect after an extensive smoking history (P 〈 0.05). CONCLUSION: CRC promotion by smoking in HNPCC patients is dependent on gene mutation, gender and age. These data demonstrate that fuzzy modeling may enable formulation of clinical risk scores, thereby allowing individualization of CRC prevention strategies.
基金Supported by NSF-EPSCoR P3 Center and NASA-EOSCoR Research Infrastructure Development Funds to Ali N
文摘Colorectal cancer is the second most leading cause of cancer related deaths in the western countries. One of the forms of colorectal cancer is hereditary non-polyposis colorectal cancer (HNPCC), also known as "Lynch syndrome". It is the most common hereditary form of cancer accounting for 5%-10% of all colon cancers. HNPCC is a dominant autosomal genetic disorder caused by germ line mutations in mismatch repair genes. Human mismatch repair genes play a crucial role in genetic stability of DNA, the inactivation of which results in an increased rate of mutation and often a loss of mismatch repair function. Recent studies have shown that certain mismatch repair genes are involved in the regulation of key cellular processes including apoptosis. Thus, differential expression of mismatch repair genes particularly the contributions of MLH1 and MSH2 play important roles in therapeutic resistance to certain cytotoxic drugs such as cisplatin that is used normally as chemoprevention. An understanding of the role of mismatch repair genes in molecular signaling mechanism of apoptosis and its involvement in HNPCC needs attention for further work into this important area of cancer research, and this review article is intended to accomplish that goal of linkage of apoptosis with HNPCC. The current review was not intended to provide a comprehensive enumeration of the entire body of literature in the area of HNPCC or mismatch repair system or apoptosis; it is rather intended to focus primarily on the current state of knowledge of the role of mismatch repair proteins in molecular signaling mechanism of apoptosis as it relates to understanding of HNPCC.
基金Supported by Shanghai Medical Development Fund for Major Projects, No. 05III004Shanghai Pujiang Projects for Talents, No. 06PJ14019
文摘AIM: To detect the MLH1 gene promoter germline- methylation in probands of Chinese hereditary non- polyposis colorectal cancer (HNPCC), and to evaluate the role of methylation in MLH1 gene promoter and molecular genetics in screening for HNPCC.METHODS: The promoter germline methylation of MLH1 gene was detected by methylation-specific PCR (MSP) in 18 probands from unrelated HNPCC families with high microsatellite-instability (MSI-H) phenotype but without germline mutations in MSH2, MLH1 and MSH6 genes. At the same time, 6 kindreds were col- lected with microsatellite-stability (MSS) phenotype but without germline mutations in MSH2, MIH1 and MSH6 genes as controls. The results of MSP were confirmed by clone sequencing. To ensure the reliability of the results, family H65 with nonsense germline mutation at c.2228C 〉 A in MSH2 gene was used as the negative control and the cell line sw48 was used as the known positive control along with water as the blank control. Immunochemical staining of MIH1 protein was performed with Envision two-step method in those patients with aberrant methylation to judge whether the status of MLH1 gene methylation affects the expression of MLH1 protein.RESULTS: Five probands with MIH1 gene promoter methylation were detected in 18 Chinese HNPCC families with MSI-H phenotype but without germline mutations in MSH2, MLH1 and MSH6 genes. Two of the five probands from families H10 and H29 displayed exhaustive-methylation, fulfilling the Japanese criteria (JC) and the Amsterdam criteria (AC), respectively. The other 3 probands presented part-methylation fulfilling the AC. Of the 13 probands with unmethylation phenotype, 8 fulfilled the JC and the Bethesda guidelines (BG), 5 fulfilled the AC. The rate of aberrant methylation in MLH1 gene in the AC group (22.2%, 4/18) was higher than that in the JC/BG groups (5.6%, 1/18) in all HNPCC families with MSI-H phenotype but without germline mutations in PISH2, PIIH1 and MSH6 genes. However, no proband with methylation in MLH1 gene was found in the families with MSS phenotype and without germline mutations in MSH2, MLH1 and MSH6 genes. No expression of MLH1 protein was found in tumor tissues from two patients with exhaustive-methylation phenotype, whereas positive expression of MLH1 protein was observed in tumor tissues from patients with partial methylation phenotype (excluding family H42 without tumor tissue), indicating that exhaustive-methylation of MLH1 gene can cause defective expression of MLH1 protein.CONCLUSION: Methylation phenotype of MLH1 gene is correlated with microsatellite phenotype of MMR genes, especially with MSI-H. Exhaustive-methylation of MLH1 gene can silence the expression of MLH1 protein. MLH1 promoter methylation analysis is a promising tool for molecular genetics screening for HNPCC.
