Montagna Marco, Dalla Palma Maurizia, Menin Chiara, Agata Simona, De Nicolo Arcangela, Chieco-Bianchi Luigi, D'Andrea Emma
IST-Genova c/o, Azienda Ospedaliera, Padua, Italy.
Hum Mol Genet. 2003 May 1;12(9):1055-61. doi: 10.1093/hmg/ddg120.
The recent identification of major genomic rearrangements in breast and breast/ovarian cancer families has widened the mutational spectrum of the BRCA1 gene, thus increasing the number of informative patients who can benefit from molecular screening. Numerous types of alterations have been identified in different populations with variable frequencies, probably due to both ethnic diversity and the technical approach employed. In fact, although several methods have been successfully used to detect large genomic deletions and insertions, most are laborious, time-consuming, and of variable sensitivity. In order to estimate the contribution of BRCA1 genomic rearrangements to breast/ovarian cancer predisposition in Italian families, we applied, for the first time as a diagnostic tool, the recently described multiplex ligation-dependent probe amplification (MLPA) methodology. Among the 37 hereditary breast/ovarian cancer (HBOC) families selected, all had a high prior probability of BRCA1 mutation, and 15 were previously shown to carry a mutation in either the BRCA2 (five families) or BRCA1 gene (10 families, including one genomic rearrangement). The application of BRCA1-MLPA to the remaining 22 uninformative families allowed the identification of five additional genomic rearrangements. Moreover, we observed that loss of constitutive heterozygosity of polymorphic markers in linkage disequilibrium is predictive of such BRCA1 alterations. By means of this approach, we demonstrate that BRCA1 genomic deletions account for more than one-third (6/15) of the pathogenic BRCA1 mutations in our series. We therefore propose to systematically include MLPA in the BRCA1 mutational analysis of breast/ovarian cancer families.
近期在乳腺癌和乳腺癌/卵巢癌家族中发现的主要基因组重排拓宽了BRCA1基因的突变谱,从而增加了可从分子筛查中受益的信息丰富患者的数量。在不同人群中已鉴定出多种类型的改变,频率各异,这可能是由于种族多样性和所采用的技术方法所致。事实上,尽管已成功使用多种方法检测大的基因组缺失和插入,但大多数方法费力、耗时且灵敏度不一。为了评估BRCA1基因组重排在意大利家族乳腺癌/卵巢癌易感性中的作用,我们首次将最近描述的多重连接依赖探针扩增(MLPA)方法作为诊断工具应用。在所选择的37个遗传性乳腺癌/卵巢癌(HBOC)家族中,所有家族先前都有较高的BRCA1突变概率,其中15个家族先前已被证明携带BRCA2(5个家族)或BRCA1基因(10个家族,包括1个基因组重排)的突变。将BRCA1-MLPA应用于其余22个信息不明确的家族,又鉴定出另外5个基因组重排。此外,我们观察到连锁不平衡中多态性标记的组成型杂合性缺失可预测此类BRCA1改变。通过这种方法,我们证明在我们的系列中,BRCA1基因组缺失占致病性BRCA1突变的三分之一以上(6/15)。因此,我们建议在乳腺癌/卵巢癌家族的BRCA1突变分析中系统地纳入MLPA。