Polymerase chain reaction‐denaturing gradient gel electrophoresis (PCR/DGGE)‐based detection of clonal T‐cell receptor γ gene rearrangements in paraffin‐embedded cutaneous biopsies in cutaneous T‐cell lymphoproliferative diseases*

Polymerase chain reaction (PCR)-based amplification of T-cell receptor (TCR)-gamma genes is a novel technique that can detect a clone of T cells comprising less than 1% of the total T cells in a lymphoid infiltrate. Besides greater sensitivity than Southern blotting, this technique can be performed with smaller quantities of lower molecular weight genomic DNA as template. We retrospectively analyzed 12 paraffin-embedded biopsies of cutaneous T-cell lymphoma (CTCL), 1 case suspicious for CTCL, 1 case of granulomatous slack skin, and 8 cases of inflammatory skin diseases to determine if PCR-denaturing gradient gel electrophoresis (PCR-DGGE) analysis can detect TCR-gamma gene rearrangements on paraffin-embedded specimens. We were able to amplify Vgamma1-8 TCR sequences in each case and detected a dominant clone in 9 of 12 cases of CTCL and in granulomatous slack skin. We analyzed Vgamma9 sequences in 9 cases of CTCL and detected a dominant clone in 4 cases. This study demonstrates that PCR-DGGE can easily be applied retrospectively to cutaneous biopsies of lymphoproliferative diseases when fresh tissue is not available.