74例早发性乳腺癌患者BRCA1和BRCA2基因致病突变研究

目的 研究乳腺癌易感基因BRCA1和BRCA2在早发性乳腺癌(确诊年龄≤35岁)患者中突变情况,分析致病突变与临床特征之间关系.方法 选择2014年9月至2016年6月期间就诊于军事医学科学院附属医院的早发性乳腺癌患者74例,采用高通量二代测序技术以及生物信息分析,对纳入患者BRCA1和BRCA2基因的49个外显子序列及拼接区序列进行检测分析,并将患者按临床特征分组,χ2检验比较BRCA1和BRCA2致病突变在各组的分布.结果 在74例早发性乳腺癌患者中,检测到15例(20.27%)BRCA1/2致病突变,包括5例(6.76%)BRCA1致病突变,10例(13.51%)BRCA2致病突变.其中11例为新发现致病突变,检测到1例患者携带相对高频致病基因突变BRCA1:c.5470_5477delTGCCCAAT.有乳腺癌或卵巢癌家族史组携带致病突变率明显高于无家族史组(40.91% vs 11.54%,χ2=6.534,P=0.011).结论 BRCA1/2致病突变对早发性乳腺癌意义重大,尤其是伴有乳腺癌或卵巢癌家族史的早发性乳腺癌.新发现的致病突变可能为中国人群特有突变.BRCA1:c.5470_5477delTGCCCAAT可能成为中国人群的始祖突变.

BRCA1 and BRCA2 pathogenic mutations in 74 patients with early-onset breast cancer

Objective To investigate the pathogenic mutations of BRCA1 and BRCA2 in patients with early-onset breast cancer(≤35 years) and explore the relationships between BRCA1/2 mutations and clinical features.Methods Seventy-four patients with early-onset breast cancer were enrolled,who were treated in Hospital 307 between September 2014 and June 2016.High-throughput sequencing was used to test the 49 exon sequences and adjacent sequences of BRCA1 and BRCA2.χ2 test was used to analyze the distribution of BRCA1/2 pathogenic mutations in each group that was set up according to clinical features.Results Fifteen mutations(20.27%) were identified,including 5(6.76%) in BRCA1 and 10(13.51%) in BRCA2.Eleven new pathogenic mutations were discovered,and BRCA1:c.5470_5477delTGCCCAAT was found in one patient.The frequency of BRCA1/2 mutations in the group with a family history of breast cancer or ovarian cancer was higher than in the group without a family history (40.91% vs 11.54%) (χ2=6.534,P=0.011).Conclusion BRCA1/2 pathogenic mutation is significant for early-onset breast cancer,especially for those with a family history of breast or ovarian cancer.The new mutations may be specific to Chinese people.BRCA1:c.5470_5477delTGCCCAAT may be the ancestor mutation among the Chinese.