Identification of BRCA1 and BRCA2 carriers by allele-specific gene expression (AGE) analysis.
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.
Montagna
Marco
M
Department of Oncology and Surgical Sciences, Oncology Section, University of Padova, Padova, Italy.
Agata
Simona
S
De Nicolo
Arcangela
A
Menin
Chiara
C
Sordi
Gianni
G
Chieco-Bianchi
Luigi
L
D'Andrea
Emma
E
D000483:Alleles; D001943:Breast Neoplasms / Q000453:epidemiology / Q000235:genetics*; D017931:DNA Primers / Q000737:chemistry; D004273:DNA, Neoplasm / Q000032:analysis; D005091:Exons / Q000235:genetics; D005260:Female; D015870:Gene Expression / Q000235:genetics*; D019398:Genes, BRCA1; D024522:Genes, BRCA2; D006580:Genetic Carrier Screening / Q000379:methods; D005820:Genetic Testing / Q000379:methods; D006579:Heterozygote; D006801:Humans; D010051:Ovarian Neoplasms / Q000453:epidemiology / Q000235:genetics*; D018807:Polymorphism, Single-Stranded Conformational; D012334:RNA, Neoplasm / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction
D017931:DNA Primers; D004273:DNA, Neoplasm; D012334:RNA, Neoplasm