PRRX1-fused mesenchymal neoplasm: A novel PRRX1::NCOA1 fusion transcript.

PRRX1-fused mesenchymal neoplasm is a recently identified, rare subcutaneous soft tissue neoplasm that is characterized by fusion of PRRX1 (exon 1) with NCOA1 (exon 13) in the majority of reported cases. Although initially considered to be fibroblastic, a possibility of neural or neuroectodermal differentiation has been suggested in a subset of cases. We report a 26-year-old female with a 4.0 cm painless mass located in the subcutis of the left thigh. Microscopically, the tumor was well-circumscribed and multinodular and was composed of relatively monomorphic ovoid to spindle cells arranged in loose fascicles, trabeculae, and cords within alternating myxoid and fibrous matrix, and vascularized stroma. Mitotic figures were scarce and necrosis was not observed. By immunohistochemistry, the neoplastic cells demonstrated focal co-expression of S100 protein and SOX10 and were negative for epithelial membrane antigen, smooth muscle actin, desmin, CD34, STAT6, HMB45, Melan-A, and MUC4. The expression of Rb1 was retained. Targeted RNA-sequencing identified a novel transcript fusion of PRRX1 (exon 1)::NCOA1 (exon 15), which was further confirmed by reverse transcription polymerase chain reaction and Sanger sequencing. The tumor was narrowly excised and no tumor recurrence or metastasis was identified after 13 months of follow-up. In summary, we report a new case of PRRX1-fused mesenchymal neoplasm, expanding the molecular genetic spectrum and providing further support for possible neural or neuroectodermal differentiation of this emerging soft tissue tumor entity.

Transcriptional coactivation of NRF2 signaling in cardiac fibroblasts promotes resistance to oxidative stress.

We recently discovered that steroid receptor coactivators (SRCs) SRCs-1, 2 and 3, are abundantly expressed in cardiac fibroblasts (CFs) and their activation with the SRC small molecule stimulator MCB-613 improves cardiac function and dramatically lowers pro-fibrotic signaling in CFs post-myocardial infarction. These findings suggest that CF-derived SRC activation could be beneficial in the mitigation of chronic heart failure after ischemic insult. However, the cardioprotective mechanisms by which CFs contribute to cardiac pathological remodeling are unclear. Here we present studies designed to identify the molecular and cellular circuitry that governs the anti-fibrotic effects of an MCB-613 derivative, MCB-613-10-1, in CFs. We performed cytokine profiling and whole transcriptome and proteome analyses of CF-derived signals in response to MCB-613-10-1. We identified the NRF2 pathway as a direct MCB-613-10-1 therapeutic target for promoting resistance to oxidative stress in CFs. We show that MCB-613-10-1 promotes cell survival of anti-fibrotic CFs exposed to oxidative stress by suppressing apoptosis. We demonstrate that an increase in HMOX1 expression contributes to CF resistance to oxidative stress-mediated apoptosis via a mechanism involving SRC co-activation of NRF2, hence reducing inflammation and fibrosis. We provide evidence that MCB-613-10-1 acts as a protectant against oxidative stress-induced mitochondrial damage. Our data reveal that SRC stimulation of the NRF2 transcriptional network promotes resistance to oxidative stress and highlights a mechanistic approach toward addressing pathologic cardiac remodeling.

The multifaceted therapeutic value of targeting steroid receptor coactivator-1 in tumorigenesis.

Steroid receptor coactivator-1 (SRC-1, also known as NCOA1) frequently functions as a transcriptional coactivator by directly binding to transcription factors and recruiting to the target gene promoters to promote gene transcription by increasing chromatin accessibility and promoting the formation of transcriptional complexes. In recent decades, various biological and pathological functions of SRC-1 have been reported, especially in the context of tumorigenesis. SRC-1 is a facilitator of the progression of multiple cancers, including breast cancer, prostate cancer, gastrointestinal cancer, neurological cancer, and female genital system cancer. The emerging multiorgan oncogenic role of SRC-1 is still being studied and may not be limited to only steroid hormone-producing tissues. Growing evidence suggests that SRC-1 promotes target gene expression by directly binding to transcription factors, which may constitute a novel coactivation pattern independent of AR or ER. In addition, the antitumour effect of pharmacological inhibition of SRC-1 with agents including various small molecules or naturally active compounds has been reported, but their practical application in clinical cancer therapy is very limited. For this review, we gathered typical evidence on the oncogenic role of SRC-1, highlighted its major collaborators and regulatory genes, and mapped the potential mechanisms by which SRC-1 promotes primary tumour progression.

