Background: Sarcoma may show similarities to malignant melanoma in terms of morphologic and immunohistochemical aspects, hence making it difficult to differentiate between these two neoplasms during the diagnostic process. This systematic review aims to summarize available evidence on cases of sarcoma that were initially diagnosed as melanoma. Methods: A comprehensive search was conducted including MEDLINE/Pubmed, EMBASE and SCOPUS through March 2023. We included case series and case reports of sarcoma patients that were initially diagnosed as malignant melanoma. PRISMA guidelines were followed. Results: Twenty-three case reports and four case series with a total of 34 patients were included. The clinical presentation was heterogeneous, and the most involved anatomical regions were lower limbs (24%), head/neck (24%) and upper limbs (21%). IHC positivity was reported for S100 (69%), HMB45 (63%), MelanA (31%) and MiTF (3%). The main reasons for second assessment were unusual presentation (48%) and uncertain diagnosis (28%). EWSR1 translocation was investigated in 17/34 patients (50%) and found positive in 16/17 (94%). The final diagnosis was clear cell sarcoma (50%) or other soft tissue sarcomas (50%). Conclusions: Melanoma and some histotypes of sarcoma share many similarities. In case of atypical lesions, a second diagnosis should be considered, and ESWR1 translocation should be investigated.

Background: Myeloid sarcoma (MS), also known as granulocytic sarcoma or chloroma, is a rare disease entity characterized by the emergence of an extramedullary tumour which may be antecedent, coexisting or manifest secondarily to an ongoing malignancy of lymphoid origin. Owing to its low prevalence, scientific reports addressing this matter comprise mainly retrospective studies with a limited number of participants, rather low-quality research and only few case reports. Despite MS’s rarity, the need for enhancing diagnostic tools and refinement of therapeutic regimens is broadly recognised among physicians. Case summary: In this case series, we present the clinical histories of two patients diagnosed with MS. The former (Case 1) exhibited MS of the sternum alongside chronic myeloid leukemia (CML), while in case of the latter (Case 2) MS was the initial manifestation of a current acute myeloid leukemia (AML). Regardless of treatment institution comprising chemotherapy (CHTH) and radiotherapy (RT), the patient afflicted by CML did eventually pass due to cardiorespiratory insufficiency secondary to an infection, whereas the second one is in clinical remission up to this date, that is 16 months since MS had been diagnosed. Furthermore, a comprehensive analysis of previously reported cases was conducted which involves MS in patients with AML and CML. Conclusion: The objective of this report is to emphasize the heterogeneity among the clinical manifestations of MS, to underline the relevance of histopathological and molecular diagnostic tools in opting for the appropriate therapy and that, in spite of it occurring rather uncommonly, physicians should think of MS in presence of pathological masses in patients under risk of hematological malignancies.

Introduction: Soft tissue sarcomas (STS) are low-incidence tumors whose clinical and histopathological factors are associated with adverse oncological outcomes. This study evaluated prognostic factors (PF) associated with tumor recurrence and overall survival (OS) in patients diagnosed with STS of the extremities, treated at the Instituto Nacional de Cancerología (INC), Bogotá, Colombia. Materials and methods: An analytical observational study of a historical cohort was carried out, including patients diagnosed with STS and managed surgically in the Functional Unit for Breast and Soft Tissue Tumors of the INC from January 2008 to December 2018. Results: A total of 227 patients were included; 74.5% had tumors greater than 5 cm. Most patients (29.1%) were in stage IIIB at diagnosis. Age was associated with higher mortality (HR=1.01; CI95%: 1–1.02; p=0.048); tumor persistence at admission to the INC (HR=2.34; CI95%: 1.25–4.35; p=0.007), and histologic grade III (HR=5.36; CI95%: 2.29–12.56; p=<0.001) showed statistical significance in the multivariate analysis for recurrence of any type, as were the PFs associated with a higher risk of local recurrence (HR=2.85; CI95%: 1.23–6.57; p=0.014 and HR=6.09; CI95%: 2.03–18.2; p=0.001), respectively. Tumor size (HR=1.03; CI95%: 1–1.06; p=0.015) and histologic grade III (HR=4.53; CI95%: 1.42–14.49; p=0.011) were associated with a higher risk of distant recurrence. Conclusion: This cohort showed that in addition to histologic grade and tumor size, tumor persistence at the time of admission has an impact on disease recurrence, so STS should be managed by a multidisciplinary team with experience in this pathology in high-volume reference centers.

