Increased sensitivity of B-cell clonality analysis in formalin-fixed and paraffin-embedded B-cell lymphoma samples using an enzyme blend with both 5'-->3' DNA polymerase and 3'-->5' exonuclease activity.

Polymerase chain reaction (PCR)-based detection of immunoglobulin heavy chain (IgH) gene rearrangement for determination of B-cell clonality needs to be simple but optimally sensitive. Efficient IgH PCR analysis can be hampered by sequence variability in the template DNA, despite of the use of degenerative primers. To improve sensitivity of the B-cell clonality analysis in formalin-fixed and paraffin-embedded (FFPE) tissues, we have performed framework three-area (FR3)/joining gene (JH) IgH PCR utilizing an enzyme blend (r Tth DNA Polymerase, XL) providing both 5'-->3' polymerase and 3'-->5' exonuclease activities.