AIM: To study the germline mutation of hPMS2 gene in 26 unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese. METHODS: Genomic DNA was...AIM: To study the germline mutation of hPMS2 gene in 26 unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese. METHODS: Genomic DNA was extracted from the peripheral blood. To avoid the interference of pseudogene in detection of the remaining 11 exons (exon 1-5, 9, 11-15), long-range polymerase chain reaction (PCR) was conducted to amplify the complete coding region of hPMS2 gene firstly. Then 1/8 of the PCR productswere used as template to amplify the individual exon respectively and DNA sequencing was done. Direct DNA sequencing of the conventional PCR products of exon 6, 7, 8 and 10 of hPMS2 gene was performed. The same analysis was made in 130 healthy persons without family histories of HNPCC to further investigate the pathological effects of the detected missense mutation. RESULTS: One HNPCC proband fulf illed Bethesda guidelines and was found to carry the germline mutation of hPMS2 gene, which has not been reported in Chinese HNPCC families. It was a missense mutation at c.1532C>T of exon 11. It was detected in three controls as well with an occurrence rate of 2.3% (3/130). Since it could not be found in the PMS2-single nucleotide polymorphism (SNP) database, this missense mutation is a new SNP unreported up to date. Meanwhile, 260 reported SNPs of hPMS2 gene were detected in the 26 HNPCC probands. The 2nd and 5th exons were probably the hot SNP regions of hPMS2 gene in Chinese HNPCC families involving 53.1% of all reported SNP. CONCLUSION: The germline mutation of hPMS2 gene may be rare in Chinese HNPCC families. The 2nd and 5th exons are hot SNP regions of hPMS2 gene.展开更多
AIM: To describe systematically the clinical characteristics and phenotype of HNPCC families and the prevalence of HNPCC in the general population of CRC patients in China. METHODS: HNPCC kindreds and CRC patients wer...AIM: To describe systematically the clinical characteristics and phenotype of HNPCC families and the prevalence of HNPCC in the general population of CRC patients in China. METHODS: HNPCC kindreds and CRC patients were from two sources. One was that we consecutively investigated kindreds and patients by ourselves. And the other was the published Chinese and foreign literature related to Chinese HNPCC syndrome. There were 142 HNPCC families fulfilling AC I and/or AC II including 57 families with detailed data, and 3874 general primary CRC patients in all. All statistical tests were two-sided. RESULTS: In AC I families, the number of Lynch syndrome I and II families were 25 (47.2%) and 28 (52.8%) respectively. There were 215 patients (82.4%) with CRC, 67 patients (25.7%) with extracolonic cancer and 50 patients (19.2%) with multiple primary cancers. In all CRC patients, multiple primary CRC were in 41 patients (19.1%), and the first-CRC was right-sided colorectal cancer in 143 patients (66.5%) and rectal cancer in 44 patients (20.5%). 8.8% and 19.2% of the first cancer were CRC and extracolonic cancers. Among those patients whose first cancer was CRC, 66.8% and 19.9% were right-sided colorectal cancer and rectal cancer, respectively. The similar results were found in AC II families. Normal distribution was only found in the distribution of the age of diagnosis of the first cancer in both AC I families (coefficient of skewness: u = 0.81, 0.20<0.40<P<0.50; coefficient of kurtosis: u = 1.13, 0.20<P<0.40,α=0.20) and AC II families (coefficient of skewness: u=0.63, P>0.5> 0.20; coefficient of kurtosis: u = 0.84, 0.20<0.40<P<0.50, α=0.20), but not found in the distribution of the age of diagnosis of the first CRC. When patients with HNPCC-associated cancer suffered from the first malignant tumor in HNPCC families diagnosed by AC I and AC II, the mean age and median age were 45.1±12.7 years and 44.0 years, 45.2±12.7 years and 44.5 years, respectively. The median age of diagnosis of the first tumor of the patients in the later generation was younger than that in the previous generation. Many extracolonic cancers were found to be associated with HNPCC syndrome. Gastric cancer was the most frequent extracolonic cancer followed by endometrial cancer and hepatocarcinoma. In general population of CRC patients, the prevalence of HNPCC diagnosed by AC I and AC II were 1.3% and 2.2%, respectively. CONCLUSION: The clinical phenotype and prevalence of Chinese HNPCC syndrome are similar to those of Europeans and Americans. Gastric cancer is the most common extracolonic malignant tumor. The age of diagnosis of the first malignant tumor tends to be increasingly younger in patients with HNPCC-related tumors.展开更多