基金Supported by Shanghai Medical Development Fund for Major Projects, No. 05Ⅲ004 and Shanghai Pu Jiang Projects for Talented-Men, 06PJ14019
文摘AIM: To investigate the germline mutations of MSH6 gene in probands of Chinese hereditary non-polyposis colorectal cancer (HNPCC) families fulfilling different clinical criteria. METHODS: 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. To further investigate the pathological effects of detected missense mutations, we analyzed the above related MSH6 exons using PCR-based sequencing in 137 healthy persons with no family history. The clinicopathological features were collected from the Archive Library of Cancer Hospital, Fudan University and analyzed. RESULTS: Four germline missense mutations distributed in the 4th, 6th and 9th exons were observed. Of them, three were not found in international HNPCC databases and did not occur in 137 healthy controls, indicating that they were novel missense mutations. The remaining mutation which is consistent with the case H14 at c.3488A>T of exon 6 of MSH6 gene was also found in the controls, the rate was approximately 3.65% (5/137) and the type of mutation was not found in the international HNPCC mutational and SNP databases, suggesting that this missense mutation was a new SNP unreported up to date. CONCLUSION: Three novel missense mutations and a new SNP observed in the probands of Chinese HNPCC families, may play an important role in the development of HNPCC.
基金Supported by Beijing Natural Science Foundation, No. 7062064
文摘AIM: To study the characteristics of mismatch repair gene mutation of Chinese hereditary non-polyposis colorectal cancer (HNPCC) and hMLH1 gene promoter methylation, and to improve the screening strategy and explore the pertinent test methods. METHODS: A systematic analysis of 30 probands from HNPCC families in the north of China was performed by immunohistochemistry, microsatellite instability (MSI), gene mutation and methylation detection. RESULTS: High frequency microsatellite instability occurred in 25 probands (83.3%) of HNPCC family. Loss of hMLH1 and hMSH2 protein expression accounted for 88% of all microsatellite instability. Pathogenic muta-tion occurred in 14 samples and 3 novel mutational sites were discovered. Deletion of exons 1-6, 1-7 and 8 of hMSH2 was detected in 3 samples and no large fragment deletion was found in hMLH1. Of the 30 probands, hMLH1 gene promoter methylation occurred in 3 probands. The rate of gene micromutation detection combined with large fragment deletion detection was 46.7%-56.7%. The rate of the two methods in combination with methylation detection was 63.3%. CONCLUSION: Scientific and rational detection strategy can improve the detection rate of HNPCC. Based on traditional molecular genetics and combined with epigenetics, multiple detection methods can accurately diagnose HNPCC.
文摘Objective To study the clinicopathological features of the Chinese hereditary non-polyposis colorectal cancer and its germline mutation of hMLH1 and hMSH2. Methods Thirteen typical Chinese hereditary non-polyposis colorectal carcinoma (HNPC) C kindreds and 19 nontypical HNPCC families were registered and followed up. The germline mutation of the hMLH1 and hMSH2 of 12 index cases of 6 typical and 6 nontypical NHPCC were screened by PCR-SSCP. Samples with abnormal mobility were sequenced direcdy. Results The average age of typical HNPCC was 47, no difference existed between sexs. Location of the tumors of typical HNPCC represented 44.7% on the right half colon and non-typical HNPCC 65. 8% on the rectum. The rate of the metachronos cancer was 11.5%. The 3 - , 5 - and 10 -year survival rate was 64. 0%, 45. 3% and 31. 2% respectively. Among 12 cases, 8 showed abnormal mobility. Except for an intron polymorphinism, six exons abnormalities were found in 5 of 12 proband. Sequencing showed 4 missense,7
基金Supported by The United States Public Health Service(DK067287 and CA162147)the A.Alfred Taubman Medical Research Institute of the University of Michigan
文摘Hereditary non-polyposis colorectal cancer(HNPCC) was previously synonymous with Lynch syndrome; however,identification of the role of germline mutations in the DNA mismatch repair(MMR) genes has made it possible to differentiate Lynch syndrome from other conditions associated with familial colorectal cancer(CRC). Broadly,HNPCC may be dichotomized into conditions that demonstrate defective DNA MMR and microsatellite instability(MSI) vs those conditions that demonstrate intact DNA MMR. Conditions characterized by MMR deficient CRCs include Lynch syndrome(germline MMR mutation),Lynch-like syndrome(biallelic somatic MMR mutations),constitutional MMR deficiency syndrome(biallelic germline MMR mutations),and sporadic MSI CRC(somatic biallelic methylation of MLH1). HNPCC conditions with intact DNA MMR associated with familial CRC include polymerase proofreading associated polyposis and familial colorectal cancer type X. Although next generation sequencing technologies have elucidated the genetic cause for some HNPCC conditions,others remain genetically undefined. Differentiating between Lynch syndrome and the other HNPCC disorders has profound implications for cancer risk assessment and surveillance of affected patients and their at-risk relatives. Clinical suspicion coupled with molecular tumor analysis and testing for germline mutations can help differentiate the clinical mimicry within HNPCC and facilitate diagnosis and management.
