乳腺癌是女性常见的患癌类型。通过连锁分析和候选基因筛查已经鉴定出诸多乳腺癌易感基因。但是仍有超过50％的乳腺癌未能鉴定出易感基因的突变。在本研究中我们对1例中国乳腺癌家系中患者进行外显子组测序。同时收集了13例非BRCA1／BRCA2突变乳腺癌家系和78例韩国散发乳腺癌外显子测序数据进行重分析。首先，我们从乳腺癌家系和散发样本中鉴定出了已知乳腺癌致病性突变，累及的基因包括BRCA1，BRCA2，CHEK2，NBN等。其次，我们也鉴定出新的候选基因如MRE11A，RECQL，NCK1。基于非负矩阵因子化方法，我们从散发乳腺癌体细胞突变中鉴定出多个突变特征，包括APOBEC-相关突变特征以及错配修复缺陷相关突变特征。通过微卫星不稳定性分析，我们确定了错配修复缺陷真实存在于乳腺癌患者中。因此乳腺癌具有很强的遗传异质性，外显子组测序的灵敏性足以鉴定出潜在的致病基因。通过体外过表达实验，我们确认了突变NCK1／p.D73H可以促进MCF7细胞的增殖和侵袭。生存分析结果显示，NCK1表达与乳腺癌转移和复发风险相关。乳腺癌属于高度异质性疾病，因此可能存在很多其他潜在的乳腺癌易感基因。 蓝色橡皮疱痣综合征(Blue rubber bleb nevus syndrome，BRBNS)属于静脉畸形综合征，主要出现于皮肤和胃肠道，伴随肠道出血症状，患者一般为幼儿。已知基因TEK／TIE2的突变可导致家族遗传型静脉畸形和散发静脉畸形。最近研究发现，基因TEK体细胞突变可以导致蓝色橡皮疱痣综合征。除此之外，基因PIK3CA的体细胞突变对静脉畸形的发生也有贡献。说明静脉畸形及其综合征具有高度遗传异质性。通过外显子组测序，我们从一例散发静脉畸形患者中鉴定出基因TEK(p.L914F)突变。从两例蓝色橡皮疱痣综合征患者中鉴定到基因GLMN突变(p.P254R和p.E544X)。体外过表达实验显示，稳定表达GLMN突变体的人脐静脉细胞与稳定表达GLMN野生型的人脐静脉细胞相比mTOR通路被激活。并且，两例未能检测出基因GLMN或TEK突变的蓝色橡皮疱痣综合征接受雷帕霉素治疗后症状得到缓解。因此mTOR信号通路的异常可能是蓝色橡皮疱痣综合征病变的原因。 关键词 外显子组测序，乳腺癌，NCK1，蓝色橡皮疱痣综合征，GLMN，mTOR

 Breast cancer is prevalent among female worldwide. Multiple breast cancer predisposition genes have been identified via linkage or candidate gene screening. However, the predisposition genes of more than 50% breast cancer patients are still undetermined. In this study, we applied whole exome sequencing to all patients of one Chinese breast cancer pedigree; meanwhile, we collected whole exome sequencing data about 13 non-BRCA1/2 breast cancer pedigrees and 78 sporadic Korean breast cancer patients. In our analysis, we identified certain known pathogenic variants from both familial and sporadic breast cancer patients. Secondly, we identified novel predisposition ones, which impaired gene MRE11A, RECQL and NCK1. Finally, we deciphered four mutational signatures, including APOBEC-related and mismatch repair deficiency-related signatures, from the sporadic breast cancer cohort. To confirm the roles of the novel predisposition genes, we focused on gene NCK1. In vitro, NCK1 (p.D73H) could promote viability and invasion of breast cancer cell line MCF7. Expression of NCK1 was correlated with risk of breast cancer metastasis and relapse. Our results confirm that breast cancer is highly heterogenous, more predisposition genes will be identified with sample size increasing. Blue rubber bleb nevus syndrome (BRBNS), which is a rare venous malformation associated disorder and mostly affects skin and gastrointestinal tract in early childhood. Both familial and sporadic VM can be explained by mutations in TEK/TIE2. Recently, some somatic mutations in TEK have also been identified from cases of BRBNS. In addition, somatic mutations in PIK3CA have also been determined to be disease-causing in sporadic VM. Therefore, the underlying genetic factors contributing to pathogenesis of VM and associated sysdrome could have high heterogeneity. Through whole-exome sequencing, we identified one somatic mutation in the TEK gene (p.L914F) from one case of sporadic VM and two rare germline GLMN variants, GLMN (p.P254R) and GLMN (p.E544X), from two separate cases of BRBNS. HUVECs transfected with GLMN mutants exhibited increased mTOR signaling compared with that of cells expressing the wild-type protein. In addition, in some cases of TEK-mutation-negative and GLMV-mutation-negative BRBNS, symptoms were relieved after rapamycin treatment. Therefore, abnormal mTOR signaling might be a major cause of BRBNS. Keywords: whole exome sequencing, breast cancer, NCK1, blue rubber bleb nevus syndrome, GLMN, mTOR