AIM： To analyze the clinical characteristics of Chinese hereditary nonpolyposis colorectal cancer （HNPCC） families and to screen the germline mutations of human mismatch repair genes hMLH1 and hMSH2 in the probands...AIM： To analyze the clinical characteristics of Chinese hereditary nonpolyposis colorectal cancer （HNPCC） families and to screen the germline mutations of human mismatch repair genes hMLH1 and hMSH2 in the probands. METHODS： Thirty-one independent Chinese HNPCC families were collected in Zhejiang Province. All of them met Chinese HNPCC criteria. Clinical data about patient gender, site of colorectal cancer, age of onset, history of multiple colorectal cancer, associated extracolonic cancer were recorded. PCR and denaturing high performance liquid chromatography （DHPLC） were employed to screen the mutations. Sequencing analysis was used to find out the exact mutation site and characteristics of the samples showing abnormal DHPLC profiles. RESULTS： One hundred and thirty-six malignant neoplasms were found in 107 patients including 14 multiple cancers. One hundred and six of the 136 neoplasms （77.9%） were diagnosed as colorectal cancer, with an average age of onset at 48.57 ±29.00 years. Gastric cancer was the most common extracolonic cancer （10.3%） in these families. Twenty-three different sequence variations in hMLHI and hMSH2 genes were detected in these 17 families. Fifteen sequence variations were located in the exons, including 5 SNPs, 3 silent mutations, 3 missense mutations, 2 nonsense mutations and 2 frameshift mutations. The latter seven mutations seemed to be pathogenic. CONCLUSION： Germline mutations of hMLH1 and hMSH2 genes are identified in about one-third HNPCC kindreds fulfilling Chinese HNPCC criteria. Chinese HNPCC families have some particular clinical characteristics, such as a left-sided predominance, less synchronous or metachronous colorectal cancer, and frequent occurrence of gastric cancer.展开更多
AIM： To detect microsatellite instability （MSI） in patients with hereditary nonpolyposis colorectal cancer or ordinary hereditary colorectal cancer and to provide criteria for screening the kindreds with hereditary...AIM： To detect microsatellite instability （MSI） in patients with hereditary nonpolyposis colorectal cancer or ordinary hereditary colorectal cancer and to provide criteria for screening the kindreds with hereditary nonpolyposis colorectal cancer at molecular level.METHODS： MSI was detected in the specimens from 20 cases with HNPCC, 20 cases with ordinary hereditary colorectal cancer and 20 cases with sporadic colorectal cancer by means of polymerase chain reaction-single strand conformation polymorphism. RESULTS： The positive rate of MSI was 85% （17/20） in HNPCC group, 40% （8/20） in ordinary hereditary colorectal cancer group and 10% （2/20） in the sporadic colorectal cancer group respectively. The differences were significant. The mean ages of the three groups were 43.6, 52.2, and 61.8 years respectively, which increased gradually. The incidence of right hemicolon cancer was 64.7%, 37.5%, and 0% respectively, which decreased gradually and had significant difference. The expression ratio of BAT26 and BAT25 was 94.1% respectively, which was highest in the 5 gene sites studied. The incidence of poorly differentiated adenocarcinoma was 70.6% in HNPCC group among high frequency microsatellite instability （MSI-H）, which was higher than the other two groups, which had 50% and 50% respectively. CONCLUSION： The incidence of MSI-H is higher in HNPCC group. The detection of MSI is simple and economical and has high correlation with the clinicopathologic feature of HNPCC and can be used as a screening method to detect the germ line mutation of the mismatch repair gene.展开更多
Objective To 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)...Objective To 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). Methods A 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. Results The 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 (P<0.05). 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 P<0.01]. 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 (P<0.05). In comparison to MMR positive HNPCC carcinoma, HNPCC adenoma, and sporadic carcinoma, COX-2 expression was significantly lower in corresponding MMR-deficient cases (all P<0.05). 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 P<0.05). Conclusion COX-2 is expressed at a low level in HNPCC carcinoma, different from the high COX-2 expression in sporadic carcinoma.展开更多
