Round Cell Research Articles

Translational implications of a novel combination of iPRF and collagen scaffold for proliferation of gingival mesenchymal stem cells.

"Tissue engineering," is a concept that involves the use of scaffolds, cells, and growth factors/signaling molecules in the field of regenerative medicine. The present study was carried out to evaluate the attachment and depth of penetration of the Gingival Mesenchymal Stem Cells (GMSCs) onto the collagen scaffold preconditioned with Fetal Bovine Serum (FBS), Injectable Platelet Rich Fibrin (i-PRF) and a combination of FBS with i-PRF using histological analysis and environmental scanning electron microscopy (ESEM) respectively. In the present study, commercially available collagen membranes were used as scaffolds and divided into 3 groups where Group I was preconditioned with FBS, Group II was preconditioned with i-PRF, and Group III with a combination of FBS and i-PRF. Scaffolds were then seeded with GMSCs and incubated in a CO2 incubator at 37 0C for 7 days. Both histological and ESEM analysis showed proliferation, attachment, and depth of penetration along with the combination of cell morphological changes in all the three groups. In group I cells showed mild depth of penetration along with a round morphological appearance. In group II the cells showed moderate depth of penetration and rounded morphology. In group III maximum depth of penetration was seen along with the round and spheroidal morphology of cells. The combination of the growth media showed the best effect on cell attachment, depth of penetration, and cell morphology. This is the first report demonstrating the effect of the combination of collagen and i-PRF supports the proliferation of GMSCs. Since FBS alone and i-PRF alone exhibited similar cell proliferation it is recommended that i-PRF could be used in clinical scenarios making it xenofree.

BCOR-ITD Rearranged Sarcoma in the Mandible of a 5-Year-Old Child: A Case Report Highlighting Diagnostic Distinction From Odontogenic Fibromyxoma.

The 5th edition of the World Health Organization (WHO) classification of soft tissue and bone has recognized three distinct groups among Ewing-like sarcomas, namely, CIC-rearranged sarcoma, sarcomas with BCOR genetic alterations, and round cell sarcomas with EWSR1:: non-ETS fusions. Sarcomas with BCOR genetic alterations are a distinct clinicopathological group of high-grade tumors, representing 5% of small round cell tumors. BCOR-ITD rearranged tumors commonly manifest as spindle cell sarcomas and many of them display low cellularity with monomorphous cell morphology and myxoid background resembling benign fibroblastic tumors. We present an intriguing case report of a 5-year-old boy diagnosed with a moderately cellular mandibular spindle cell tumor exhibiting BCOR-ITD rearrangement which was initially misdiagnosed as an odontogenic fibromyxoma. This case report illustrates the histological and immunophenotypic findings of BCOR-ITD rearranged sarcoma, requiring a comprehensive immunohistochemical panel and additional molecular tests for accurate diagnosis.

The Capicua C1 Domain is Required for Full Activity of the CIC::DUX4 Fusion Oncoprotein.

Rearrangements between genes can yield neomorphic fusions that drive oncogenesis. Fusion oncogenes are made up of fractional segments of the partner genes that comprise them, with each partner potentially contributing some of its own function to the nascent fusion oncoprotein. Clinically, fusion oncoproteins driving one diagnostic entity are typically clustered into a single molecular subset and are often treated a similar fashion. However, knowledge of where specific fusion breakpoints occur in partner genes, and the resulting retention of functional domains in the fusion, is an important determinant of fusion oncoprotein activity and may differ between patients. This study investigates this phenomena through the example of CIC::DUX4, a fusion between the transcriptional repressor capicua (CIC) and the double homeobox 4 gene (DUX4), which drives an aggressive subset of undifferentiated round cell sarcoma. Using a harmonized dataset of over 100 patient fusion breakpoints from the literature, we show that most bona fide CIC::DUX4 fusions retain the C1 domain, which is known to contribute to DNA binding by wild type CIC. Mechanistically, deletion or mutation of the C1 domain reduces, but does not eliminate, activation of CIC target genes by CIC::DUX4. We also find that expression of C1-deleted CIC::DUX4 is capable of exerting intermediate transformation-related phenotypes compared with those imparted by full-length CIC::DUX4, but was not sufficient for tumorigenesis in a subcutaneous mouse model. In summary, our results suggest a supercharging role for the C1 domain in the activity of CIC::DUX4.

