即时荧光定量PCR微卫星分析技术检测少突胶质细胞肿瘤染色体1p/19q杂合性缺失

目的研究少突胶质细胞肿瘤染色体1p／19q杂合性缺失（LOH）情况。方法采用即时荧光定量PCR微卫星分析技术对28例少突胶质细胞肿瘤进行染色体1p／19qLOH检测。结果28例少突胶质细胞肿瘤染色体中有24例（85．7％）发生1pLOH;有18例（64．3％）发生19qLOH;有17例（60．7％）发生1p／19q联合性LOH;25例有1P或19qLOH。结论即时荧光定量PCR微卫星分析技术特异性高、方便快捷,可以用于石蜡包埋组织标本染色体杂合性缺失的检测。大多数少突胶质细胞肿瘤发生了1p／19qLOH。     

少突胶质细胞瘤中PTEN基因突变和10q 染色体的杂合性缺失分析

目的 探讨PTEN基因突变和10q染色体的杂合性缺失(LOH)在少突胶质细胞瘤发生和发展中的意义。方法 以55例少突胶质细胞瘤和混合性胶质细胞瘤为研究对象，PCR扩增PTEN基因所有9个外显子，其产物经变性梯度凝胶电泳(DGGE)后，DNA序列分析检测PTEN基因突变。应用不同颜色荧光标记10q微卫星标志物引物，PCR扩增后，其产物在自动测序仪上进行聚丙烯酰胺凝胶电泳，用Gene Scan软件分析LOH。结果 2／55例有PTEN基因突变，1例是PTEN的第9外显子的20号T碱基缺失导致终止密码351易位至347，另1例在139位发生C到A的转换，使得Phe变成Leu。23／55(42％)例出现染色体10q的LOH，其中15／55例位于10q^23.3(D10S541)，其为PTEN基因位点，12／55例10q微卫星标志物位点完全缺失。结论 在少突胶质细胞瘤中PTEN突变较少见，而10q LOH较频繁，尤其在恶性度高的少突胶质细胞瘤中表现明显，提示10q LOH与少突胶质细胞瘤恶性进展有关，且10q上可能存在其他抑癌基因。     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

少突胶质细胞瘤染色体1p/19 q杂合性缺失与p53蛋白表达的相关性研究

目的 探讨少突胶质细胞瘤染色体1p/19q杂合性缺失及p53蛋白的表达情况,与星形细胞起源的肿瘤进行比较研究并探讨其意义.方法 选择2004-2005年间,经病理组织学诊断为不同类型和级别的胶质瘤合计191例,包括:WHOⅡ级少突胶质细胞瘤116例,其中30例为新鲜组织;间变性少突胶质细胞瘤45例和不同级别星形细胞起源的肿瘤石蜡组织30例;采用PCR-微卫星技术检测染色体1p/19q杂合性缺失情况;采用免疫组织化学方法 对184例胶质瘤石蜡切片p53蛋白表达情况进行半定量分析.结果 86例WHO Ⅱ级少突胶质细胞瘤石蜡标本染色体1p缺失率为69.8%(60/86)、19q缺失率为64.0%(55/86)、1p/19q联合缺失率为57.0%(49/86);45例间变性少突胶质细胞瘤中,1p缺失率为71.1%(32/45)、19q缺失率为60.0%(27/45)、1p/19q联合缺失率为55.6%(25/45);两种级别间差异无统计学意义(P>0.05).30例WHO Ⅱ级少突胶质细胞瘤新鲜标本染色体1p缺失率为70.0%(21/30)、19q缺失率为63.3%(19/30)、1p/19q联合缺失率为60.0%(18/30),与石蜡标本的缺失率比较差异无统计学意义(P>0.05).30例星形细胞起源的肿瘤染色体对应三种缺失率分别为23.3%(7/30)、33.3%(10/30)及20.0%(6/30),与少突胶质细胞瘤差异有统计学意义(P<0.05).86例WHO Ⅱ级少突胶质细胞瘤中,仅7例有p53蛋白阳性表达(占8.1%);45例间变性少突胶质细胞瘤中,有14例呈阳性表达(31.1%),两者差异有统计学意义(P=0.007).少突胶质细胞瘤p53蛋白阳性表达明显低于星形细胞起源的肿瘤(P=0.001).在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关(P<0.05).结论 石蜡和新鲜组织均可用于染色体1p/19q杂合性缺失的检测.在间变性少突胶质细胞瘤中,染色体1p/19q杂合性缺失与p53蛋白阳性表达呈负相关.检测少突胶质细胞瘤染色体1p/19q杂合性缺失和p53蛋白表达,对提高病理诊断的精确性、指导治疗及预后判断具有重要意义.     