AIM： To screen a suspected Hungarian HNPCC family to find specific mutations and to evaluate their effect on the presentation of the disease. METHODS： The family was identified by applying the Amsterdam and Bethesda...AIM： To screen a suspected Hungarian HNPCC family to find specific mutations and to evaluate their effect on the presentation of the disease. METHODS： The family was identified by applying the Amsterdam and Bethesda Criteria. Immunohistochemistry was performed, and DNA samples isolated from tumor tissue were evaluated for microsatellite instability. The identification of possible mutations was carried out by sequencing the hMLH1 and hMSH2 genes. RESULTS： Two different mutations were observed in the index patient and in his family members. The first mutation was located in exon 7, codon 422 of hMSH2, and caused a change from Glu to STOP codon. No other report of such a mutation has been published, as far as we could find in the international databases. The second mutation was found in exon 3 codon 127 of the hMSH2 gene, resulting in Asp→Ser substitution. The second mutation was already published, as a non-pathogenic allelic variation. CONCLUSION： The pedigree analysis suggested that the newly detected nonsense mutation in exon 7 of the hMSH2 gene might be responsible for the development of colon cancers. In family members where the exon 7 mutation is not coupled with this missense mutation, colon cancer appears after the age of 40. The association of these two mutations seems to decrease the age of manifestation of the disease into the early thirties.展开更多
Lynch syndrome(LS),also known as hereditary non-polyposis colorectal cancer(HNPCC),is an inherited condition associated with a higher risk of colorectal cancer(CRC)and other cancers.It is caused by germline mutations ...Lynch syndrome(LS),also known as hereditary non-polyposis colorectal cancer(HNPCC),is an inherited condition associated with a higher risk of colorectal cancer(CRC)and other cancers.It is caused by germline mutations in DNA mismatch repair(MMR)genes,including MLH1,MSH2,MSH6 and PMS2.These mutations lead to microsatellite instability(MSI)and defective DNA repair mechanisms,resulting in increased cancer risk.Early detection of LS is crucial for effective management and cancer prevention.Endoscopic surveillance,particularly regular colonoscopy,is recommended for individuals with LS to detect CRC at early stages.Additionally,universal screening of CRC for MMR deficiency can help identify at-risk individuals.Genetic counseling plays a valuable role in LS by guiding patients and their families in understanding the genetic basis,making informed decisions regarding surveillance and prevention,and offering reproductive options to reduce the transmission of pathogenic variants of the offspring.The aim of this review is to outline current strategies for the diagnosis,surveillance,and management of LS,with a focus on the role of genetic counseling,endoscopic screening,and emerging therapeutic approaches to mitigate cancer risk in affected individuals.展开更多
基金Supported by The Initiation Fund for Prominent Young Researchers of Shanghai Medical College,Fudan University
文摘AIM: To study the germline mutation of hPMS2 gene in 26 unrelated Chinese hereditary nonpolyposis colorectal cancer (HNPCC) probands and to fulfill the screening strategy for HNPCC in Chinese. METHODS: Genomic DNA was extracted from the peripheral blood. To avoid the interference of pseudogene in detection of the remaining 11 exons (exon 1-5, 9, 11-15), long-range polymerase chain reaction (PCR) was conducted to amplify the complete coding region of hPMS2 gene firstly. Then 1/8 of the PCR productswere used as template to amplify the individual exon respectively and DNA sequencing was done. Direct DNA sequencing of the conventional PCR products of exon 6, 7, 8 and 10 of hPMS2 gene was performed. The same analysis was made in 130 healthy persons without family histories of HNPCC to further investigate the pathological effects of the detected missense mutation. RESULTS: One HNPCC proband fulf illed Bethesda guidelines and was found to carry the germline mutation of hPMS2 gene, which has not been reported in Chinese HNPCC families. It was a missense mutation at c.1532C>T of exon 11. It was detected in three controls as well with an occurrence rate of 2.3% (3/130). Since it could not be found in the PMS2-single nucleotide polymorphism (SNP) database, this missense mutation is a new SNP unreported up to date. Meanwhile, 260 reported SNPs of hPMS2 gene were detected in the 26 HNPCC probands. The 2nd and 5th exons were probably the hot SNP regions of hPMS2 gene in Chinese HNPCC families involving 53.1% of all reported SNP. CONCLUSION: The germline mutation of hPMS2 gene may be rare in Chinese HNPCC families. The 2nd and 5th exons are hot SNP regions of hPMS2 gene.
