ABSTRACT
PURPOSE: Large genomic rearrangements (LGRs) constitute a significant share of pathogenic BRCA1 mutations. Multiplex ligation-dependent probe amplification (MLPA) is a leading method for LGR detection; however, it is entirely based on the use of commercial kits, includes relatively time-consuming hybridization step, and is not convenient for large-scale screening of recurrent LGRs. MATERIALS AND METHODS: We developed and validated the droplet digital PCR (ddPCR) assay, which covers the entire coding region of BRCA1 gene and is capable to precisely quantitate the copy number for each exon. RESULTS: 141 breast cancer (BC) patients, who demonstrated evident clinical features of hereditary BC but turned out to be negative for founder BRCA1/2 mutations, were subjected to the LGR analysis. Four patients with LGR were identified, with three cases of exon 8 deletion and one women carrying the deletion of exons 5-7. Excellent concordance with MLPA test was observed. Exon 8 copy number was tested in additional 720 BC and 184 ovarian cancer (OC) high-risk patients, and another four cases with the deletion were revealed; MLPA re-analysis demonstrated that exon 8 loss was a part of a larger genetic alteration in two cases, while the remaining two patients had isolated defect of exon 8. Long-range PCR and next generation sequencing of DNA samples carrying exon 8 deletion revealed two types of recurrent LGRs. CONCLUSION: Droplet digital PCR is a reliable tool for the detection of large genomic rearrangements.
Subject(s)
Breast Neoplasms/genetics , Gene Rearrangement , Genes, BRCA1 , Genetic Testing , Polymerase Chain Reaction , Breast Neoplasms/diagnosis , Exons , Female , High-Throughput Nucleotide Sequencing , Humans , Nucleic Acid Amplification Techniques , Polymerase Chain Reaction/methods , Reproducibility of Results , Sequence DeletionABSTRACT
Breast carcinomas caused by inheritance of cancer-predisposing germ-line mutations have specific bioclinical features. This study aimed to analyze the efficacy of conventional cytotoxic treatment in BRCA1 and CHEK2 mutation carriers and non-carriers. The study included 415 Russian breast cancer patients aged 50 years or younger, who were subjected to various standard schemes of neoadjuvant therapy. The choice of therapy was done without the knowledge of the mutations status, because DNA testing was performed retrospectively using the archival tissue samples. 19 BRCA1 (4.6%) and 8 CHEK2 (1.9%) heterozygous genotypes were identified. BRCA1 mutation carriers achieved pathological complete response more frequently than non-carriers [6/19 (31.6%) vs. 46/388 (11.9%), p = 0.024]; this effect was limited to women treated by anthracycline-based therapy without taxanes [5/9 (55.6%) vs. 28/247 (11.3%), p = 0.002] and was not observed in any of 7 BRCA1 carriers receiving taxane-containing regimens. CHEK2 heterozygotes did not experience pathological complete response and showed lower frequency of objective clinical responses as compared to mutation non-carriers [4/8 (50%) vs. 333/388 (85.5%), p = 0.020]; the efficacy of neoadjuvant therapy was particularly poor in CHEK2 carriers receiving anthracyclines without taxanes. This study provides evidence for distinct sensitivity of BRCA1 and CHEK2 mutation-driven breast carcinomas to standard chemotherapeutic schemes.
Subject(s)
BRCA1 Protein/genetics , Breast Neoplasms/genetics , Checkpoint Kinase 2/genetics , Neoadjuvant Therapy , Adult , Anthracyclines/administration & dosage , Breast Neoplasms/drug therapy , Breast Neoplasms/pathology , Female , Genetic Predisposition to Disease , Germ-Line Mutation , Heterozygote , Humans , Middle Aged , Taxoids/administration & dosageABSTRACT
We describe two unrelated patients aged 9 and 12 years. The first patient presented with multiple congenital contractures not associated with webbing (pterygia). Interestingly, his genetic testing showed the typical genotypic criteria of Escobar syndrome (CHRNG heterozygous mutation). The characteristics of the second child were compatible with the phenotypic and genotypic criteria for Escobar syndrome. Both patients manifested the typical facial features suggestive of Escobar syndrome. The aim of this paper is twofold: first, to illustrate that the absence of popliteal webbing is not a sufficient reason to exclude Escobar syndrome in patients with multiple contractures and second, dysmorphic facial features and the presence of certain radiological abnormalities might be considered baseline diagnostic tools in favor of this syndromic entity.