Clinicopathological observation and analysis of uveal leiomyoma

Objective: To analyze the clinical and histopathological features of uveal leiomyoma. Methods: A retrospective study was performed on 19 patients with uveal leiomyoma confirmed by histopathological examination in Beijing Tongren Hospital from January 2018 to May 2023. All patients underwent local resection of the tumor. Clinical data of the patients, such as gender, age, clinical manifestations, tumor location, size, and B-scan ultrasound examinations were collected. The pathological morphological characteristics of the tissue (cell type) and the expression of the immune markers, including smooth muscle actin, actin, and neural cell adhesion molecule (CD56), were evaluated. Results: Among the 19 intraocular leiomyoma patients, there were 5 males and 14 females. The average age was (38.9±13.7) years, ranging from 14 to 64 years. The course of the disease ranged from 1 to 36 months with an average of (9.3±8.7) months. The most common clinical manifestation was blurred vision (12/19), followed by decreased vision (4/19), increased IOP (2/19), and visual occlusion (1/19) in patients. The tumor was located in the ciliary body in 10 female and 5 male patients, including 2 patients with the iris involved, and in the choroid in 4 female patients. Two patients with a history of breast fibronenoma had uveal leiomyoma in the ciliary body and the choroid, respectively. One patient with a history of uterine leiomyoma suffered uveal leiomyoma in the ciliary body. B-scan ultrasonography showed that the tumor was a solid and medium-low echoic lesion with a clear boundary in all eyes. We divided these leiomyomas into two histopathological types: spindle cell type (15/19) and round cell type (4/19). Immunohistochemical staining disclosed smooth muscle actin and actin were expressed in all tumor cells (19/19, 100%), and CD56 was positive in 16 of 19 eyes (84.2%). The positive expression rates of estrogen and progesterone were 0/19 and 2/19. During the follow-up of 7 to 71 months after surgery, no tumor metastasis occurred. Only 1 male patient had tumor recurrence. Conclusions: The most common site of uveal leiomyoma is the ciliary body, the major clinical manifestation is blurred vision, and the prognosis is good. Most of the tumors are spindle cell tumors, with myogenic and neurogenic histological characteristics. Although uveal leiomyoma is more frequently found in women of reproductive age, it shows no significant correlation with estrogen and progestational hormones.

BIOM-41. HMGB2 IS A CANDIDATE PROGNOSTIC BIOMARKER IN BOTH ADULT AND PEDIATRIC DIFFUSE GLIOMAS

Abstract Few prognostic molecular markers are common to pediatric- and adult diffuse gliomas (PDG and ADG). HMGB2 is a protein expressed in human brain development and in de-differentiated high-grade gliomas (HGG), which we have recently described as a putative prognostic and predictive biomarker in ADG, associated with proliferative activity and EIF2 signaling pathway upregulation. Additionally, we showed that HMGB2 shRNA knockdown (HMGB2-KD) reduced cell proliferation and colony formation, and radio-sensitized ADG cell lines. Aims: To assess the prognostic potential of HMGB2 in PDG and its association with stemness. METHODS 1) We singled out HMGB2 from proteomic profiles of an independent PDG cohort previously associated with EIF2 and MYCN signaling upregulation for survival analysis. 2) PDG cells SF188 were de-differentiated with substitution of DMEM by a neurobasal (NB) medium devoid of serum for stemness association studies. 3) We generated HMGB2-KD clones of PDG cell lines SF188 (grown in DMEM and NB) and KNS42 with 3 different shRNAs. RESULTS HMGB2 expression was significantly related to histological grade in PDG (grade 3 vs. grade 2 and grade 4 vs. grade 2: fold change= 8.16 and 9.39; p=0.0045 and <0.001; FDR= 0.04 and 0.0006, respectively) and survival (p=0.004, FDR=0.142 for PFS and p=0.03, FDR=0.291 for OS), in a Cox model including age and grade as covariables. Compared with cells growing in DMEM, SF188 cells growing in NB medium had a morphological change from stellate cells to round cells growing in spheres, with 2-fold increase in C-MYC and HMGB2 expression by Western analysis. HMGB2-KD resulted in >90% reduction of HMGB2 expression in SF188 and >70% in KNS42. CONCLUSION Collectively, our preliminary results suggest that HMGB2 is associated with stemness, has similar roles in PDG and ADG, and may be validated as prognostic/predictive biomarker in both adult and pediatric populations. Mechanistic studies of radiation response are underway.

