AIM: To examine the mechanism of inactivation of the p16 gene in gallbladder cancer,and to investigate p16 alterations and their correlation with clinicopathological features. METHODS: Specimens were collected surgica...AIM: To examine the mechanism of inactivation of the p16 gene in gallbladder cancer,and to investigate p16 alterations and their correlation with clinicopathological features. METHODS: Specimens were collected surgically from 51 patients with gallbladder cancer. We evaluated the status of protein expression,loss of heterozygosity (LOH),homozygous deletion and promoter hypermethylation using immunohistochemistry,microsatellite analysis,quantitative real-time polymerase chain reaction (PCR) and methylation-specific PCR,respectively. In addition,mutations were examined by direct DNA sequencing. RESULTS: Homozygous deletions of the p16 gene exon2,LOH at 9p21-22,p16 promoter hypermethylation,and loss of p16 protein expression were detected in 26.0% (13/50),56.9% (29/51),72.5% (37/51) and 62.7% (32/51),respectively. No mutations were found. LOH at 9p21 correlated with the loss of p16 protein expression (P < 0.05). Homozygous deletion of the p16 gene,a combination LOH and promoter hypermethylation,and multiple LOH at 9p21 were significantly correlated with the loss of p16 protein expression (P < 0.05). LOH at 9p21 and promoter hypermethylation of the p16 gene were detected in 15.4% (2/13) and 92.3% (12/13) of the tumors with homozygous deletion of the p16 gene,respectively. P16 alterations were not associated with clinicopathological features. CONCLUSION: Our results suggest that LOH and homozygous deletion may be two distinct pathways in the inactivation of the p16 gene. Homozygous deletion,a combination of LOH and promoter hypermethylation,and multiple LOH are major mechanisms of p16 inactivation in gallbladder cancer.展开更多
Cystic fibrosis, a common autosomal recessive genetic disorder among Caucasians, is caused by defects in the transmembrane conductance regulatory(CFTR) gene. The analysis of CFTR gene mutations is useful to better cha...Cystic fibrosis, a common autosomal recessive genetic disorder among Caucasians, is caused by defects in the transmembrane conductance regulatory(CFTR) gene. The analysis of CFTR gene mutations is useful to better characterize the disease, and for preconceptional screening, prenatal and preimplantation genetic diagnosis. Here we report the results of a genetic analysis in a 16-year-old boy from southwestern Iran diagnosed as having cystic fibrosis in infancy based on gastrointestinal and pulmonary manifestations, with positive sweat chloride tests. He lacked both normal and mutant forms of the fragment corresponding to the F508 allele in initial genetic studies. Multiplex ligationdependent probe amplification-based testing revealed a homozygous deletion spanning exons 4 to 10 of the CFTR gene. We predict an in-frame deletion removing 373 amino acids based on our sequencing results. Determining CFTR gene mutations in patients and their family members would be helpful to prevent the occurrence of new cases, especially in populations in which consanguinity is common.展开更多
目的:研究胰腺癌细胞基因组范围内的纯合性缺失和杂合性缺失(loss of heterozygosity,LOH).方法:应用高密度单核苷酸多态性芯片和专用分析软件,检测17种胰腺癌细胞株基因组范围内的纯合性缺失和LOH,并筛选可能与胰腺癌发生、发展有关的...目的:研究胰腺癌细胞基因组范围内的纯合性缺失和杂合性缺失(loss of heterozygosity,LOH).方法:应用高密度单核苷酸多态性芯片和专用分析软件,检测17种胰腺癌细胞株基因组范围内的纯合性缺失和LOH,并筛选可能与胰腺癌发生、发展有关的基因区域,用PCR验证纯合性缺失.结果:经过PCR验证,26个区域确实为纯合性缺失,芯片的准确度为83.9%(26/31).这些缺失区域中,平均每个区域只涉及1.29个基因.每一种细胞都有不同程度的LOH;不同染色体臂出现LOH频率不同,出现频率最高的为染色体臂9p和18q,均为94.1%.结论:胰腺癌全基因组范围内出现多处LOH和纯合性缺失,这些区域可能含有新抑癌基因.展开更多
文摘AIM: To examine the mechanism of inactivation of the p16 gene in gallbladder cancer,and to investigate p16 alterations and their correlation with clinicopathological features. METHODS: Specimens were collected surgically from 51 patients with gallbladder cancer. We evaluated the status of protein expression,loss of heterozygosity (LOH),homozygous deletion and promoter hypermethylation using immunohistochemistry,microsatellite analysis,quantitative real-time polymerase chain reaction (PCR) and methylation-specific PCR,respectively. In addition,mutations were examined by direct DNA sequencing. RESULTS: Homozygous deletions of the p16 gene exon2,LOH at 9p21-22,p16 promoter hypermethylation,and loss of p16 protein expression were detected in 26.0% (13/50),56.9% (29/51),72.5% (37/51) and 62.7% (32/51),respectively. No mutations were found. LOH at 9p21 correlated with the loss of p16 protein expression (P < 0.05). Homozygous deletion of the p16 gene,a combination LOH and promoter hypermethylation,and multiple LOH at 9p21 were significantly correlated with the loss of p16 protein expression (P < 0.05). LOH at 9p21 and promoter hypermethylation of the p16 gene were detected in 15.4% (2/13) and 92.3% (12/13) of the tumors with homozygous deletion of the p16 gene,respectively. P16 alterations were not associated with clinicopathological features. CONCLUSION: Our results suggest that LOH and homozygous deletion may be two distinct pathways in the inactivation of the p16 gene. Homozygous deletion,a combination of LOH and promoter hypermethylation,and multiple LOH are major mechanisms of p16 inactivation in gallbladder cancer.
基金Supported by Shiraz University of Medical Sciences,Shiraz,Iran and Bologna University,Bologna,Italy
文摘Cystic fibrosis, a common autosomal recessive genetic disorder among Caucasians, is caused by defects in the transmembrane conductance regulatory(CFTR) gene. The analysis of CFTR gene mutations is useful to better characterize the disease, and for preconceptional screening, prenatal and preimplantation genetic diagnosis. Here we report the results of a genetic analysis in a 16-year-old boy from southwestern Iran diagnosed as having cystic fibrosis in infancy based on gastrointestinal and pulmonary manifestations, with positive sweat chloride tests. He lacked both normal and mutant forms of the fragment corresponding to the F508 allele in initial genetic studies. Multiplex ligationdependent probe amplification-based testing revealed a homozygous deletion spanning exons 4 to 10 of the CFTR gene. We predict an in-frame deletion removing 373 amino acids based on our sequencing results. Determining CFTR gene mutations in patients and their family members would be helpful to prevent the occurrence of new cases, especially in populations in which consanguinity is common.
文摘目的:研究胰腺癌细胞基因组范围内的纯合性缺失和杂合性缺失(loss of heterozygosity,LOH).方法:应用高密度单核苷酸多态性芯片和专用分析软件,检测17种胰腺癌细胞株基因组范围内的纯合性缺失和LOH,并筛选可能与胰腺癌发生、发展有关的基因区域,用PCR验证纯合性缺失.结果:经过PCR验证,26个区域确实为纯合性缺失,芯片的准确度为83.9%(26/31).这些缺失区域中,平均每个区域只涉及1.29个基因.每一种细胞都有不同程度的LOH;不同染色体臂出现LOH频率不同,出现频率最高的为染色体臂9p和18q,均为94.1%.结论:胰腺癌全基因组范围内出现多处LOH和纯合性缺失,这些区域可能含有新抑癌基因.
