Affiliation:
1. Section for Cancer Cytogenetics Institute for Cancer Genetics and Informatics, The Norwegian Radium Hospital, Oslo University Hospital Oslo Norway
2. Department of Pathology The Norwegian Radium Hospital, Oslo University Hospital Oslo Norway
Abstract
ABSTRACTBackgroundCellular angiofibroma, a rare benign mesenchymal neoplasm, is classified within the 13q/RB1 family of tumors due to morphological, immunohistochemical, and genetic similarities with spindle cell lipoma. Here, genetic data reveal pathogenetic heterogeneity in cellular angiofibroma.MethodsThree cellular angiofibromas were studied using G‐banding/Karyotyping, array comparative genomic hybridization, RNA sequencing, and direct cycling sequencing.ResultsThe first tumor carried a del(13)(q12) together with heterozygous loss and minimal expression of the RB1 gene. Tumors two and three displayed chromosome 8 abnormalities associated with chimeras of the pleomorphic adenoma gene 1 (PLAG1). In tumor 2, the cathepsin B (CTSB) fused to PLAG1 (CTSB::PLAG1) while in tumor 3, the mir‐99a‐let‐7c cluster host gene (MIR99AHG) fused to PLAG1 (MIR99AHG::PLAG1), both leading to elevated expression of PLAG1 and insulin growth factor 2.ConclusionThis study uncovers two genetic pathways contributing to the pathogenetic heterogeneity within cellular angiofibromas. The first aligns with the 13q/RB1 family of tumors and the second involves PLAG1‐chimeras. These findings highlight the diverse genetic landscape of cellular angiofibromas, providing insights into potential diagnostic strategies.