[Chromosomal translocation involving USP6 gene in nodular fasciitis].

Objective: To investigate the frequency of USP6 gene rearrangement in nodular fasciitis (NF) and to evaluate its clinical application.
Methods: Twenty nine cases of previously diagnosed NF were screened for the presence of the USP6 gene rearrangement by interphase fluorescence-in-situ hybridization (FISH) on formalin-fixed paraffin-embedded tissue. Fifteen of these cases, which had available tissue, were also analysed for MYH9-USP6 fusion transcripts by reverse transcription-polymerase chain reaction (RT-PCR).
Results: Twenty four of the 29 cases (83%) were positive for the USP6 gene rearrangement by interphase FISH. The 15 cases with RT-PCR showed the following results: 11 positive, one deletion and three negative for USP6 gene rearrangement. Of these 15 cases, eight (8/15) showed MYH9-USP6 fusion transcript by RT-PCR. Of these eight cases, seven were positive for USP6 gene rearrangement and one showed USP6 deletion by FISH.
Conclusions: USP6 gene rearrangement is a recurrent genetic event in NF. It is a valuable ancillary tool for the pathological diagnosis of these lesions.