The significance of multiplex PCR/heteroduplex analysis-based TCR-γ gene rearrangement combined with laser-capture microdissection in the diagnosis of early mycosis fungoides

Abstract

The diagnosis of early mycosis fungoides (MF) is a big challenge to dermatologists and dermatopathologists because it lacks specific clinicopathologic features. Fifty-two paraffin-embedded skin samples from 50 patients, including 31 with suspected MF, 10 with typical MF and 9 with benign inflammatory dermatosis (BID), were obtained from our archives. DNA was extracted both by traditional phenol-chloroform method and by the laser-capture microdissection (LCM)-proteinase K approach. The T(VG) /T(JG) , V(2-5) /V(8-12) /JGT(1) and BIOMED-2-TCR-γ primers were used to assess TCR-γ monoclonal rearrangement as measured by polymerase chain reaction (PCR). In the suspected MF group, clonal TCR-γ gene rearrangements were detected in 11/31 cases (35.5%) by phenol-chloroform DNA extraction and in 25/31 cases (80.7%) by LCM-proteinase K extraction (p < 0.05). While T-cell clonality was detected in 8/10 cases (80%) by the phenol-chloroform method and 10/10 cases (100%) by LCM (p > 0.05) in the typical MF group, no TCR-γ monoclonal rearrangement was detected in the BID group. The strategy of multiple PCR/heteroduplex analysis for TCR-γ gene rearrangement combined with LCM increases the detection rate of clonal TCR-γ gene rearrangement in early MF cases and could provide strong evidence to confirm the diagnosis of early MF.