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

MUTATION OF PTEN AND LOSS OF HETEROZYGOSITY ON 10q IN OLIGODENDROGLIMAS

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 5 5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GeneScan软件分析LOH。 结果 2 5 5例有PTEN基因突变 ,1例是PTEN的第 9外显子的 2 0号T碱基缺失导致终止密码 35 1易位至 347,另 1例在 139位发生C到A的转换 ,使得Phe变成Leu。 2 3 5 5 (4 2 % )例出现染色体 10q的LOH ,其中 15 / 5 5例位于 10q2 3,3(D10S5 4 1) ,其为PTEN基因位点 ,12 / 5 5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 10qLOH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 10qLOH与少突胶质细胞瘤恶性进展有关 ,且

Objective To detect the PTEN gene mutation and loss of heterozygosity(LOH) on chromosome 10q in oligodendrogliomas. Methods The entire PTEN coding sequence of the 9 exons were screened by 9 different PCR reactions and followed by denaturing gradient gel electrophoresis(DGGE) and direct sequencing for detecte mutation.Microsatellite markers with fluorochrome on 10?q amplified by PCR were used to detecte LOH by PAGE on an automatic sequencer and analyzed with the Gene Scan program in 55 oligodendrogliomas and mixed oligodendrogliomas. Results The PTEN gene somatic mutations were detected in 2 tumors,one case that carried a PTEN mutation deletion T base in position 20 resulting stop codon moved to 347.Another case was a A to C transition at the codon 139 resulting in changeing from Leu to Phe.Twenty\|three of 55(42%) cases were observed the loss of heterozygosity(LOH) on chromosome 10?q.Fifteen of 55 cases allelic loss were detected on loci D10S 541 which located in the PTEN gene region at 10?q 23\^3 .Twelve of 55 cases were detected totaled LOH on 10?q.Conclusion\ The PTEN gene mutation is rare,loss of allelic 10?q is frequente in oligodendrogliomas,especially in high\|grade oligodendrogliomas.It could indicate that LOH on 10?q has an enhance effect in tumor progression,and chromosome 10?q harbors additional tumor suppressor genes in oligodendrogliomas.\;[