上海地区妇女乳腺癌组织PIK3CA基因热点突变区域研究

Mutational hotspots of PIK3CA in breast cancer among Chinese women in shanghai

目的:探讨乳腺癌组织中磷脂酰肌醇-3-激酶催化亚单位α(PIK3CA)基因2个热点突变区域第9和第20外显子的突变,以及该突变与乳腺癌临床病理特征之间的关系。方法:45例乳腺癌标本提取DNA后,对第9及第20外显子进行PCR扩增,产物纯化后测序。另取10例乳腺良性肿瘤组织标本作为对照。结果:在45例乳腺癌组织标本中共发现14例(31%)PIK3CA基因突变,其中第9外显子8例(57%),第20外显子6例(43%)。在第9外显子突变中,1例为C1616G(P539R),1例为G1633A(E545K),6例为A1634C(E545A)。第20外显子的6例突变均为A3140G(H1047R)。10例良性肿瘤对照中均未发现突变。第9与第20外显子突变在浸润性导管癌和浸润性小叶癌中的分布差异无统计学意义,P>0.05。PIK3CA基因突变与患者年龄、肿瘤大小、淋巴结状态、ER/PR状态、HER-2表达和p53表达之间无明显相关性,P>0.05。结论:PIK3CA基因可能与乳腺癌的发生、发展及预后相关。但PIK3CA基因突变与乳腺癌临床病理特征之间无明显相关性。

OBJECTIVE：To investigate the two mutational hotspots in exon 9 and exon 20 of PIK3CA gene in breast cancer,and the association of the mutation with the pathological features of breast cancer. METHODS： PCR amplification of exons 9 and 20 was done after extracting DNA from 45 samples of breast cancer,followed by sequence after the product was purified. Another 10 samples of benign breast tumor were chosen as controls. RESULTS： 14（31%） missense mutations,8（57%） in exon 9,6（43%） in exon 20 were found. In eight cases of exon 9,1 was C1616G （P539R）,1 was G1633A （E545K）,and 6 were A1634C （E545A）. All the 6 cases of mutations in exon 20 were A3140G （H1047R）. No mutation was found in 10 cases of benign breast tumor. There was no significant difference in the distribution of mutation between invasive ductal carcinoma and invasive lobular carcinoma in both exon 9 and exon 20（P〉0.05）. The mutation of PIK3CA gene had no significant correlation with the age,tumor size,lymph node status,ER/PR status,HER-2 expression,and p53 expression（P〉0.05）. CONCLUSIONS： PIK3CA gene may be associated with the development and prognosis of breast cancer. However,there is no significant correlation between PIK3CA gene mutation and the pathological features of breast cancer.