肿瘤抑癌基因PTEN在骨及软组织肿瘤中的突变

Mutation analysis of tumor suppressor gene PTEN in bone and soft tissue tumors

目的 探讨肿瘤抑癌基因PTEN在骨及软组织肿瘤发生中的作用。方法 应用聚合酶链反应 (PCR)分析骨及软组织肿瘤患者 110例肿瘤标本 ,3个肿瘤细胞系PTEN基因第 4～ 9外显子有无纯合性缺失。应用单链构象多态性分析 (SSCP)及基因测序技术观察有无基因突变。对照为瘤旁正常组织。结果 PTEN基因第 4～ 9外显子经扩增后均有产物 ,无基因纯合性缺失改变。SSCP分析未发现变异带 ,无基因突变。但外显子 8表现出两种不同带型 ,该基因存在多态性 ,6例肿瘤在内含子 8距拼接部 32bp处存在两种不同碱基 ,基因型为g/t。结论 在DNA水平肿瘤抑癌基因PTEN在骨及软组织肿瘤的发生中不起作用 ;

Objective To study tumor suppressor gene PTEN′s role in the tumorigenesis of bone and soft tissue tumors. Methods Exon 4～9 of PTEN were amplified by polymerase chain reaction (PCR) for homozygous deletions in 110 tumor samples of patients with bone and soft tissue tumors, 3 tumor cell lines. PTEN mutations were detected by a combination of single strand conformation polymorphism (SSCP) analysis and DNA sequencing. Normal tissue beside tumors was used as control. Results There were always products of amplified exon 4～9 of PTEN, so no homozygous deletions existed. No homozygous deletions presented as variant band was not found by SSCP analysis. Two kinds of band type appeared in exon 8. A g/t polymorphism was found 32 bp from the splice donor site of intron 8 in six tumors. Conclusions At the level of DNA, PTEN mutations do not play major roles in the tumorigenesis of bone and soft tissue tumors. The polymorphism of PTEN gene exists in Chinese people.