Oligodendroglial tumors: refinement of candidate regions on chromosome arm 1p and correlation of 1p/19q status with survival

Loss of heterozygosity (LOH) on the chromosome arms 1p and 19q is frequent in oligodendroglial tumors and has been correlated with chemosensitivity and good prognosis in anaplastic oligodendrogliomas. The oligodendroglioma-associated tumor suppressor genes on 1p and 19q are as yet unknown. To narrow down candidate regions on 1p, we investigated oligodendroglial tumors from 89 patients for LOH at up to 30 polymorphic loci on 1p. In addition, all tumors were studied for LOH at 7 loci on 19q. Combined LOH on 1p and 19q was detected in 20 (83%) of 24 oligodendrogliomas, 15(63%) of 24 anaplastic oligodendrogliomas, 10 (56%) of 18 oligoastrocytomas, and 12 (52%) of 23 anaplastic oligoastrocytomas. Five tumors demonstrated partial deletions on 1p, which allowed to define 3 distinct candidate regions at 1p36.31-pter distal to D1S2633, 1p36.22-p36.31 between D1S489 and D1S2642, and 1p34.2-p36.1 between D1S2743 and D1S482, respectively. No partial deletions were detected on 19q. Combined LOH on 1p and 19q was associated with prolonged time to progression (TTP), longer overall survival (OS), and a higher 5-year survival rate. Depending on the presence or absence of combined LOH on 1p and 19q, patients with anaplastic oligodendroglial tumors treated with adjuvant radio- and/or chemotherapy showed a median TTP of 86 months versus 39 months, a median OS of 91 months versus 46 months, and a 5-year survival rate of 80% versus 36%, respectively. Similarly, LOH on 1p and 19q was associated with longer survival in patients with low-grade oligodendroglial tumors (TTP: 57 months versus 47 months; OS: 172 months versus 105 months; 5-year survival rate: 92% versus 70%). Thus, our results refine the location of putative oligodendroglioma suppressor genes on 1p and support the significance of LOH on 1p and 19q as a favorable prognostic marker.     

Age-related differences in 1p and 19q deletions in oligodendrogliomas

BACKGROUND: Recent reports indicate that anaplastic oligodendrogliomas frequently show allelic losses on chromosome arms 1p and 19q, and that these deletions are associated with better chemotherapeutic response and overall patient survival. Because of the diversified genetic makeup of the population and the centralized provincial referral system for brain tumor patients in Manitoba, the epidemiological features of such tumors sometimes differ from the published data acquired from non-community based settings. In this study, we assessed the prevalence of allelic deletions for chromosome arms 1p and 19q in anaplastic and in low-grade oligodendrogliomas in the Manitoba population. METHODS: Loss of heterozygosity (LOH) analysis of brain tumors was carried out using 4 microsatellite markers (D1S508, D1S2734, D19S219 and D19S412) and a PCR based assay. The tumors were consecutively acquired during the period September 1999-March 2001 and a total of 63 tumors were assessed. RESULTS: We found that allelic loss of chromosome 1p and 19q was higher in oligodendrogliomas than in other diffuse gliomas and that for anaplastic oligodendrogliomas, younger patients exhibited significantly more deletions than older patients (>60 years of age). CONCLUSIONS: These studies suggest that age may be a factor in the genetic alterations of oligodendrogliomas. In addition, these studies demonstrate that this assay can easily be carried out in a cost-effective manner in a small tertiary center.     

Clinical significance of chromosome 1p/19q loss of heterozygosity and Sox17 expression in oligodendrogliomas