文摘AIM: To describe systematically the clinical characteristics and phenotype of HNPCC families and the prevalence of HNPCC in the general population of CRC patients in China. METHODS: HNPCC kindreds and CRC patients were from two sources. One was that we consecutively investigated kindreds and patients by ourselves. And the other was the published Chinese and foreign literature related to Chinese HNPCC syndrome. There were 142 HNPCC families fulfilling AC I and/or AC II including 57 families with detailed data, and 3874 general primary CRC patients in all. All statistical tests were two-sided. RESULTS: In AC I families, the number of Lynch syndrome I and II families were 25 (47.2%) and 28 (52.8%) respectively. There were 215 patients (82.4%) with CRC, 67 patients (25.7%) with extracolonic cancer and 50 patients (19.2%) with multiple primary cancers. In all CRC patients, multiple primary CRC were in 41 patients (19.1%), and the first-CRC was right-sided colorectal cancer in 143 patients (66.5%) and rectal cancer in 44 patients (20.5%). 8.8% and 19.2% of the first cancer were CRC and extracolonic cancers. Among those patients whose first cancer was CRC, 66.8% and 19.9% were right-sided colorectal cancer and rectal cancer, respectively. The similar results were found in AC II families. Normal distribution was only found in the distribution of the age of diagnosis of the first cancer in both AC I families (coefficient of skewness: u = 0.81, 0.20<0.40<P<0.50; coefficient of kurtosis: u = 1.13, 0.20<P<0.40,α=0.20) and AC II families (coefficient of skewness: u=0.63, P>0.5> 0.20; coefficient of kurtosis: u = 0.84, 0.20<0.40<P<0.50, α=0.20), but not found in the distribution of the age of diagnosis of the first CRC. When patients with HNPCC-associated cancer suffered from the first malignant tumor in HNPCC families diagnosed by AC I and AC II, the mean age and median age were 45.1±12.7 years and 44.0 years, 45.2±12.7 years and 44.5 years, respectively. The median age of diagnosis of the first tumor of the patients in the later generation was younger than that in the previous generation. Many extracolonic cancers were found to be associated with HNPCC syndrome. Gastric cancer was the most frequent extracolonic cancer followed by endometrial cancer and hepatocarcinoma. In general population of CRC patients, the prevalence of HNPCC diagnosed by AC I and AC II were 1.3% and 2.2%, respectively. CONCLUSION: The clinical phenotype and prevalence of Chinese HNPCC syndrome are similar to those of Europeans and Americans. Gastric cancer is the most common extracolonic malignant tumor. The age of diagnosis of the first malignant tumor tends to be increasingly younger in patients with HNPCC-related tumors.
基金Supported by the Subdivisional Project of the "863" High Technology Research and Program of China, No. 2001AA227111
文摘AIM： To analyze the clinical characteristics of Chinese hereditary nonpolyposis colorectal cancer （HNPCC） families and to screen the germline mutations of human mismatch repair genes hMLH1 and hMSH2 in the probands. METHODS： Thirty-one independent Chinese HNPCC families were collected in Zhejiang Province. All of them met Chinese HNPCC criteria. Clinical data about patient gender, site of colorectal cancer, age of onset, history of multiple colorectal cancer, associated extracolonic cancer were recorded. PCR and denaturing high performance liquid chromatography （DHPLC） were employed to screen the mutations. Sequencing analysis was used to find out the exact mutation site and characteristics of the samples showing abnormal DHPLC profiles. RESULTS： One hundred and thirty-six malignant neoplasms were found in 107 patients including 14 multiple cancers. One hundred and six of the 136 neoplasms （77.9%） were diagnosed as colorectal cancer, with an average age of onset at 48.57 ±29.00 years. Gastric cancer was the most common extracolonic cancer （10.3%） in these families. Twenty-three different sequence variations in hMLHI and hMSH2 genes were detected in these 17 families. Fifteen sequence variations were located in the exons, including 5 SNPs, 3 silent mutations, 3 missense mutations, 2 nonsense mutations and 2 frameshift mutations. The latter seven mutations seemed to be pathogenic. CONCLUSION： Germline mutations of hMLH1 and hMSH2 genes are identified in about one-third HNPCC kindreds fulfilling Chinese HNPCC criteria. Chinese HNPCC families have some particular clinical characteristics, such as a left-sided predominance, less synchronous or metachronous colorectal cancer, and frequent occurrence of gastric cancer.