Adult supratentorial peripheral primitive neuroectodermal tumor with multiple metastases: a case report and literature review

BackgroundIntracranial primitive neuroectodermal tumors (PNETs) are characterized by poorly differentiated, highly malignant, aggressive small round tumor cells originating from the central and peripheral nervous systems.Case presentationA 25-year-old Chinese woman experienced sudden onset headache, vomiting, and severe anemia. Imaging examinations revealed a mass in the left parietal occipital lobe. Following microsurgery, histological confirmation revealed the tumor to be pPNET. Postoperative computed tomography (CT) showed multiple metastases in the lung, liver, and retroperitoneal lymph node. Unfortunately, she died of tumor cachexia 1 month after chemotherapy.ConclusionsDue to the rare presentation of pPNET, pPNET would be misdiagnosed without the histological diagnosis. Here, we aimed to provide clinicians with information about the treatment and relevant literature of pPNET.

Histopathological diagnosis of pulmonary sclerosing pneumocytoma in needle biopsy specimens

Objective: To investigate the diagnostic features of pulmonary sclerosing pneumocytoma (PSP) in needle biopsy specimens so as to improve the preoperative diagnostic accuracy and to prevent misdiagnoses. Methods: A total of 79 needle biopsy cases confirmed as PSP in surgical resection specimens were collected in the First Affiliated Hospital of Zhengzhou University, Zhengzhou, China from January 2015 to January 2023. A retrospective analysis was conducted to investigate the clinical, pathological, and immunohistochemical characteristics of PSP. Results: Among the 79 cases, there were 8 males and 71 females, with an age range of 14 to 67 years (median 47 years). Among the 79 needle biopsy cases of PSP, 5 cases were initially misdiagnosed as adenocarcinoma and 1 as carcinoid preoperatively, while the remaining 73 cases were correctly diagnosed. 84.8% (67/79) of the PSP presented with well-defined, homogeneous, solitary solid tumors on chest imaging. Morphologically, 26.6% (21/79) of the PSP mainly showed a single histological component, 67.1% (53/79) contained two histological components, and 6.3% (5/79) contained three histological components. There were no cases containing all four histological components simultaneously. The tumor was composed of cuboidal cells on the surface and round cells in the stroma and lacked significant cytological atypia and mitotic figures. Some cases exhibited variations in histology and cellular morphology, such as glandular spaces (58.2%, 46/79), sclerotic papillae (46.8%, 37/79), hypercellularity (16.5%, 13/79), and cytological atypia (24.1%, 19/79). Immunophenotyping indicated that both tumor cell types expressed TTF1, EMA and β-catenin, while surface cells expressed pan-cytokeratin and Napsin A, and stromal cells expressed vimentin. In some cases, ER and PR were also expressed. Conclusions: When diagnosing PSP in needle biopsy specimens, the key to avoiding misdiagnosis is recognizing the presence of dual-cell populations within the tumor. The useful clues include presence of cellular papillae, mild cellular atypia, morphological diversity, interstitial foam-like cell aggregates, and prominent background hemorrhage and sclerosis. The characteristic immunophenotype and middle-aged female predilection are also helpful for the diagnosis of PSP.

Aggressive Pediatric Primitive Round Cell Tumors with MN1::ZNF341 Fusion: A Mimic of Neuroblastoma.

Neuroblastoma is one of the most common tumors in young children, arising from the adrenal medulla or paraspinal sympathetic ganglia. We describe primitive round cell tumors presenting in three patients less than 1.5years old, with striking clinical and pathologic similarities to neuroblastoma. Unlike neuroblastoma, however, these primitive tumors did not show specific histologic or immunophenotypic evidence of neuroblastic differentiation, and harbored a MN1::ZNF341 fusion. All patients progressed through neuroblastoma therapy and ultimately died of disease. These highly aggressive tumors mimicking neuroblastoma appear to be a novel and distinctive entity in need of further characterization.

