Δ-PCR, A Simple Method to Detect Translocations and Insertion/Deletion Mutations

Area of Science:

• Molecular Biology
• Genetics
• Oncology

Background:

• Detecting chromosomal translocations and small mutations is difficult due to variable amplicon sizes, multiple breakpoints, and low signal.
• Specific challenges exist for BCL2-IGH translocations in follicular lymphoma and FLT3 internal tandem duplications in leukemia.

Purpose of the Study:

• To develop a sensitive and specific PCR strategy for identifying genetic rearrangements and mutations with variable breakpoints.
• To validate the efficacy of the new method for diagnosing follicular lymphoma and leukemia.

Main Methods:

• Developed Δ-PCR, a multiplex PCR strategy using two forward primers (external and internal) and one reverse primer.
• The internal primer acts as a probe, defining a specific distance Δ from the external primer.
• Applied to detect BCL2-IGH translocations in follicular lymphoma and FLT3 mutations in leukemia using formalin-fixed, paraffin-embedded samples.

Main Results:

• Δ-PCR successfully identified specific breakpoints in BCL2-IGH translocations with high sensitivity, even with low signal and high background noise.
• The method confirmed the validity of rearrangements and breakpoint identity through unique amplicon size differences.
• Demonstrated effectiveness in detecting minor leukemic clones with internal tandem duplication mutations.

Conclusions:

• Multiplex Δ-PCR is a simple, sensitive, and robust strategy for identifying translocations with multiple breakpoints or partners.
• The Δ-PCR method shows broad applicability for detecting various insertion/deletion and duplication mutations in molecular diagnostics.