文摘AIM： To detect microsatellite instability （MSI） in patients with hereditary nonpolyposis colorectal cancer or ordinary hereditary colorectal cancer and to provide criteria for screening the kindreds with hereditary nonpolyposis colorectal cancer at molecular level.METHODS： MSI was detected in the specimens from 20 cases with HNPCC, 20 cases with ordinary hereditary colorectal cancer and 20 cases with sporadic colorectal cancer by means of polymerase chain reaction-single strand conformation polymorphism. RESULTS： The positive rate of MSI was 85% （17/20） in HNPCC group, 40% （8/20） in ordinary hereditary colorectal cancer group and 10% （2/20） in the sporadic colorectal cancer group respectively. The differences were significant. The mean ages of the three groups were 43.6, 52.2, and 61.8 years respectively, which increased gradually. The incidence of right hemicolon cancer was 64.7%, 37.5%, and 0% respectively, which decreased gradually and had significant difference. The expression ratio of BAT26 and BAT25 was 94.1% respectively, which was highest in the 5 gene sites studied. The incidence of poorly differentiated adenocarcinoma was 70.6% in HNPCC group among high frequency microsatellite instability （MSI-H）, which was higher than the other two groups, which had 50% and 50% respectively. CONCLUSION： The incidence of MSI-H is higher in HNPCC group. The detection of MSI is simple and economical and has high correlation with the clinicopathologic feature of HNPCC and can be used as a screening method to detect the germ line mutation of the mismatch repair gene.
基金Supported by National Natural Science Foundation of China (30940086)
文摘Objective To 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). Methods A 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. Results The 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 (P<0.05). 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 P<0.01]. 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 (P<0.05). In comparison to MMR positive HNPCC carcinoma, HNPCC adenoma, and sporadic carcinoma, COX-2 expression was significantly lower in corresponding MMR-deficient cases (all P<0.05). 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 P<0.05). Conclusion COX-2 is expressed at a low level in HNPCC carcinoma, different from the high COX-2 expression in sporadic carcinoma.
文摘AIM： To screen a suspected Hungarian HNPCC family to find specific mutations and to evaluate their effect on the presentation of the disease. METHODS： The family was identified by applying the Amsterdam and Bethesda Criteria. Immunohistochemistry was performed, and DNA samples isolated from tumor tissue were evaluated for microsatellite instability. The identification of possible mutations was carried out by sequencing the hMLH1 and hMSH2 genes. RESULTS： Two different mutations were observed in the index patient and in his family members. The first mutation was located in exon 7, codon 422 of hMSH2, and caused a change from Glu to STOP codon. No other report of such a mutation has been published, as far as we could find in the international databases. The second mutation was found in exon 3 codon 127 of the hMSH2 gene, resulting in Asp→Ser substitution. The second mutation was already published, as a non-pathogenic allelic variation. CONCLUSION： The pedigree analysis suggested that the newly detected nonsense mutation in exon 7 of the hMSH2 gene might be responsible for the development of colon cancers. In family members where the exon 7 mutation is not coupled with this missense mutation, colon cancer appears after the age of 40. The association of these two mutations seems to decrease the age of manifestation of the disease into the early thirties.
文摘Lynch syndrome(LS),also known as hereditary non-polyposis colorectal cancer(HNPCC),is an inherited condition associated with a higher risk of colorectal cancer(CRC)and other cancers.It is caused by germline mutations in DNA mismatch repair(MMR)genes,including MLH1,MSH2,MSH6 and PMS2.These mutations lead to microsatellite instability(MSI)and defective DNA repair mechanisms,resulting in increased cancer risk.Early detection of LS is crucial for effective management and cancer prevention.Endoscopic surveillance,particularly regular colonoscopy,is recommended for individuals with LS to detect CRC at early stages.Additionally,universal screening of CRC for MMR deficiency can help identify at-risk individuals.Genetic counseling plays a valuable role in LS by guiding patients and their families in understanding the genetic basis,making informed decisions regarding surveillance and prevention,and offering reproductive options to reduce the transmission of pathogenic variants of the offspring.The aim of this review is to outline current strategies for the diagnosis,surveillance,and management of LS,with a focus on the role of genetic counseling,endoscopic screening,and emerging therapeutic approaches to mitigate cancer risk in affected individuals.