Mesenchymal Stem Cell-conditioned Medium Protecting Renal Tubular Epithelial Cells by Inhibiting Hypoxia-inducible Factor-1α and Nuclear Receptor Coactivator-1.

BACKGROUND: Acute kidney injury (AKI) is characterized by inflammatory infiltration and damage and death of renal tubular epithelial cells (RTECs), in which hypoxia plays an important role. Deferoxamine (DFO) is a well-accepted chemical hypoxia-mimetic agent. Mesenchymal stem cell-conditioned medium (MSC-CM) can reduce local inflammation and repair tissue. In this study, we explored the effect and molecular mechanism of MSC-CM-mediated protection of RTECs under DFO-induced hypoxia. METHODS: Rat renal proximal tubule NRK-52E cells were treated with different concentrations of DFO for 24 hours, followed by evaluation of RTEC injury, using a Cell Counting Kit-8 (CCK-8) to detect cell viability and western blotting to evaluate the expression of transforming growth factor- beta 1 (TGF-ß1), α-smooth muscle actin (α-SMA), and hypoxia-inducible factor-1 alpha (HIF-1α) in NRK-52E cells. Then, three groups of NRK-52E cells were used in experiments, including normal control (NC), 25 µM DFO, and 25 µM DFO + MSC-CM. MSC-CM was obtained from the human umbilical cord. MSC-CM was used to culture cells for 12 hours before DFO treatment, then fresh MSC-CM and 25 µM DFO were added, and cells were cultured for another 24 hours before analysis. RESULTS: Western blotting and cellular immunofluorescence staining showed culture of NRK-52E cells in 25 µM DFO for 24 hours induced HIF-1α and nuclear receptor coactivator-1 (NCoA-1), simulating hypoxia. MSC-CM could inhibit the DFO-induced up-regulation of α-SMA, TGF-ß1, HIF-1α and NCoA-1. CONCLUSION: Our results suggest that MSC-CM has a protective effect on RTECs by down-regulating HIF-1α and NCoA-1, which may be the harmful factors in renal injury.

Active Estrogen-Succinate Metabolism Promotes Heme Accumulation and Increases the Proliferative and Invasive Potential of Endometrial Cancer Cells.

Uterine endometrial cancer (UEC) is an estrogen-related tumor. Succinate and heme metabolism play important roles in the progression of multiple tumors. However, the relationship between estrogen, succinate, and heme metabolism and related regulatory mechanisms remain largely unknown. In this study, we observed that the expression of aminolevulinate delta synthase 1 (ALAS1) and solute carrier family member 38 (SLC25A38) in UEC tissues is significantly higher than that in normal tissues. Further analysis showed that estrogen and succinate increased the expression of ALAS1 and SLC25A38 in uterine endometrial cancer cells (UECC), and the administration of succinate upregulated the level of the estrogen receptor (ER). Silencing nuclear receptor coactivator 1 (NCOA1) reversed the effects of estrogen and succinate via downregulation of ALAS1 expression. Additionally, exposure of UECC to heme increased cell viability and invasiveness, while silencing the NCOA1 gene weakened this effect. These findings revealed that estrogen and succinate can synergistically increase the expression of ALAS1 and SLC25A38 via the ERß/NCOA1 axis, promoting heme accumulation and increasing the proliferative and invasive potential of UECC.

"PRRX1-rearranged mesenchymal tumors": expanding the immunohistochemical profile and molecular spectrum of a recently described entity with the proposed revision of nomenclature.

