ABSTRACT
AIMS: Spindle-cell/sclerosing rhabdomyosarcomas (SS-RMS) are clinically and genetically heterogeneous. They include three well-defined molecular subtypes, of which those with EWSR1/FUS::TFCP2 rearrangements were described only recently. This study aimed to evaluate five new cases of SS-RMS and to perform a clinicopathological and statistical analysis of all TFCP2-rearranged SS-RMS described in the English literature to more comprehensively characterize this rare tumour type. METHODS AND RESULTS: Cases were retrospectively selected and studied by immunohistochemistry, fluorescence in situ hybridization with EWSR1/FUS and TFCP2 break-apart probes, next-generation sequencing (Archer FusionPlex Sarcoma kit and TruSight RNA Pan-Cancer Panel). The PubMed database was searched for relevant peer-reviewed English reports. Five cases of SS-RMS were found. Three cases were TFCP2 rearranged SS-RMS, having FUSex6::TFCP2ex2 gene fusion in two cases and triple gene fusion EWSR1ex5::TFCP2ex2, VAX2ex2::ALKex2 and VAX2intron2::ALKex2 in one case. Two cases showed rhabdomyoblastic differentiation and spindle-round cell/sclerosing morphology, but were characterized by novel genetic fusions including EWSR1ex8::ZBTB41ex7 and PLOD2ex8::RBM6ex7, respectively. In the statistical analysis of all published cases, CDKN2A or ALK alterations, the use of standard chemotherapy and age at presentation in the range of 18-24 years were negatively correlated to overall survival. CONCLUSION: EWSR1/FUS::TFCP2-rearranged SS-RMS is a rare rhabdomyosarcoma subtype, affecting predominantly young adults with average age at presentation 34 years (median 29.5 years; age range 7-86 years), with a predilection for craniofacial bones, rapid clinical course with frequent bone and lung metastases, and poor prognosis (3-year overall survival rate 28%).
Subject(s)
Rhabdomyosarcoma , Transcription Factors , Young Adult , Child , Humans , Adult , Adolescent , Middle Aged , Aged , Aged, 80 and over , In Situ Hybridization, Fluorescence , Retrospective Studies , Transcription Factors/genetics , RNA-Binding Protein EWS/genetics , Rhabdomyosarcoma/genetics , Rhabdomyosarcoma/pathology , Gene Fusion , Biomarkers, Tumor/genetics , RNA-Binding Proteins/genetics , Procollagen-Lysine, 2-Oxoglutarate 5-Dioxygenase/genetics , DNA-Binding Proteins/geneticsABSTRACT
AIMS: Primary renal well-differentiated neuroendocrine tumour (NET) (hereafter referred to as renal NET) is rare, with ~100 cases having been reported in the literature. There are also limited data on the molecular-genetic background of primary renal NETs. METHODS AND RESULTS: We analysed 11 renal NETs by using next-generation sequencing (NGS) to identify characteristic genetic aberrations. All tumours were positive for synaptophysin, and also expressed insulinoma-associated protein 1 (10/11), chromogranin-A (8/11), and CD56 (3/11). Cytoplasmic positivity of CD99 was present in eight of 11 cases, and strong nuclear expression of α-thalassaemia/mental retardation syndrome X-linked (ATRX) was retained in all 11 cases. Molecular-genetic analysis of aberration of VHL gave negative results in all cases. Loss of heterozygosity on chromosome 3p21 was found in three of nine analysable cases. NGS was successful in nine cases, showing a total of 56 variants being left after the updated filtering process, representing an average of five variants per sample. All analysable cases were negative for ATRX and DAXX (death-domain associated protein X) mutations. The most frequently mutated genes were CDH1 and TET2, with three mutations in two cases. Mutations in AKT3, ROS1, PIK3R2, BCR and MYC were found in two cases. The remaining 41 genes were found to be mutated only in individual cases. In four cases, the mutations affected a subset of genes related to angiogenesis. CONCLUSIONS: Overall, the mutation profile of primary renal NETs is variable, and none of the studied genes or affected pathways seems to be specific for renal NET.