Objective: To study chromosome 1p/19q loss of heterozygosity (LOH) and Sox17 protein expression in oligodendrogliomas and correlate this loss with clinicopathological features. Methods: This study included 100 cases of oligodendrogliomas at the First Affiliated Hospital of Xinjiang Medical University from 2003 to 2014. The cases included paraffin-embedded tissues from 50 low-grade oligodendrogliomas and 50 anaplastic oligodendrogliomas. Chromosome 1p/19q LOH was detected by fluorescence in situ hybridization (FISH) and Sox17 protein expression was analyzed by immunohistochemistry. Clinicopathological characteristics of the oligodendrogliomas were compared and prognosis analyzed using Cox regression and Kaplan-Meier analyses. Results: The LOH positivity rate of 1p/19q was 52% in 50 cases of low-grade oligodendrogliomas and 68% in 50 cases of anaplastic oligodendrogliomas (P = 0.102). The rates of Sox17 expression were significantly different in oligodendrogliomas (82%) and anaplastic oligodendrogliomas (62%, P = 0.026). Single factor analysis determined that 1p/19q LOH (P = 0.000), Sox17 protein expression (P = 0.000), location (P = 0.001), chemotherapy (P = 0.000), and radiation therapy (P = 0.001) were associated with oligodendroglioma patient prognosis. Cox multiple factors regression analysis determined that 1p/19q LOH and Sox17 expression were independent prognostic factors of oligodendrogliomas. Conclusion: In this study, oligodendroglioma patients with 1p/19q LOH and Sox17 protein expression had a better prognosis. Thus, analysis of 1p/19q LOH and Sox17 protein expression could significantly enhance diagnostic accuracy, guide treatment, and improve the prognosis.     

Screening for loss of heterozygosity and microsatellite instability in oligodendrogliomas

To assess the frequency of loss of heterozygosity (LOH) and microsatellite instability (MI) in oligodendrogliomas, we performed an extensive screening of 16 oligodendrogliomas and nine anaplastic oligodendrogliomas by using 132 microsatellite markers on chromosomes 1 through 12 and 15 through 21. In total, 3,135 loci were examined in 25 tumor samples. Only 33/1,965 (1.7%) of oligodendroglioma (low-grade) and 11/1,070 (1.0%) of anaplastic oligodendroglioma (high-grade) loci exhibited MI. High-frequency LOH regions were identified on chromosome arms 1p (31–73% for oligodendrogliomas and 60–100% for anaplastic oligodendrogliomas) and 19q (23–69% for oligodendrogliomas and 100% for anaplastic oligodendrogliomas). In addition, regions on chromosomes 4, 6, and 11 were found to be lost in 30–80% of both oligodendrogliomas and anaplastic oligodendrogliomas. Increased LOH frequency of chromosome 17 (38–40%) was found only in high-grade oligodendrogliomas. The differences in LOH frequencies between low-grade and high-grade oligodendrogliomas in all loci combined and at three loci (D1S447, D1S226, and D1S252) on chromosome arm 1p were determined to be statistically significant [χ²(1) = 20.2, P < 0.0001, and Fisher's exact test respective P values: 0.01, 0.03, and 0.02]. Our results provide evidence that microsatellite instability does not play an important role in the development of oligodendrogliomas. Furthermore, high LOH frequency on chromosomes 6 and 11 in addition to that identified previously on chromosomes 1, 19, and 4 suggests that multiple candidate tumor suppressor genes on these chromosomes may underlie the processes of initiation and/or progression in oligodendroglioma tumorigenesis. Genes Chromosomes Cancer 21:207–216, 1998. © 1998 Wiley-Liss, Inc.     

Molecular Genetic Aspects of Oligodendrogliomas Including Analysis by Comparative Genomic Hybridization

Oligodendroglial neoplasms are a subgroup of gliomas with distinctive morphological characteristics. In the present study we have evaluated a series of these tumors to define their molecular profiles and to determine whether there is a relationship between molecular genetic parameters and histological pattern in this tumor type. Loss of heterozygosity (LOH) for 1p and 19q was seen in 17/23 (74%) well-differentiated oligodendrogliomas, in 18/23 (83%) anaplastic oligodendrogliomas, and in 3/8 (38%) oligoastrocytomas grades II and III. LOH for 17p and/or mutations of the TP53 gene occurred in 14 of these 55 tumors. Only one of the 14 cases with 17p LOH/TP53 gene mutation also had LOH for 1p and 19q, and significant astrocytic elements were seen histologically in the majority of these 14 tumors. LOH for 9p and/or deletion of the CDKN2A gene occurred in 15 of these 55 tumors, and 11 of these cases were among the 24 (42%) anaplastic oligodendrogliomas. Comparative genomic hybridization (CGH) identified the majority of cases with 1p and 19q loss and, in addition, showed frequent loss of chromosomes 4, 14, 15, and 18. These findings demonstrate that oligodendroglial neoplasms usually have loss of 1p and 19q whereas astrocytomas of the progressive type frequently contain mutations of the TP53 gene, and that 9p loss and CDKN2A deletions are associated with progression from well-differentiated to anaplastic oligodendrogliomas.     

