散发性乳腺癌中BRCA1和BRCA2基因突变的研究

目的检测BRCA1和BRCA2基因在散发性乳腺癌中的突变情况,探讨BRCA1和BRCA2基因突变与乳腺癌的关系。方法选取2000年12月至2005年9月收治的144例乳腺癌患者标本作实验组,另取非癌乳腺组织标本30例作对照组。用酚-氯仿抽提法提取DNA。针对各个外显子的碱基序列特征,设计有助于筛查基因碱基突变的聚合酶链反应（PCR）引物。每例DNA标本均用PCR扩增BRCA1基因的全部22个外显子和BRCA2基因的exon10和exon14两个外显子。分别将每例外显子的PCR扩增产物进行单链构象多态性分析,对泳动变位或出现异常区带的PCR扩增产物进行DNA测序。结果对照组未检测出BRCA1和BRCA2基因突变,实验组中检测出20例BRCA1基因碱基改变,总突变率为13．9％,其中错义突变率为11．1％。BRCA2基因exon10和exon14未检测出突变。结论BBCA1突变与乳腺癌密切相关,筛查BRCA1基因突变对于中国人群乳腺癌患病风险评估、早期诊断及基因治疗具有重要意义。

Study of BRCA1 and BRCA2 gene mutations in human sporadic breast cancers

Objective To detect the mutations of BRCA1 and BRCA2 in sporadic breast cancer and study the relationship between BRCA1 and BRCA2 mutations and breast cancer. Methods Breast cancer tissues of 144 patients and breast tissues of 30 cases of healthy people who were treated from December 2000 to September 2005 were studied. DNA was extracted by the phenol-chloroform method. Fragmnents of exon2, exon3, exon5, exon6, exon7, exon8, exon9, exonl 0, exonl 1, exonl2, exonl 3, exonl 4, exonlS, exonl 6, exonl 7, exon18,exon19 ,exon20,exon21 ,exon22,exon23 and exon24 in the BRCA1 gene and exonl0 and exon14 in the BRCA2 gene were amplified by polymerase chain reaction. Mutation screening was performed by singlestrand conformation polymorphism analysis and alterations were confirmed by DNA sequencing. Results A total of 20 single nucleotide changes in BRCA1 were detected in the 144 cases of breast cancer patients. The total mutation rate was 13. 9% and missense mutation rate was 11.1%. No mutation was detected in the BRCA2 and controls. Conclusions Mutations in BRCA1 may play an important role in evaluation of sick risk, earlier diagonosis and gene therapy of breast cancer in southern Chinese populations.