Since the publication of the 2020 World Health Organization classification of soft tissue and bone tumors, the classification of "fibroblastic" tumors has expanded to include a novel subset of tumors characterized by PRRX1::NCOA1/2 gene fusions. These tumors defy conventional classification and are morphologically distinct, characterized by a multi-nodular growth of bland spindle cells suspended in a myxo-collagenous stroma with mild cytologic atypia, "staghorn-like" vessels, and variable perivascular hyalinization. Mitotic activity is rare, and necrosis is not identified. Herein, we present six additional cases of PRRX1-rearranged mesenchymal tumors, including five cases with PRRX1::NCOA1 fusion and one case with PRRX1::KMT2D fusion. Three cases (3/6, 50%) demonstrated focal co-expression of S100 protein and SOX10, thereby expanding the immunohistochemical profile of this emerging entity. Like prior reported cases, there was no evidence of malignant behavior on short-term follow-up. The novel fusion, PRRX1::KMT2D, further expands the molecular spectrum of this entity and leads to a proposed revision of the provisional nomenclature to "PRRX1-rearranged mesenchymal tumor" to both accommodate non-NCOA1/2 fusion partners and allow for the possibility of partial neural or neuroectodermal differentiation.

Spindle Cell Sarcoma of the Uterus Harboring MEIS1::NCOA1 Fusion Gene and Mimicking Endometrial Stromal Sarcoma.

MEIS1::NCOA1/2 sarcomas are a newly recognized group of exceedingly rare low-grade spindle cell sarcomas that often involve the genitourinary and gynecologic tracts. Due to its deceptively low-grade morphology and the non-specific immunoprofile, these neoplasms may pose a diagnostic challenge by histologically mimicking other entities such as endometrial stromal sarcoma, smooth muscle tumor, or uterine perivascular epithelioid cell tumor (PEComa). Histologically, MEIS1::NCOA1/2 sarcomas typically show spindle cell proliferation with hyperchromatic nuclei and a generalized cytologic uniformity, arranged in short fascicles and exhibiting alternating zones of hypo- and hypercellularity. Among the previously reported cases, molecular analysis revealed the MEIS1::NCOA2 fusion as the most commonly detected fusion gene, whereas the MEIS1::NCOA1 fusion gene has been reported in only a single case that involved kidney. Herein we report the first case of uterine sarcoma harboring the MEIS1::NCOA1 fusion gene that was initially misclassified as low-grade endometrial stromal sarcoma, demonstrating its clinicopathologic features, and highlighting the essential role of molecular pathology to arrive at the accurate diagnosis that may alter disease classification and inform therapy.

hsa-miR-23a~27a~24-2 cluster members inhibit aggressiveness of breast cancer cells by commonly targeting NCOA1, NLK and RAP1B.

Targeted therapy is receiving considerable attention from the researchers around the globe owing to the increased drug-resistance and incidences of cancer recurrences. MicroRNAs (miRNAs) exhibits tremendous potential as a candidate for molecular targeted therapy in cancer. Unfortunately, majority of research related to microRNAs are focussed on either a particular miRNA or a set of unrelated miRNAs. There is lack of holistic knowledge on differential co-expression of miRNA clusters in regulating the gene expression under physiological conditions. Previously, we reported the cooperative effect of hsa-miR-23a~27a~24-2 cluster in inducing ER (Endoplasmic Reticulum) stress-mediated apoptotic cell death of HEK cells. In the present study, we have investigated the common anti-cancer effects of individual members of this cluster. Our in silico analysis identified twelve common target genes distributed across three independent clusters. Furthermore, we found NCOA1, NLK, and RAP1B to fall in a single cluster with NCOA1 as a central hub molecule. Prognostic analysis showed profound involvement of these three genes in the breast cancer progression and metastasis. We further demonstrated that alteration in the levels of individual members of miR-23a~27a~24-2 cluster commonly regulates the invasive migration of breast cancer cells by modulating EMT and cytoskeletal pathway proteins. Our results reveal a new insight into the therapeutic potential of individual members of the pro-apoptotic hsa-miR-23a~27a~24-2 cluster family against metastatic breast cancer.

The NCOA1-CBP-NF-κB transcriptional complex induces inflammation response and triggers endotoxin-induced myocardial dysfunction.

