中文摘要：

目的 了解抑癌基因PTEN在乳腺癌组织中的突变频率和突变类型，探讨PTEN突变与散发性乳腺癌的关系。方法 应用聚合酶链反应一单链构象多态性分析（PCR-SSCP）方法以及DNA测序技术，扩增45例散发性乳腺癌PTEN基因的9个外显子，根据构象改变检测其基因突变情况。结果 45例乳腺癌组织中检测到1例外显子2第24位密码子由A-C的错义突变，突变使蛋白结构由甲硫氨酸突变为亮氨酸。结论 散发性乳腺癌中存在PTEN抑癌基因的突变，但突变率很低。

英文摘要：

Objective To detect the mutation frequency and mutation type of tumor suppressor PTEN in sporadic breast carcinoma tissues, and to investigate the association of PTEN gene mutation and sporadic breast cancer. Methods Polymerase chain reaction-single strand conformation polymorphism （PCR-SSCP） was used to amplify 9 exons of PTEN and to analyze the conformation polymorphism, then DNA sequencing methods was used to detect point mutation of PTEN gene nine exons of abnormal single strand conformation in breast carcinoma. Results One of 45 cases showed 24th condon A→C missense mutation in the exon2 of PTEN gene, and this mutation made Met to change to Ala in PTEN protein structure. Conclusion These data indicated the existence of PTEN mutation in sporadic breast cancer, but PTEN gene mutation rate is very low.