Publication Date:
2019-11-13
Description:
Introduction: Histiocytic and dendritic neoplasms are a diverse group of uncommon hematologic tumors arising from monocytic or dendritic cell lineage. While genomic profiles for the more common entities Langerhans cell histiocytosis and Erdheim-Chester disease are established, less common neoplasms in this broad category are poorly characterized. In the current study, we assessed the genomic landscape of these often aggressive histiocytic and dendritic cell neoplasms to identify distinct mutational signatures for each subtype in the current WHO classification system. Methods: 104 histiocytic and dendritic cell neoplasmswere tested during routine clinical care by hybridization capture of 406 cancer-related genes to detect base substitutions, small indels, amplifications (amp), deletions, and rearrangements. Tumor mutational burden (TMB, mutations/Mb) was determined on ~1.1 Mbp of sequenced DNA. Review of pathology reports, histopathology, and patient clinical data was performed. Cases included 48 follicular dendritic cell sarcoma (FDCS), 37 histiocytic sarcoma (HS), 8 interdigitating dendritic cell sarcoma (IDCS), 5 Langerhans cell sarcoma (LCS), 4 indeterminate cell histiocytosis (ICH), 1 fibroblastic reticular cell tumor (FRCT), and 1 inflammatory pseudotumor-like follicular/fibroblastic dendritic cell sarcoma (FDC/FRCS). Results: Pathogenic or likely-pathogenic genomic alterations (GAs) in the four most common sarcoma subgroups are summarized in the Table. CDKN2A and TP53 pathogenic mutations were the most frequent GAs observed in the cohort, present in 27% and 20% of the cases, respectively. Compared to the rest of the cohort, FDCS showed significantly more cases harboring a pathogenic GA in genes involved with NFkB pathway regulation (58% vs. 18%, p
Print ISSN:
0006-4971
Electronic ISSN:
1528-0020
Topics:
Biology
,
Medicine
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