Inflammatory pathways represented by TLR4/NF-κB (Toll-like receptor 4/Nuclear factor-κB) axis signaling are activated in the pathogenesis of endotoxin-induced myocardial dysfunction (EIMD). However, the underlying mechanism by which NF-κB coordinates with other transcriptional coactivators/corepressors to regulate the expression of proinflammatory cytokine genes remains unclear. We established an EIMD-mouse model by intraperitoneal injection of lipopolysaccharides (LPS), and we discovered that NCOA1 (nuclear receptor coactivator 1) assembled with CBP (CREB binding protein) and NF-κB subunits to form a transcriptional complex that specifically bound to promoters of proinflammatory cytokine genes to activate their expression. LPS treatment also inhibited DNMT1 (DNA methyltransferase 1) expression, thereby decreasing DNA methylation of a CpG island located on the promoter of NCOA1 and causing NCOA1 overexpression. Screening small molecules that abolished NCOA1-CBP interaction in a yeast system identified a compound PSSM2126 that effectively blocked the NCOA1-CBP interaction in vitro and in vivo. Administration of PSSM2126 to EIMD mice significantly alleviated the inflammation response and improved cardiac function. Collectively, our results reveal that an NCOA1-dependent transactivation mechanism can regulate proinflammatory cytokine expression, thereby improving our understanding of the activation of NF-κB targets. The promising inhibition of the NCOA1-CBP interaction by PSSM2126 may provide a new therapeutic option for EIMD.

Loss of RUBCN/rubicon in adipocytes mediates the upregulation of autophagy to promote the fasting response.

Upon fasting, adipocytes release their lipids that accumulate in the liver, thus promoting hepatic steatosis and ketone body production. However, the mechanisms underlying this process are not fully understood. In this study, we found that fasting caused a substantial decrease in the adipose levels of RUBCN/rubicon, a negative regulator of macroautophagy/autophagy, along with an increase in autophagy. Adipose-specific rubcn-knockout mice exhibited systemic fat loss that was not accelerated by fasting. Genetic inhibition of autophagy in adipocytes in fasted mice led to a reduction in fat loss, hepatic steatosis, and ketonemia. In terms of mechanism, autophagy decreased the levels of its substrates NCOA1/SRC-1 and NCOA2/TIF2, which are also coactivators of PPARG/PPARγ, leading to a fasting-induced reduction in the mRNA levels of adipogenic genes in adipocytes. Furthermore, RUBCN in adipocytes was degraded through the autophagy pathway, suggesting that autophagic degradation of RUBCN serves as a feedforward system for autophagy induction during fasting. Collectively, we propose that loss of adipose RUBCN promotes a metabolic response to fasting via increasing autophagic activity.

The emerging PRRX1-NCOA fibroblastic neoplasm: a combined reappraisal of published tumors and two new cases.

Nuclear receptor coactivator (NCOA) family gene fusions have been increasingly discovered in diverse mesenchymal neoplasms, while PRRX1-NCOA-fused fibroblastic tumors still remain insufficiently characterized. We herein present two additional PRRX1-NOCA1-positive cases sharing lobulated hypocellular growth of innocuous spindle-to-stellate cells in a fibromyxoid stroma enriched with polymorphous vessels. A constellation of low cellularity, alternating myxocollagenous matrix, bland cytomorphology, and, especially, unusual collagenous rosettes in one case were morphologically reminiscent of low-grade fibromyxoid sarcoma. In both cases, immunoprofiles were similarly nondescript and negative for all diagnostic markers, including MUC4, emphasizing the diagnostic value of molecular testing. Review of published and current cases highlights a striking predominance of PRRX1-NCOA1, unusual collagenous rosettes, and favorable behavior in this emerging fibroblastic tumor type.

PAX3-NCOA1 alveolar rhabdomyosarcoma of the tongue: A rare entity with challenging diagnosis and management.

Alveolar rhabdomyosarcoma (ARMS) is associated with PAX3/PAX7-FOXO1 fusion, which confers specific clinic and biologic characteristics with inferior outcomes. A minority of tumors still histologically classified as "true" ARMS lack the canonical PAX-FOXO1 fusion but have new molecular alterations. We present the first case of PAX3-NCOA1 ARMS with clinical data and follow-up in a two-year-old girl with ARMS of the tongue and nodal extension, treated with chemotherapy, hemi glossectomy, lymph node dissection, and brachytherapy to conserve oral function and limit long-term sequelae. Given the rarity of such variant fusion in ARMS, international collaboration is required to evaluate its prognostic value.