Superficial Neurocristic FET::ETS Fusion Tumor: Expanding the Clinicopathological and Molecular Genetic Spectrum of a Recently Described Entity

Superficial neurocristic EWSR1::FLI1 fusion tumor is a very recently described, clinically indolent tumor of the skin and superficial soft tissues, which differs in essentially all ways from Ewing sarcoma, despite harboring an identical fusion event. The EWSR1 and FLI1 genes are members of the FET and ETS gene family, respectively, and very rare examples of Ewing sarcoma harbor alternative FET::ETS fusion events, such as EWSR1::ERG, FUS::FLI1, FUS::ERG, EWSR1::ETV4 and others. We report 5 new cases of this very rare entity, harboring in 3 cases alternative FET::ETS fusion events. The tumors occurred in 2 males and 3 females (median age 14 years; range 8-69 years) and presented as solitary dermal/ subcutaneous masses of the thigh, foot, shoulder, arm and back (median size 1.8 cm; range: 1-2 cm). All patients underwent wide excisions; one received adjuvant chemotherapy. Clinical follow-up on 3 patients (median: 24 months; range: 18-31 months) showed all to be without disease. Morphologically, all tumors displayed typical features of this entity as described, with nests of cytologically bland, diffusely S100 protein/SOX10-positive round cells without mitotic activity, surrounded by fibrous bands containing spindled cells with similar nuclear features. The tumors also showed membranous CD99 (4/5) and nuclear NKX2.2 (3/3) expression. RNA sequencing (4 cases) demonstrated FUS::FLI1, FUS::ERG, EWSR1::FLI1, EWSR1::ERG, and a novel FUS::ETV5. Methylation profiling (4 cases) showed all to cluster with previously reported superficial neurocristic EWSR1::FLI1 fusion tumors and apart from conventional and “adamantinoma-like” Ewing sarcoma.Our findings confirm the distinctive clinicopathological features of this very rare, recently described entity and expand its molecular genetic spectrum. Reflecting these findings, we propose modifying the name of this entity to “superficial neurocristic FET::ETS fusion tumor”.

Pediatric Mesenchymal Tumor With MN1::TAF3 Fusion.

MN1 fusion is emerging as oncogenic in soft-tissue tumors. Here, we provided detailed clinicopathological documentation of a tumor with MN1::TAF3 fusion. The tumor developed on the face of an 8-year-old boy and did not recur or metastasize for 5 years after surgery without adjuvant therapy. Histologically, the tumor predominantly comprised sheets and nests of atypical, mildly pleomorphic epithelioid cells. Mallory body-like eosinophilic cytoplasmic inclusions, small round cells, and fascicles of spindle cells were focally observed. Mitotic activity was high, and focal necrosis was present. Immunohistochemically, the tumor was positive for cytokeratin AE1/AE3 in the epithelioid cell component but otherwise showed nonspecific phenotypes. Targeted RNA sequencing identified an in-frame MN1 (exon 1)::TAF3 (exon 3) fusion transcript. We validated the transcript with reverse transcription-polymerase chain reaction, Sanger sequencing, and MN1 break-apart fluorescence insitu hybridization. MN1::TAF3 was previously listed without details in a large-scale sequencing study involving a pediatric round cell sarcoma in the orbit, raising the possibility that these tumors might form a coherent group.

From the archives of MD Anderson Cancer Center. EBV-positive fibrin-associated large B-cell lymphoma in an ovarian leiomyoma with cystic degeneration: A case report and discussion of differential diagnosis

Fibrin-associated large B-cell lymphoma (FA-LBCL) is a rare type of lymphoma usually associated with Epstein-Barr virus (EBV) infection. We report a case incidentally detected in a right ovarian mass of a 53-year-old woman. The patient presented with bloating and weight gain over 8 months. Imaging studies showed a 20.7 cm, complex right adnexal mass. Total abdominal hysterectomy and bilateral salpingo-oophorectomy were performed. Macroscopic examination revealed a 25 × 18.5 × 9.5 cm predominantly cystic right ovarian mass with focal solid areas. Microscopically, most of the mass was a leiomyoma with hyaline necrosis and extensive cystic degeneration. In areas, the cyst showed focally necrotic, fibrinous material associated with small aggregates of round and atypical lymphoid cells with prominent karyorrhexis and mitotic activity These large cells were confined within the cystic spaces. Immunohistochemical analysis showed that the atypical cells were positive for CD20, CD30, CD79a and MUM1/IRF4, and were negative for CD3, CD10 and BCL6 supporting B-cell lineage. In situ hybridization for Epstein-Barr virus-encoded RNA (EBER ISH) was also positive in the atypical cells supporting the diagnosis of EBV-positive fibrin-associated large B-cell lymphoma. The patient subsequently received four cycles of chemotherapy using rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP). Computed tomography (CT) scan of the neck, chest, abdomen and pelvis 5 months after the last chemotherapy cycle showed no evidence of disease. After a follow-up of 37 months, the patient is alive with no evidence of disease. This report is being used to discuss the salient features of this rare entity and its differential diagnosis.

