PIK3CA基因在乳腺癌不同分子亚型中突变的研究

目的探讨PIK3CA基因在乳腺癌不同分子亚型中突变的关系。方法选取200例乳腺癌患者组织标本，其中luminal A、luminal B、HER-2过表达型、besal-like型各50例。提取DNA，用紫外光分光光度仪来测定浓度及含量，对exon9及exon20进行PCR扩增，扩增产物纯化后测序，另取20例乳腺腺病组织标本用作为对照，与基因库序列对比分析其突变的情况。结果200例乳腺癌组织中发现突变64例，突变率32％，其中exon9突变26例（40％），exon20突变38例（60％），在乳腺癌分子亚型中：luminal A型中22例（44％），luminalB型中16例（32％），HER-2过表达型20例（40％），besal—like型6例（12％），突变分布有统计学意义（P〈0．05）。在20例良性对照组中均没发现突变。PIK3CA基因突变与乳腺癌肿瘤患者肿瘤大小、年龄、淋巴结状态之间无明显相关性（P〉0．05）。结论PIK3CA基因在乳腺癌不同分子亚型中的突变有差异，与乳腺癌其他临床病理特征之间无明显相关性。

Study of PIK3CA Gene Mutation in Different Molecular Subtypes of Breast Cancer

Objective To investigate correlation of PIK3 CA gene mutation in different molecular subtypes of breast cancer. Methods To select 200 cases of breast cancer tissue samples, The luminal subtype A, luminal subtype B, HER-2 over-expression subtype and besal-like subtype all the 50 cases. To extract DNA from samples of breast cancer, PCR amplification of exons 9 and 20 was done after determining the concentration and content by ultraviolet spectrophotometer, followed by sequence after the product was purified. Another 20 samples of adenosis of breast were chosen as controls. Results The frequency of PIK3CA mutations among 200 cases was 64 missense mutations （32%） , 26（40% ） in exon 9, 38（60% ） in exon 20 were found. In molecular subtype of breast cancer：22 （44%） in luminal subtype A , 16 （32%） in luminal subtype B,20（40% ） in HER-2 over-expression subtype, 6（ 12% ） in besal-like subtype, mutations distribution had statistical significance （P 〈 0.05）. No mutation was found in 20 cases of adenosis of breast. The mutation of PIK3CA gene had no significant correlation with age, tumor size and lymph node status（P 〉 0.05）. Conclusion The mutations of PIK3CA gene with different molecular subtypes are different in breast cancer. However, there is no significant correlation between PIK3CA gene mutations and the pathological features of breast carcinoma.