Amplification and thrifty single-molecule sequencing of recurrent somatic structural variations

Area of Science:

• Genomics
• Cancer Biology
• Molecular Diagnostics

Background:

• Genomic rearrangements and tumor-suppressor gene deletions are common in various cancers.
• Identifying precise structural variant (SV) breakpoints is crucial for patient-specific tumor biomarker development.
• Existing sequencing methods may require validation for SV detection.

Purpose of the Study:

• To introduce AmBre (Amplification of Breakpoints), a new method for targeting and characterizing SV breakpoints.
• To validate SVs identified by whole-exome/genome sequencing and hybridization arrays.
• To enable the detection of SV breakpoints in heterogeneous tumor and germline DNA samples.

Main Methods:

• AmBre utilizes a PCR-based approach with carefully designed primers to amplify DNA segments containing SV breakpoints.
• Simultaneous long-read sequencing of amplified breakpoints is performed using Pacific Biosciences technology.
• A specialized algorithm separates sequencing reads to identify and confirm consensus breakpoint sequences.

Main Results:

• AmBre successfully identified CDKN2A deletion breakpoints in multiple cancer cell lines (A549, CEM, Detroit562, MOLT4, MCF7, T98G).
• The method accurately detected both breakpoints of the RUNX1-RUNX1T1 reciprocal translocation in the Kasumi-1 cell line.
• AmBre demonstrated high sensitivity, successfully targeting SVs present at a 1:1000 mixture of DNA.

Conclusions:

• AmBre is an effective method for precise SV breakpoint characterization in cancer research.
• The technique offers a robust approach for validating SVs and discovering novel breakpoints.
• AmBre has potential applications in developing personalized cancer diagnostics and therapeutics.