Montagna Marco, Agata Simona, De Nicolo Arcangela, Menin Chiara, Sordi Gianni, Chieco-Bianchi Luigi, D'Andrea Emma
Department of Oncology and Surgical Sciences, Oncology Section, University of Padova, Padova, Italy.
Int J Cancer. 2002 Apr 10;98(5):732-6. doi: 10.1002/ijc.10273.
Mutations in BRCA1 and BRCA2 genes confer a high risk of breast and ovarian cancer. As such, their identification is essential to reduce the risk of disease in healthy carriers, as well as in carriers who have already developed the disease because they are at increased risk for a second malignancy; moreover, noncarriers of BRCA1 and BRCA2 mutated families can be spared anxiety and unnecessary medical interventions. A number of problems, including large gene size, complex mutational spectra and genetic heterogeneity of the disease, however, make genetic testing labor intensive and often inconclusive. We devised a new mutation detection strategy called AGE (allele-specific gene expression) analysis that relies on the detection of a "functional effect" of the mutation at the RNA level known as "nonsense-mediated RNA decay," thus avoiding several of the problems of BRCA1 and BRCA2 genetic testing. In particular, (i) AGE analysis discriminates among the predisposing genes and identifies mutation carriers with a single RT-PCR reaction; (ii) it relies on the effect of truncating mutations, which represent the large majority of cases and thus identifies mutation carriers regardless of the specific genomic alteration; and (iii) it is specific for cis-regulatory mutations that are missed at present by most of the methods. As AGE analysis has the potential to identify most of the BRCA1 and BRCA2 mutation carriers, it can be used as a preliminary screening method, thereby accelerating and increasing the sensitivity of the genetic testing process. Notably, other hereditary diseases whose genetic analysis is hampered by similar problems could benefit from this kind of approach.
BRCA1和BRCA2基因的突变会导致患乳腺癌和卵巢癌的高风险。因此，对它们的识别对于降低健康携带者以及已经患病的携带者患第二种恶性肿瘤的风险至关重要；此外，BRCA1和BRCA2突变家族的非携带者可以避免焦虑和不必要的医疗干预。然而，包括基因规模大、突变谱复杂以及疾病的遗传异质性等一系列问题，使得基因检测工作强度大且往往没有定论。我们设计了一种新的突变检测策略，称为AGE（等位基因特异性基因表达）分析，该策略依赖于在RNA水平检测被称为“无义介导的RNA降解”的突变“功能效应”，从而避免了BRCA1和BRCA2基因检测中的几个问题。具体而言，（i）AGE分析能够区分易感基因，并通过一次逆转录聚合酶链反应（RT-PCR）鉴定突变携带者；（ii）它依赖于截短突变的效应，而截短突变占大多数病例，因此无论具体的基因组改变如何都能鉴定突变携带者；（iii）它对目前大多数方法遗漏的顺式调控突变具有特异性。由于AGE分析有可能识别大多数BRCA1和BRCA2突变携带者，它可以用作初步筛查方法，从而加快并提高基因检测过程的灵敏度。值得注意的是，其他遗传分析因类似问题而受阻的遗传性疾病也可能从这种方法中受益。