The Role of the Swollen State in Cell Proliferation.

Cell swelling is known to be involved in various stages of the growth of plant cells and microorganisms but in mammalian cells how crucial a swollen state is for determining the fate of the cellular proliferation remains unclear. Recent evidence has increased our understanding of how the loss of the cell surface interactions with the extracellular matrix at early mitosis decreases the membrane tension triggering curvature changes in the plasma membrane and the activation of the sodium/hydrogen (Na +/H +) exchanger (NHE1) that drives osmotic swelling. Such a swollen state is temporary, but it is critical to alter essential membrane biophysical parameters that are required to activate Ca2 + channels and modulate the opening of K + channels involved in setting the membrane potential. A decreased membrane potential across the mitotic cell membrane enhances the clustering of Ras proteins involved in the Ca2 + and cytoskeleton-driven events that lead to cell rounding. Changes in the external mechanical and osmotic forces also have an impact on the lipid composition of the plasma membrane during mitosis.

Primary Adrenal Neuroblastoma in an Adult: A Rare Case Report

ABSTRACT Neuroblastoma (NB), an embryonal malignancy originating from neural crest cells, is predominantly a pediatric disease, making adult cases exceedingly rare. This case report documents the presentation and diagnostic process of a 23-year-old female diagnosed with adrenal NB, a condition scarcely encountered in adults. The patient presented with abdominal pain and a palpable mass. Imaging through computed tomography scan revealed a large necrotic mass in the left adrenal region. Ultrasound-guided fine-needle aspiration cytology (FNAC) showed round cells with scant cytoplasm and characteristic nuclear features, suggesting a round cell tumor, potentially NB. Surgical excision confirmed the diagnosis of poorly differentiated NB with low mitotic-karyorrhectic index. Adult NB, with an incidence of 1 in 10 million per year, has a notably worse prognosis compared to pediatric cases. The literature lacks consensus on optimal treatment protocols for adult patients, though a multimodal approach including surgery, chemotherapy, and possibly radioactive iodine therapy is often employed. This case underscores the utility of FNAC in preliminary diagnosis and highlights the clinical challenges posed by adult NB, emphasizing the need for more comprehensive studies to develop standardized treatment guidelines.

Role and Efficacy of 18F-FDG PET/CT in Following Up Desmoplastic Small Round Cell Tumor of the Abdomen: A Case Report

Role and Efficacy of 18F-FDG PET/CT in Following Up Desmoplastic Small Round Cell Tumor of the Abdomen: A Case Report

An aggressive gastric CIC-DUX4 sarcoma surgically resected with multivisceral organs: a case report

BackgroundCapicua transcriptional repressor-double homeobox 4 sarcoma (CDS) is a rare and aggressive malignant soft tissue tumor that typically arises within the soft tissues. We report an exceptionally rare case of a gastric CDS successfully resected despite its extensive invasion into surrounding organs.Case presentationA 48-year-old male presented with a progressively enlarging abdominal mass. Upper gastrointestinal endoscopy revealed a large ulcerative tumor on the posterior gastric wall. Biopsy results initially suggested a neuroendocrine cell carcinoma. Contrast-enhanced computed tomography showed a 20 cm tumor protruding from the posterior stomach wall, directly invading the pancreas and colon. We performed a multivisceral resection (stomach, pancreatic tail, spleen, and transverse colon) achieving an R0 resection. Pathological examination of the permanent specimen revealed small round cells with high nuclear-to-cytoplasmic ratios. Immunohistochemical staining confirmed the diagnosis of CDS. The patient recovered well and was discharged on postoperative day 33.ConclusionsThis case report describes the first detailed account of a surgically resected aggressive CDS originating from the stomach.

