Project description:14-3-3 proteins are ubiquitously expressed regulators of various cellular functions, including proliferation, metabolism, and differentiation, and altered 14-3-3 expression is associated with development and progression of cancer. We report a transforming 14-3-3 oncoprotein, which we identified through conventional cytogenetics and whole-transcriptome sequencing analysis as a highly recurrent genetic mechanism in a clinically aggressive form of uterine sarcoma: high-grade endometrial stromal sarcoma (ESS). The 14-3-3 oncoprotein results from a t(10;17) genomic rearrangement, leading to fusion between 14-3-3ε (YWHAE) and either of two nearly identical FAM22 family members (FAM22A or FAM22B). Expression of YWHAE-FAM22 fusion oncoproteins was demonstrated by immunoblot in t(10;17)-bearing frozen tumor and cell line samples. YWHAE-FAM22 fusion gene knockdowns were performed with shRNAs and siRNAs targeting various FAM22A exons in an t(10;17)-bearing ESS cell line (ESS1): Fusion protein expression was inhibited, with corresponding reduction in cell growth and migration. YWHAE-FAM22 maintains a structurally and functionally intact 14-3-3ε (YWHAE) protein-binding domain, which is directed to the nucleus by a FAM22 nuclear localization sequence. In contrast to classic ESS, harboring JAZF1 genetic fusions, YWHAE-FAM22 ESS display high-grade histologic features, a distinct gene-expression profile, and a more aggressive clinical course. Fluorescence in situ hybridization analysis demonstrated absolute specificity of YWHAE-FAM22A/B genetic rearrangement for high-grade ESS, with no fusions detected in other uterine and nonuterine mesenchymal tumors (55 tumor types, n = 827). These discoveries reveal diagnostically and therapeutically relevant models for characterizing aberrant 14-3-3 oncogenic functions.
Project description:NUTM1-rearranged tumors are defined by the presence of a gene fusion between NUTM1 and various gene partners and typically follow a clinically aggressive disease course with poor outcomes despite conventional multimodality therapy. NUTM1-rearranged tumors display histologic features of a poorly differentiated carcinoma with areas of focal squamous differentiation and typically express the BRD4-NUTM1 fusion gene defining a distinct clinicopathologic entity-NUT carcinoma (NC). NCs with mesenchymal differentiation have rarely been described in the literature. In this report, we describe the characterization of two cases of high-grade spindle cell sarcoma harboring a novel MGA-NUTM1 fusion. Whole-genome sequencing identified the presence of complex rearrangements resulting in a MGA-NUTM1 fusion gene in the absence of other significant somatic mutations. Genetic rearrangement was confirmed by fluorescence in situ hybridization, and expression of the fusion gene product was confirmed by transcriptomic analysis. The fusion protein was predicted to retain nearly the entire protein sequence of both MGA (exons 1-22) and NUTM1 (exons 3-8). Histopathologically, both cases were high-grade spindle cell sarcomas without specific differentiation markers. In contrast to typical cases of NC, these cases were successfully treated with aggressive local control measures (surgery and radiation) and both patients remain alive without disease. These cases describe a new subtype of NUTM1-rearranged tumors warranting expansion of diagnostic testing to evaluate for the presence of MGA-NUTM1 or alternative NUTM1 gene fusions in the diagnostic workup of high-grade spindle cell sarcomas or small round blue cell tumors of ambiguous lineage.
Project description:Uterine sarcomas are a group of rare malignant tumors of mesenchymal tissue of the uterus, and their diagnosis is often difficult because they have variable morphologies and no typical immunophenotype. This report describes a 48-year-old woman who underwent laparoscopic myomectomy and relapsed within 5 years with a large mass in the pelvic cavity. Morphologically, the tumor was composed of oval cells and small arteries, and the cells showed moderate to severe atypia. Immunohistochemical results showed that the tumor cells expressed desmin, smooth muscle actin, and h-caldesmon, which supported myogenic differentiation. They were strongly positive for Cyclin D1, estrogen receptors (ER), and estrogen receptors (PR), supporting their origin from uterine mesenchymal cells. Next-generation sequencing (NGS) revealed a GATAD2B::MMRN1 rearrangement. The patient was diagnosed with uterine sarcoma resembling high-grade endometrial mesenchymal sarcoma with a GATAD2B-MMRN1 fusion. We review the relevant literature and discuss the diagnostic and differential diagnostic points for this disease.
Project description:NUT carcinoma (NC) with mesenchymal differentiation have rarely been described in the literature. In this report, we describe the characterization of two cases of high grade spindle cell sarcoma harboring a novel MGA-NUTM1 fusion. Whole genome sequencing identified the presence of complex rearrangements resulting in a MGA-NUTM1 fusion gene in the absence of other significant somatic mutations. The fusion protein was predicted to retain nearly the entire protein sequence of both MGA (exons 1-22) and NUTM1 (exons 3-8). In contrast to typical cases of NC, these cases were successfully treated with aggressive local control measures (surgery and radiation) and both patients remain alive without disease. These cases describe a new subtype of NUTM1-rearranged tumors warranting expansion of diagnostic testing to evaluate for the presence of MGA-NUTM1 or alternative NUTM1 gene fusions in the diagnostic workup of high grade spindle cell sarcomas or small round blue cell tumors of ambiguous lineage.
Project description:IntroductionSpindle cell sarcomas are rare breast lesions which are difficult to diagnose due to resemblance with other breast lesions. Histopathological examination and immunohistochemical staining are essential for diagnosis.Case presentationWe present a rare case of a 15-year-old female presenting with high-grade rapidly progressive spindle cell sarcoma of the breast, differentiated as phyllodes tumor, with axillary lymph node involvement. Her lesion, on the left breast, measured 16.9 × 10.1 × 13.7 cm. Histology revealed malignant neoplasm arranged in sheets and individual neoplastic cells with an epithelioid to spindled morphology with scant cytoplasm and irregular nuclear membranes. Immunohistochemistry showed weakly positive focal CD-99, and negative WT-1, Myogenin, Desmin, p63, Cytokeratin, Synaptophysin, and CD-34 markers. She was successfully managed with modified radical mastectomy and discharged with regular follow-up advised.ConclusionSpindle cell sarcomas have a very aggressive course and prompt diagnosis, and management is mandatory for better patient outcomes. Modified radical mastectomy is the mainstay of treatment.