We aimed to assess whether the breast-cancer intermediate-risk genes CHEK2, ATM ant TP53 were subject to differential allelic expression (DAE) in lymphoblastoid cell lines (LCLs) from high-risk breast cancer patients for whom no mutation in BRCA1 or BRCA2 had been identified.We implemented an assay based on high-resolution melting curve analysis (HRM) of single labeled fluorescent probes to detect allelic expression imbalance. The method relies on the distinction of the two alleles of an exonic marker SNP in heterozygous individuals with a fluorescent signal correlated to the relative abundance of each transcript. We developed an analysis tool for HRM data processing, specifically dedicated to DAE assessment. In our series, we found evidence for DAE for CHEK2, in carriers of the truncating mutation 1100delC. When combining mutation-screening data and assessment of DAE, we did not identify functional regulatory variant located in cis of the studied genes that would lead to DAE, in the transcriptional regulatory milieu of freely proliferating LCLs. Our results support that HRM is a method with high sensitivity and accuracy that can be used for DAE assessment. This approach can be applied to study breast and blood tissue samples. The latter would be of great interest for high-throughput mutation screening projects aiming to identify dysfunctional regulatory variants in candidate genes.