Abstract: High-dose-rate interstitial brachytherapy (HDR-ISBT) has recently come to be considered one of the most effective treatments for oral cancer. On the other hand, it is important to note that radiation therapy has some side effects. Especially, radiation-induced malignancy is probably the most serious complication affecting long-term survivors. We report a case of a radiation-induced undifferentiated spindle cell sarcoma that developed following HDR-ISBT for tongue squamous cell carcinoma (SCC). A 39-year-old woman with right tongue SCC underwent HDR-ISBT (60 Gy, 10 fractions, 8 days) treatment. Five years and one month later, a tumor had developed at the primary site. Surgery was performed for the tumor, which was histopathologically diagnosed as an undifferentiated spindle cell sarcoma. That was distinct from the squamous cell origin of the primary cancer. According to recently established criteria for radiation-induced malignancy, this case was classified as a radiation-induced sarcoma. A search of the literature revealed no previous report of radiation-induced malignancy following HDR-ISBT for tongue cancer.

Purpose: To meet the challenges of the precision medicine era, quality assessment of shared sarcoma care becomes pivotal. The MDT approach is the most important parameter for succesfull outcome. Because of all MDTs disciplines surgery is the key step to render sarcoma patients disease free, defining the spectrum of a sarcoma surgeon is critical. To the best of the authors knowledge, a comprehensive interoperable digital platform to assess the scope of sarcoma surgery and the experience of a sarcoma surgeon in its full complexity is lacking. Methods: A web-based real-world data (RWD) registry on sarcoma surgery has been created to assess the clinical exposure, tumor characteristics, and surgical settings and techniques applied for both resections and reconstructions of sarcomas and thereby the surgical exposure of an individual surgeon over time. Results: During 10 years, there were 723 sarcoma board/MDT meetings discussing 3130 patients. A total of 1094 patients underwent 1250 surgical interventions on mesenchymal tumors by one single sarcoma surgeon. These included 615 deep soft tissue tumors (197 benign, 102 intermediate, 281 malignant, 27 simulator, 7 metastasis, 1 blood), 116 superficial soft tissue tumors (45 benign, 12 intermediate, 40 malignant, 18 simulator, 1 blood) and 519 bone tumors (129 benign, 112 intermediate, 182 malignant, 18 simulator, 46 metastasis, 14 blood and 18 sequelae of 1st treatment). Detailed types of resections and reconstructions were analyzed. Conclusion: A web-based RWD sarcoma surgeon registry with transparent real-time descriptive analytics is feasible and enables large scale definition of the surgical complexity and ultimately quality of sarcoma care.

Kaposi sarcoma is the most common neoplasm associated with Human Immunodeficiency Virus (HIV) infection. Most patients with a confirmed diagnosis experienced limited disease progression. We describe the case of a 49-year-old African American male with a rare presentation of disseminated Kaposi sarcoma as determined by multi-organ work-up. The patient’s cutaneous manifestations involved several hyperpigmented skin lesions, but the worsening of his respiratory symptoms coupled with unexplained weight loss led providers to develop a high suspicion for disseminated disease progression. This case highlights the need to increase awareness of atypical Kaposi sarcoma presentation.