Molecular characterization and immunopathological investigation of Avian reticuloendotheliosis virus in breeder flocks in Egypt

BackgroundReticuloendotheliosis virus (REV) is an oncogenic immunosuppressive retrovirus that infects different kinds of avian species; posing significant economic losses to the poultry industry worldwide.MethodsIn Egypt, there is an unidentified disease associated with the runting-stunting syndrome with neoplasia, suspected to be REV, that has been continuously monitored in several breeder flocks. To diagnose and analyze REV by cell cultures, enzyme-linked immunosorbent assay (ELISA), histopathological investigation, the polymerase chain reaction (PCR) test, and sequencing analysis, 200 blood samples, and 50 tissue specimens were collected. The current study targets the occurrence and genetic characteristics of a viral neoplastic disease, resembling REV infection, circulating in breeder flocks from 2022 to 2023 in the Ismailia, El-Sharqia, and El-Dakahliya governorates.ResultHere, REV was isolated on chicken embryo fibroblast cell culture; exhibiting cell aggregation, rounding, and cell detachments. Collectively, only 70 serum samples were positive for anti‐REV antibodies with seroprevalence rates of 35% based on the ELISA test. The histopathological observation demonstrated lymphoreticular tumors in the liver, spleen, and other examined organs. The immunohistochemical staining method confirmed the REV-positive signals in all examined organs (liver, kidney, spleen, bursa, ovaries) except for the heart. The PCR assay of the LTR gene assessed 370 base pairs with only 5 positive samples with a percentage of 16.6%. Three positive samples were further sequenced and submitted to the Genbank under accession numbers (PP763709, PP763710, PP763711). Phylogenetic analysis of the REV-LTR gene showed that our three isolates (Sharquia-1-REV, Ismilia-2-REV, Mansoura-3-REV) are REV subtype III which predominantly circulated in breeders in Egypt. These three isolates are highest similar to American, Chinese, and Taiwanese REV reference strains, and other Egyptian strains with nucleotide identity percentages of 100%, 99%, and 99%; respectively, and on the amino acid identity level were with (99–100%), (98%, 99%), (99%, 100%); respectively.ConclusionsThis study established that REV infection was extensively distributed in the breeders and became one of the causes of the clinical outbreaks of tumors, raising awareness of REV as the causative agent of avian oncogenic disease in Egypt.

Phytochemical characterization and biomedical potential of Iris kashmiriana flower extracts: a promising source of natural antioxidants and cytotoxic agents.

Iris kashmiriana belongs to the family Iridaceae and is an important endemic medicinal plant of Kashmir. The current study was designed to determine the phytoconstituents, antioxidant, and cytotoxic potential of ethyl acetate (IRK-ETH) and methanol (IRK-MTH) extracts of Iris kashmiriana flowers. IRK-MTH extract demonstrated maximum radical scavenging activity in DPPH, ABTS, and Superoxide anion radical antioxidant assays with IC50 values of 73.15μg/ml, 79.05μg/ml, and 86.52μg/ml respectively. IRK-ETH and IRK-MTH extracts possessed phenolic (70.9 and 208.5 mgGAE/gdw) and flavonoid (487.7 and 40.55mgRE/gdw) contents respectively. In MTT assay IRK-ETH demonstrated the highest cytotoxicity towards the MCF-7 cell line with a GI50 value of 49.13μg/ml. Phase contrast and fluorescence microscopic studies in MCF-7 cells revealed that IRK-ETH extract caused condensation of chromatin, rounding of cells, and nuclear condensation in cells which shows the apoptotic potential of the extract. GCMS analysis for phytochemical characterization revealed the presence of 9 compounds in both extracts which have been reported to possess antibacterial, cytotoxic, and anti-oxidant activities. HPLC analysis confirmed the presence of different polyphenols in both extracts with IRK-MTH extract having maximum polyphenols like epicatechin, rutin, quercetin, vanillic acid, sinapic acid, caffeic acid, chlorogenic acid and ellagic acid. These findings suggest that the flowers of Iris kashmiriana possess very good antioxidant and cytotoxic potential owing to its rich phytoconstituents.

Pseudomyogenic hemangioendothelioma presenting as a penile lesion.

