摘要
目的 明确在神经母细胞瘤中 p16基因是否发生甲基化及其频率 ,阐明p16基因在神经母细胞瘤中的作用机制。方法 应用PCR技术结合限制性内切酶FnuDⅡ、SacⅡ、HpaⅡ为工具 ,对 14例神经母细胞瘤患者的 14个原发灶及其中 5例肿瘤周围正常组织 p16基因第 1外显子CpG岛进行了甲基化修饰的研究。 结果 5例正常组织的 p16基因第 1外显子CpG岛未发生甲基化 ,而 4例原发灶在Ⅱ (1例 )、Ⅲ (2例 )、Ⅳ (1例 )期有甲基化发生。结论 神经母细胞瘤瘤组织DNA中不存在p16基因的纯合性缺失 ,p16基因甲基化可能为其失活的一种形式 ,Ⅱ、Ⅲ、Ⅳ期均有发生 ,可能是肿瘤发生的早期事件。同一患者的原发灶和转移灶 ,可有不同的甲基化模式 ,反映了肿瘤的异质性。
Objective To investigate whether the hypermethylation of p16 gene is present or not.Method The methylation pattern at 5′ CpG island of p16 gene was analyzed by PCR combined with methylation sensitive restriction endonuclease enzymes Hpa Ⅱ、Sac Ⅱ and FnuDⅡ in the normal tissue in 5 cases and 14 primary tumors and in 2 of which metastatic tumors were available.Results 5′ CpG island methylation occured in 4/14 primary tumors and 1/2 metastatic tumors.no methylation occured in the normal tissue in 5 cases,no homozygous deletions occured in neuroblastomas since all tumor DNA undigested displayed specific bands after PCR amplification.Methylation scattered from stage Ⅱ to stage Ⅳ,both the primary and metastatic DNA display methylation in one Ⅳ stage patient.This indicated that methylation occured prior to metastasis and methylation of CpG island was early event of this tumorigenesis.Conclusions De novo 5′ CpG island methylation of p16 gene is an important and common mode of inactivation for this negative regulator of cell cycle in neuroblastomas.
出处
《苏州医学院学报》
2001年第1期28-31,共4页
Acta Academiae Medicinae Suzhou