Synovial sarcomas are rare soft tissue tumors that infrequently occur in the ethmoid sinus, posing diagnostic challenges. Herein, we report a case of a 38-year-old male with a 7-month history of recurrent throbbing headaches, left eye pain, and facial nerve palsy, evolving into multiple stroke episodes. Radiological studies showed extension to the cavernous sinus, raising an initial suspicion of vasculitis. Histological findings of an endoscopic biopsy, however, confirmed a monophasic synovial sarcoma. Consequently, the patient was referred to a specialized center for comprehensive management. This case underscores the rarity of ethmoid sinus synovial sarcomas, their diverse clinical presentations, and the necessity of a multidisciplinary approach for accurate diagnosis and tailored therapeutic strategies.

In a single-center, retrospective study, 22 cases were enrolled and divided into two groups: those who underwent surgical wide excision (group A) and those who did not (group B). The study included 13 cases in group A and 9 cases in group B. In group A, 6 cases solely underwent surgical wide excision, while 7 cases received additional treatments like radiotherapy or chemotherapy. Conversely, in group B, 4 cases received chemotherapy, 4 cases received radiotherapy, and 1 case was managed through observation alone. The mean follow-up time was 60.15 months in group A and 43.44 months in group B, with no significant difference observed. In group A, 9 cases resulted in mortality, whereas 6 cases died within the follow-up period in group B. Lesion-free intervals post-operation were observed predominantly in group A, while 7 cases in group B never experienced freedom from skin lesions. Kaplan-Meier survival curve analysis demonstrated a significant difference between the survival curves of the two groups (P = 0.046). Among non-HIV Kaposi’s sarcoma patients, surgical wide excision appears to have a role in treatment. Patients in group A exhibit a more favorable outcome in the survival curve analysis.

Alveolar soft part sarcoma (ASPS) is a rare mesenchymal neoplasm. It affects young adults more and occurs more frequently in the extremities. ASPS is exceedingly rare in the nasal cavity. We report a case of ASPS in the nasal cavity of a 17-year-old female. Its most striking features included organoid and pseudoalveolar arrangement of tumor cells, which were large and polygonal, with vesicular nuclei and abundant eosinophilic cytoplasm rich in granules. There were PAS-positive, diastase-resistant crystalline rods within the cytoplasm. Our case displayed inapparent pseudoalveolar growth pattern and frank pleomorphism. The diagnosis of ASPS, which presents uncommon morphologic findings in unusual sites, is challenging. Recognition of ASPS is greatly assisted by attention to its characteristic cytological features, including intracytoplasmic crystals and immunohistochemistry showing absence of skeletal muscle, epithelial, and neuroendocrine markers.

Malignant peripheral nerve sheath tumors (MPNSTs) are deadly sarcomas that desperately need effective therapies. Half of all MPNSTs arise in patients with Neurofibromatosis Type I (NF1), a common inherited disease. NF1 patients can develop benign lesions called Plexiform Neurofibromas (PNFs), often in adolescence, and over time some PNFs, but not all, will transform into MPNSTs. A deeper understanding of the molecular and genetic alterations driving PNF-MPNST transformation will guide development of more targeted and effective treatments for these patients. This review focuses on an oncogenic transcription factor, FOXM1, that is a powerful oncogene in other cancers but little studied in MPNSTs. Elevated expression of FOXM1 was seen in patient MPNSTs and correlated with poor survival, but otherwise its role in the disease is unknown. We discuss what is known about FOXM1 in MPNSTs relative to other cancers and how FOXM1 may be regulated by and/or regulate the most commonly altered players in MPNSTs, particularly in the MEK and CDK4/6 kinase pathways. We conclude by considering FOXM1, MEK, and CDK4/6 as new, clinically relevant targets for MPNST therapy.

The reconstructive ladder is a well-established concept in Plastic Surgery proposed to achieve wound closure using a stepladder approach from simple to complex procedures and it continues to evolve from when it was presented for the first time. We describe a new surgical technique that allows skin excision and primary wound closure avoiding donor site morbidity from skin grafts and avoiding large scars from loco-regional flaps: the parallelogram excision technique. Fifteen patients with skin lesions underwent this procedure. Six months' follow-up results showed a) good scar healing, b) total excision of lesions, and c) patient acceptance and satisfaction from the usage of this technique. We conducted a geometrical analysis of the parallelogram’s design to study the optimal geometrical condition to achieve all these three factors. We propose that the parallelogram excision of skin lesions proves to be a unique new wound closure technique that may add a new rung to the reconstructive ladder.