Region-specific loss of heterozygosity on chromosome 19 is related to the morphologic type of human glioma

Allelic mutation on chromosome 19 has previously been reported as a frequent genetic event in human glial tumors. In an effort to localize specific regions of importance on this chromosome better, 13 highly polymorphic genetic markers distributed along the length of chromosome 19 were used for evaluation of loss of heterozygosity (LOH) and microsatellite instability in a total of 100 brain tumors, including 75 astrocytomas (55 grade 4; 7 grade 3; 5 grade 2; 6 grade 1; and 2 other), 17 oligodendrogliomas (1 grade 4; 5 grade 3; 10 grade 2; and 1 grade 1), and 8 mixed oligoastrocytomas (MOA) (3 grade 4; 2 grade 3; and 3 grade 2). No microsatellite expansion was observed in these glial tumors for any of the chromosome 19 loci examined. LOH for loci on chromosome 19 was detected in 23/74 informative astrocytomas (31%), 11/17 oligodendrogliomas (65%), and 3/8 MOA (38%). Partial deletion of chromosome 19 occurred more frequently (31/37 cases) than did loss of one whole copy of the chromosome, and a morphology-specific pattern of LOH was observed. In 12/14 (86%) instances of chromosome 19 deletion in oligodendrogliomas and MOA, the 19q arm showed LOH, whereas the 19p arm showed no loss for all informative loci. Conversely, in 17/23 (74%) instances of chromosome 19 deletion in astrocytomas, the 19p arm showed LOH, whereas the 19q arm showed no loss for one or more loci. Thus, loss of 19q and retention of 19p are strongly associated with oligodendroglioma and MOA, whereas loss of 19p and retention of distal 19q is associated with astrocytoma. These data indicate that two or more tumor suppressor genes may reside on chromosome 19, one on 19p important in the development of astrocytomas, and one on 19q important in oligodendrogliomas and MOA.     

Allelic status of 1p and 19q in oligodendrogliomas and glioblastomas: multiplex ligation-dependent probe amplification versus loss of heterozygosity

Identification of the 1p/19q allelic status in gliomas, primarily those with a major oligodendroglial component, has become an excellent molecular complement to tumor histology in order to identify those cases sensitive to chemotherapy. In addition to loss of heterozygosity (LOH), fluorescence in situ hybridization (FISH), or comparative genomic hybridization (CGH), multiplex ligation-dependent probe amplification (MLPA) has been shown to be an alternative methodology to identify deletions of those chromosome arms. We used MLPA to explore the 1p and 19q allelic constitution in a series of 76 gliomas: 41 tumors with a major oligodendroglial component, 34 glioblastomas, and one low-grade astrocytoma. We compared the MLPA findings of the oligodendroglial cases with those previously obtained using LOH in the same samples. Thirty-eight of 41 oligodendrogliomas displayed identical findings by both LOH and MLPA, and losses at either 1p and/or 19q were identified in 12 of 35 (34%) astrocytic tumors. These findings agree with data previously reported comparing MLPA versus FISH or CGH in gliomas and suggest that MLPA can be used in the identification of the 1p/19q allelic deletions on these brain neoplasms     

Acquisition of the Glioblastoma Phenotype during Astrocytoma Progression Is Associated with Loss of Heterozygosity on 10q25-qter

Loss of heterozygosity on chromosome 10 (LOH#10) is the most frequent genetic alteration in glioblastomas and occurs in more than 80% of cases. We recently reported that PTEN (MMAC1) on 10q23.3 is mutated in approximately 30% of primary (de novo) glioblastomas but rarely in secondary glioblastomas that progressed from low-grade or anaplastic astrocytomas. Because secondary glioblastomas also show LOH#10, tumor suppressor genes other than PTEN are likely to be involved. We analyzed LOH on chromosomes 10 and 19, using polymorphic microsatellite markers in microdissected foci showing histologically an abrupt transition from low-grade or anaplastic astrocytoma to glioblastoma, suggestive of the emergence of a new tumor clone. When compared to the respective low-grade or anaplastic astrocytoma of the same biopsy, deletions were detected in 7 of 8 glioblastoma foci on 10q25-qter distal to D10S597, covering the DMBT1 and FGFR2 loci. Six of 8 foci showed LOH at one or two flanking markers of PTEN but did not contain PTEN mutations. LOH on 10p and 19q was found in only one case each. These data indicate that acquisition of a highly anaplastic glioblastoma phenotype with marked proliferative activity and lack of glial fibrillary acidic protein expression is associated with loss of a putative tumor suppressor gene on 10q25-qter.