文摘BACKGROUND Individuals with Lynch syndrome(LS)and hereditary non-polyposis colorectal cancer(HNPCC)are at increased risk of both colorectal cancer and other cancers.The interplay between immunosuppression,a comorbid inflammatory condition(CID),and HNPCC on cancer risk is unclear.AIM To evaluate the impact of CIDs,and exposure to monoclonal antibodies and immunomodulators,on cancer risk in individuals with HNPCC.METHODS Individuals prospectively followed in a hereditary cancer registry with LS/HNPCC with the diagnosis of inflammatory bowel disease or rheumatic disease were identified.We compared the proportion of patients with cancer in LS/HNPCC group with and without a CID.We also compared the proportion of patients who developed cancer following a CID diagnosis based upon exposure to immunosuppressive medications.RESULTS A total of 21 patients with LS/HNPCC and a CID were compared to 43 patients with LS/HNPCC but no CID.Cancer occurred in 84.2% with a CID compared to 76.7% without a CID(P=0.74)with no difference in age at first cancer diagnosis 45.5±14.6 vs 43.8±7.1 years(P=0.67).LS specific cancers were diagnosed in 52.4% with a CID vs 44.2% without a CID(P=0.54).Nine of 21(42.9%)patients were exposed to biologics or immunomodulators for the treatment of their CID.Cancer after diagnosis of CID was seen in 7(77.8%)of exposed individuals vs 5(41.7%)individuals unexposed to biologics/immunomodulators(P=0.18).All 7 exposed compared to 3/5 unexposed developed a LS specific cancer.The exposed and unexposed groups were followed for a median 10 years and 8.5 years,respectively.The hazard ratio for cancer with medication exposure was 1.59(P=0.43,95%CI:0.5-5.1).CONCLUSION In patients with LS/HNPCC,the presence of a concurrent inflammatory condition,or use of immunosuppressive medication to treat the inflammatory condition,might not increase the rate of cancer occurrence in this limited study.
文摘目的 :考察遗传性非息肉病性结直肠癌 (HNPCC)家系 h ML H1 /h MSH2生殖系突变的情况。 方法 :选择 1 3个符合Amsterdam标准的 HNPCC家系中的先证者 ,利用 DNA测序检测 h ML H1 /h MSH2基因突变情况。对其中不携带 h ML H1 /h MSH2生殖系突变的 HNPCC家系 ,利用免疫组化检测 h ML H1 /h MSH2基因表达、PCR- SSCP检测先证者肿瘤组织的微卫星不稳定性 (MSI)。 结果 :1 3个 HNPCC家系的先证者中有 3例检测不到 h ML H1 /h MSH2的生殖系突变。 3例无 h ML H1 /h MSH2突变的先证者中 ,肿瘤组织的微卫星不稳定检测均为 MSI- H,免疫组化检测 h ML H1 /h MSH2基因表达正常。结论 :3个严格符合 Amsterdam标准的 HNPCC家系中未发现 h ML H1 /h MSH2基因系突变 ,提示可能存在其他基因突变导致该 3个家系
基金Ministerio de Educación y Ciencia (SAF 04-07190 and 07/-64873) from the Asociación Espaola contra el Cáncer, the Hospital Clínic and Fondo de Investigación Sanitaria
文摘Lynch syndrome, also known as hereditary non-polyposis colorectal cancer (HNPCC), is the most common form of hereditary colorectal cancer. Although great advances in the understanding of its molecular basis have taken place in the last decade, optimal selection of individuals for HNPCC genetic testing remains controversial. This is especially relevant since colonoscopy has been proven effective for reducing colorectal cancer incidence and mortality in individuals at-risk for this disorder. In this manuscript, we summarize the most significant contributions to this important issue that have appearedin the last few years.