PRRX1-NCOA1-rearranged fibroblastic tumour: a clinicopathological, immunohistochemical and molecular genetic study of six cases of a potentially under-recognised, distinctive mesenchymal tumour.

AIMS: PRRX1-NCOA1-rearranged fibroblastic tumour is a recently described, rare mesenchymal tumour. Only four cases have been previously reported. The aim of this article is to report six additional cases of this unusual mesenchymal neoplasm, with an emphasis on its differential diagnosis. METHODS AND RESULTS: The six cases were from three females and three males (age, 20-49 years; median, 42 years). Three tumours were located on the abdominal wall; two from the shoulder/axillary areas, and one on the lateral hip. All presented as slow-growing subcutaneous nodules, ranging from 26 to 55 mm (median, 40 mm). The tumours consisted of circumscribed, variably cellular nodules composed of relatively bland plump spindled to epithelioid cells arranged singly, in cords, and occasionally in nests, embedded in hyalinised and collagenous stroma. Small hypocellular myxoid zones with ropey collagen fibres were present, as were irregularly dilated, gaping, crescent-shaped or staghorn-like thin-walled vessels, best appreciated at the periphery. Immunohistochemistry for CD34, S100, MUC4 and STAT6 was consistently negative. RNA-sequencing revealed PRRX1-NCOA1 fusions in all cases. Of the four cases with limited follow-up (1.5-4 months), none recurred following local surgical excision. CONCLUSIONS: The morphological features of PRRX1-NCOA1-rearranged fibroblastic tumour overlap with those of RB1-deficient soft-tissue tumours, solitary fibrous tumour, and low-grade fibromyxoid sarcoma/sclerosing epithelioid fibrosarcoma. This differential diagnosis can be resolved with a combination of careful morphological study and the application of a panel of immunostains, although molecular genetic study is most definitive. The natural history of PRRX1-NCOA1-rearranged fibroblastic tumour appears to be quite favourable, although longer-term study of a larger number of cases is warranted.

A Novel Mouse Model for SNP in Steroid Receptor Co-Activator-1 Reveals Role in Bone Density and Breast Cancer Metastasis.

The steroid receptor coactivator-1 (SRC-1) is a nuclear receptor co-activator, known to play key roles in both estrogen response in bone and in breast cancer metastases. We previously demonstrated that the P1272S single nucleotide polymorphism (SNP; P1272S; rs1804645) in SRC-1 decreases the activity of estrogen receptor in the presence of selective estrogen receptor modulators (SERMs) and that it is associated with a decrease in bone mineral density (BMD) after tamoxifen therapy, suggesting it may disrupt the agonist action of tamoxifen. Given such dual roles of SRC-1 in the bone microenvironment and in tumor cell-intrinsic phenotypes, we hypothesized that SRC-1 and a naturally occurring genetic variant, P1272S, may promote breast cancer bone metastases. We developed a syngeneic, knock-in mouse model to study if the SRC-1 SNP is critical for normal bone homeostasis and bone metastasis. Our data surprisingly reveal that the homozygous SRC-1 SNP knock-in increases tamoxifen-induced bone protection after ovariectomy. The presence of the SRC-1 SNP in mammary glands resulted in decreased expression levels of SRC-1 and reduced tumor burden after orthotopic injection of breast cancer cells not bearing the SRC-1 SNP, but increased metastases to the lungs in our syngeneic mouse model. Interestingly, the P1272S SNP identified in a small, exploratory cohort of bone metastases from breast cancer patients was significantly associated with earlier development of bone metastasis. This study demonstrates the importance of the P1272S SNP in both the effect of SERMs on BMD and the development of tumor in the bone.

Ependymoma-like tumor with mesenchymal differentiation harboring C11orf95-NCOA1/2 or -RELA fusion: A hitherto unclassified tumor related to ependymoma.