Pseudomyogenic hemangioendothelioma (PHE) is a rare, usually multifocal neoplasm typically affecting individuals in the second-to-fourth decade of life, with a male predominance. It often arises in the distal extremities and characteristically involves multiple tissue planes. Presentation of this neoplasm as a primary penile lesion is exceedingly rare, with only five cases previously documented in the literature. We report the clinicopathologic features of five additional PHEs presenting as primary penile tumors and review previously published cases. Tumors affected young to middle-aged adult patients and had a relatively bland clinical appearance, mimicking indolent lesions such as epidermal inclusion cysts. Microscopically, they were ill-defined nodules composed of plump spindle cells and round neoplastic cells with abundant, densely eosinophilic cytoplasm and eccentric nuclei resembling rhabdomyoblasts. Neoplastic cells demonstrated infiltrative growth, including foci of perineural invasion. Immunohistochemistry demonstrated invariable co-expression of keratins, endothelial markers (CD31 and/or ERG), and FOSB. In conclusion, penile PHE is rare but should be considered in the differential diagnosis of penile lesions with spindle cell and/or rhabdomyoblast-like morphology affecting young to middle-aged adult patients.

Seasonal patterns of neurogenesis in European starlings (Sturnus vulgaris) are region- and sex-specific.

Songbird vocal behavior, physiology, and brains-including neurogenesis-change between seasons. We examined seasonal differences in neurogenesis in three brain regions associated with vocal production and learning, HVC (letter-based proper name), robust nucleus of the arcopallium (RA), and Area X, and two brain regions associated with auditory perception, caudomedial nidopallium (NCM) and caudomedial mesopallium (CMM). To do this, we captured wild male and female European starlings (Sturnus vulgaris) in spring and fall, collected a blood sample, and minimized time from capture to tissue collection to limit suppressive effects of captivity on neurogenesis. We quantified neurogenesis using doublecortin (DCX) immunohistochemistry, counting new neurons of three DCX cell morphologies (multipolar, fusiform, and round). We found regional differences in types of morphologies expressed, and amount of neurogenesis across regions: NCM had more fusiform cells than all other regions, and RA had more round cells than other regions. Males had more neurogenesis in HVC in fall than in spring, but there was no seasonal difference in neurogenesis in HVC of females, perhaps reflecting sexually dimorphic vocal learning demands related to repertoire size and complexity. Plasma corticosterone was higher in spring than fall and was correlated with testis volume in males, but it was not correlated with another purported measure of stress, heterophil:lymphocyteratio (HLR), nor with neurogenesis. Our results suggest that the addition of new neurons to specific regions and circuits may serve different functions for males and females, particularly in the context of vocal production, learning, and perceptual demands across seasons.

Replication Stress is an Actionable Genetic Vulnerability in Desmoplastic Small Round Cell Tumors.

Desmoplastic small round cell tumor (DSRCT) is an aggressive sarcoma subtype that is driven by the EWS-WT1 chimeric transcription factor. The prognosis for DSRCT is poor, and major advances in treating DSCRT have not occurred for over two decades. To identify effective therapeutic approaches to target DSRCT, we conducted a high-throughput drug sensitivity screen in a DSRCT cell line assessing chemosensitivity profiles for 79 small-molecule inhibitors. DSRCT cells were sensitive to PARP and ATR inhibitors (PARPi, ATRi), as monotherapies and in combination. These effects were recapitulated using multiple clinical PARPi and ATRi in three biologically distinct, clinically-relevant models of DSRCT, including cell lines, a patient-derived xenograft (PDX)-derived organoid model, and a cell line-derived xenograft mouse model. Mechanistically, exposure to a combination of PARPi and ATRi caused increased DNA damage, G2/M checkpoint activation, micronuclei accumulation, replication stress, and R-loop formation. EWS-WT1 silencing abrogated these phenotypes and was epistatic with exogenous expression of the R-loop resolution enzyme RNase H1 in reversing the sensitivity to PARPi and ATRi monotherapies. The combination of PARPi and ATRi also induced EWS-WT1-dependent cell-autonomous activation of the cGAS/STING innate immune pathway and cell surface expression of PD-L1. Taken together, these findings point towards a role for EWS-WT1 in generating R-loop-dependent replication stress that leads to a targetable vulnerability, providing a rationale for the clinical assessment of PARPi and ATRi in DSRCT.