Anchored Multiplex PCR for Targeted Next-Generation Sequencing Reveals Recurrent and Novel USP6 Fusions and Upregulation of USP6 Expression in Aneurysmal Bone Cyst
GENES CHROMOSOMES & CANCER
Authors: Guseva, Natalya V.; Jaber, Omar; Tanas, Munir R.; Stence, Aaron A.; Sompallae, Ramakrishna; Schade, Jenna; Fillman, Allison N.; Miller, Benjamin J.; Bossler, Aaron D.; Ma, Deqin
Abstract
Primary aneurysmal bone cyst (ABC) is a neoplastic process due to recurrent translocations involving the USP6 gene. By fluorescence in situ hybridization, up to 69% of primary ABCs harbored USP6 translocations; no USP6 translocation was found in secondary ABC or giant cell tumor of bone (GCT). GCT can recur locally, metastasize to the lungs in some cases, and rarely undergo malignant transformation. Differentiating primary ABC from its mimics is important for treatment and prognosis. We evaluated USP6 fusion and expression in 13 cases of primary and 1 case of secondary ABC, and 9 cases of GCT using nucleic acid extracted from formalin-fixed, paraffin-embedded tissue and a next generation sequencing (NGS)-based assay. USP6 fusions including 7 novel fusions and USP6 transcripts were identified in all 13 primary ABCs. Nine cases with strong evidence of fusions showed high levels of USP6 transcripts by reverse transcription-PCR (RT-PCR). The remaining four had no detectable USP6 expression by a first-round of RT-PCR but the presence of USP6 transcripts was identified by a second-round, nested PCR. The major fusions were confirmed by RT-PCR followed by Sanger sequencing. No USP6 fusion or transcript was detected in any of the GCTs or the case of secondary ABC by NGS or by two rounds of PCR. All USP6 translocations resulted in fusion of the entire USP6 coding sequence with promoters of the fusion gene leading to upregulation of USP6 transcription, which is likely the underlying mechanism for ABC oncogenesis. (C) 2016 Wiley Periodicals, Inc.
Cutaneous nodular fasciitis with genetic analysis: a case series
JOURNAL OF CUTANEOUS PATHOLOGY
Authors: Kumar, Erica; Patel, Nimesh R.; Demicco, Elizabeth G.; Bovee, Judith V. M. G.; Olivera, Andre M.; Lopez-Terrada, Dolores H.; Billings, Steven D.; Lazar, Alexander J.; Wang, Wei-Lien
Abstract
Nodular fasciitis is a benign self-limited myofibroblastic neoplasm, which usually involves the upper extremities and trunk of young patients. These tumors have been shown to harbor a translocation involving the MYH9 and USP6 genes, leading to overexpression of the latter. We report seven cases of nodular fasciitis with cutaneous presentations. All cases involved the dermis, with six involving the superficial subcutis, and one auricular tumor extending into cartilage. All cases showed USP6 rearrangement by fluorescence in situ hybridization; in two of three cases, the characteristic MYH9-USP6 fusion was shown by RT-PCR. All patients underwent conservative resection. Nodular fasciitis is an uncommon mesenchymal neoplasm that can occasionally present in superficial locations and is sometimes mistaken for a malignant process. Molecular testing can be useful to distinguish this entity from other cutaneous spindle cell tumors.