Recurrent fusion genes involving C11orf95, C11orf95-RELA, have been identified only in supratentorial ependymomas among primary CNS tumors. Here, we report hitherto histopathologically unclassifiable high-grade tumors, under the tentative label of "ependymoma-like tumors with mesenchymal differentiation (ELTMDs)," harboring C11orf95-NCOA1/2 or -RELA fusion. We examined the clinicopathological and molecular features in five cases of ELTMDs. Except for one adult case (50 years old), all cases were in children ranging from 1 to 2.5 years old. All patients presented with a mass lesion in the cerebral hemisphere. Histologically, all cases demonstrated a similar histology with a mixture of components. The major components were embryonal-appearing components forming well-delineated tumor cell nests composed of small uniform cells with high proliferative activity, and spindle-cell mesenchymal components with a low- to high-grade sarcoma-like appearance. The embryonal-appearing components exhibited minimal ependymal differentiation including a characteristic EMA positivity and tubular structures, but histologically did not fit with ependymoma because they lacked perivascular pseudorosettes, a histological hallmark of ependymoma, formed well-delineated nests, and had diffuse and strong staining for CAM5.2. Molecular analysis identified C11orf95-NCOA1, -NCOA2, and -RELA in two, one, and two cases, respectively. t-distributed stochastic neighbor embedding analysis of DNA methylation data from two cases with C11orf95-NCOA1 or -NCOA2 and a reference set of 380 CNS tumors revealed that these two cases were clustered together and were distinct from all subgroups of ependymomas. In conclusion, although ELTMDs exhibited morphological and genetic associations with supratentorial ependymoma with C11orf95-RELA, they cannot be regarded as ependymoma. Further analyses of more cases are needed to clarify their differences and similarities.

Can network pharmacology identify the anti-virus and anti- inflammatory activities of Shuanghuanglian oral liquid used in Chinese medicine for respiratory tract infection?

INTRODUCTION: Shuanghuanglian (SHL) oral liquid is a well-known traditional Chinese medicine preparation administered for respiratory tract infections in China. However, the underlying pharmacological mechanisms remain unclear. The present study aims to determine the potential pharmacological mechanisms of SHL oral liquid based on network pharmacology. METHODS: Network pharmacology-based strategy including collection and analysis of putative compounds and target genes, network construction, Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway, and Gene Ontology (GO) enrichment, identification of key compounds and target genes, and molecule docking was performed in this study. RESULTS: A total of 82 bioactive compounds and 226 putative target genes of SHL oral liquid were collected. Of note, 28 hub target genes including 4 major hub target genes: estrogen receptor 1 (ESR1), nuclear receptor coactivator 2 (NCOA2), nuclear receptor coactivator 1 (NCOA1), androgen receptor (AR) and 5 key compounds (quercetin, luteolin, baicalein, kaempferol and wogonin) were identified based on network analysis. The hub target genes mainly enriched in pathways including PI3K-Akt signaling pathway, human cytomegalovirus infection, and human papillomavirus infection, which could be the underlying pharmacological mechanisms of SHL oral liquid for treating diseases. Moreover, the key compounds had great molecule docking binding affinity with the major hub target genes. CONCLUSION: Using network pharmacology analysis, SHL oral liquid was found to contain anti-virus, anti-inflammatory, and "multi-compounds and multi-targets" with therapeutic actions. These findings may provide a valuable direction for further clinical application and research.

NEMP1 Promotes Tamoxifen Resistance in Breast Cancer Cells.

Breast cancer (BC) is a worldwide malignant and a leading death cancer in women. Studies have shown that adjuvant tamoxifen reduces the recurrence rate and metastasis in BC. Even though tamoxifen has been used for the therapy of BC for decades, the resistance of it on BC cells could not be ignored. In this study, we first established a tamoxifen-resistant BC cell line and then demonstrated the overexpression of nuclear envelope integral membrane protein 1 (NEMP1) in the tamoxifen-resistant BC cells. Moreover, through a cell viability assay combined with depletion or overexpression technology, we addressed the important role of NEMP1 for the tamoxifen resistance in BC cells. Importantly, we further revealed that NEMP1 modulated tamoxifen resistance by regulating nuclear receptor coactivator 1 (NCOA1). In general, NEMP1 shows responsibility for the resistance of tamoxifen through regulating NCOA1 in BC cells. These results broaden the understanding of the tamoxifen resistance during the chemotherapy in BC and may provide new therapy method for BC.

PRRX-NCOA1/2 rearrangement characterizes a distinctive fibroblastic neoplasm.

Fibroblastic/myofibroblastic neoplasms represent a broad, and occasionally diagnostically challenging, category of soft tissue neoplasms. A subset of these tumors defy conventional classification. However, with the advent of next-generation sequencing, the identification of disease-defining molecular alterations is gradually improving their subclassification. Following identification of two index cases of a distinctive fibroblastic neoplasm with a fusion gene involving PRRX1 and NCOA1, we performed a retrospective review to further characterize this entity. We identified two additional cases, including one with a fusion between PRRX1 and NCOA2. The average patient age was 38 years, and three patients were female. Two tumors occurred on the neck, and the others involved the groin and thigh. Tumors were centered in the subcutis and ranged from 2.3 to 14.0 cm (average 5.8 cm). Morphologically, they were predominantly hypocellular, with focal hypercellularity. They were composed of monomorphic spindle-stellate cells with a vague fascicular pattern. The nuclei were bland with only rare mitotic activity, and occasional multinucleation. The intervening stroma was typically abundant and ranged from myxoid to collagenous, with frequent rope-like collagen bundles. Three of the cases had a prominent vasculature ranging from numerous small curvilinear vessels to ectatic and branching staghorn-like vessels. Immunohistochemistry was negative for desmin, smooth muscle actin, S100, CD34, keratin, and epithelial membrane antigen. Each of the patients was treated by simple excision and none of the tumors were associated with local recurrence or metastasis. Based on their unique morphological and molecular attributes, we believe this represents a novel fibroblastic tumor for which we have tentatively proposed the name "PRRX-NCOAx-rearranged fibroblastic tumor."

NCOA1-ALK: a novel ALK rearrangement in one lung adenocarcinoma patient responding to crizotinib treatment.

The heterogeneity of ALK tyrosine-kinase inhibitor (TKI) responses poses a puzzling question to clinicians. Different variants of ALK rearrangements might be one of the mechanisms explaining this phenomenon. Therefore, identifying specific fusion forms is crucial to clinical practice. This case report assesses the clinical efficacy of an ALK-TKI in a new ALK-rearrangement variant. Next-generation sequencing was performed in tumor tissue of one lung adenocarcinoma patient, and one new fusion form of an ALK rearrangement (NCOA1-ALK) was identified. This patient had progression-free survival >18 months with crizotinib treatment. Our findings provide valuable information about responses to crizotinib in patients with this form of ALK rearrangement and better understanding of ALK-TKI applications.

Biphenotypic sinonasal sarcoma: demographics, clinicopathological characteristics, molecular features, and prognosis of a recently described entity.

Biphenotypic sinonasal sarcoma (BSNS) is a recently recognized type of sarcoma arising exclusively in the sinonasal tract displaying unique clinical course, histopathology, and genetics. Due to its rarity, only case series and case reports are available. In order to provide an overview of the current understanding of this disease, we present a comprehensive review of the literature and present three previously unreported cases of BSNS. A total of 55 genetically characterized and 41 cases without molecular data were identified in the literature. Two-thirds of patients were female and the peak incidence was in the fifth decade. Fatal outcome was rare (two cases with intracranial extension) and local recurrence occurred in 31.6%, all occurring within 5 years after initial treatment. Histologically, BSNS is highly cellular in the majority of cases and composed of fascicles of spindle cells, with entrapped hyperplastic surface epithelium being a frequent finding. The immunohistochemical profile is characteristic due to the biphasic nature of this lesion, with shared features of both myogenic and neural origin. Rhabdomyoblastic differentiation is apparent in a subset of cases. The most common genetic event is the PAX3-MAML3 fusion (58.6%) but isolated PAX3 rearrangement (19.2%), absence of rearrangements (9.1%), PAX3-FOXO1 (8.1%), PAX3-NCOA1 (4%), and isolated MAML3 rearrangement (2%) have also been reported. In conclusion, the recognition of BSNS is crucial due to its relatively indolent clinical course. A selected immunohistochemical panel and/or molecular confirmation can be used to aid in appropriate diagnosis and consequently in prognostication and to avoid overtreatment with chemotherapy regimens used in its mimics.