We present a case of neglected atypical high grade prostatic stromal sarcoma (PSS) at the transitional zone , invading the peripheral zone, prostatic capsule & peri prostatic fat reaching to pelvic side wall, it showed T2WI hyperintense signal (compared to typical cases of PSS showing T2WI hypointense signal) corresponding to developing on top of pre-existing nodular hyperplasia. Careful reviewing of prostatic central / transitional zone lesions is mandatory especially at T2WI, diffusion & contrast images to exclude malignancy which can be easily missed due to multiple signal patterns described. Most common tumors at transitional zone is stromal sarcoma which could be typical showing T2 hypointense signal or atypical showing T2 hyperintense signal intensity.

Background: Primary cardiac sarcomas (PCS) are extremely rare malignant tumors involving the heart. Only isolated case reports have been described. There is a paucity of data on the epidemiological characteristics of PCS. This study has the objective of investigating the epidemiologic characteristics, survival outcomes, and independent prognostic factors of PCS. Methods: We enrolled a total of 362 patients with PCS, between 2000 and 2017, by retrieving the Surveillance, Epidemiology, and End Results (SEER) database. We analyzed demographics, clinical characteristics, and overall mortality (OM) as well as cancer-specific mortality (CSM) of PCS. Variables with a p-value < 0.1 in the univariate Cox regression were incorporated into the multivariate Cox model to determine the independent prognostic factors, with a hazard ratio (HR) of greater than 1 representing adverse prognostic factors. Results: Crude analysis revealed a high OM in age 80+ (HR=5.958, 95% CI 3.357-10.575, p=0), followed by age 60-79 (HR=1.429, 95% CI 1.028-1.986, p=0.033); and PCS with distant metastases (HR=1.888, 95% CI 1.389-2.566, p=0). Patients that underwent surgical resection of the primary tumor and patients with malignant fibrous histiocytomas (HR=0.657, 95% CI 0.455-0.95, p=0.025) had a better OM (HR=0.606, 95% CI 0.465-0.791, p=0). The highest cancer-specific mortality was observed in age 80+ (HR=5.037, 95% CI 2.606-9.736, p=0) and patients with distant metastases (HR=1.953, 95% CI 1.396-2.733, p=0). Patients with malignant fibrous histiocytomas (HR=0.572, 95% CI 0.378-0.865, p=0.008) and those who underwent surgery (HR=0.581, 95% CI 0.436-0.774, p=0) had a lower CSM. Multivariate Cox proportional hazard regression analyses revealed higher OM in the age group 80+ (HR=13.261, 95% CI 5.839-30.119, p=0) and advanced disease with distant metastases (HR=2.013, 95% CI 1.355-2.99, p=0.001). Lower OM was found in patients with rhabdomyosarcoma (HR=0.364, 95% CI 0.154-0.86, p=0.021) and widowed patients (HR=0.506, 95% CI 0.263-0.977, p=0.042). Multivariate Cox proportional hazard regression analyses of CSM also revealed higher mortality in the same groups, and lower mortality in patients with Rhabdomyosarcoma. Conclusion: In this United States population-based retrospective cohort study using the SEER database, we found that cardiac rhabdomyosarcoma was associated with the lowest CSM and OM. Furthermore, as expected, age and advanced disease at diagnosis were independent factors predicting poor prognosis. Surgical resection of the primary tumor showed lower CSM and OM in the crude analysis but when adjusted for covariates in the multivariate analysis, it did not significantly impact the overall mortality or the cancer-specific mortality. These findings allow for treating clinicians to recognize patients that should be referred to palliative/hospice care at the time of diagnosis and avoid any surgical interventions as they did not show any differences in mortality. Surgical resection in patients with poor prognoses should be reserved as a palliative measure rather than an attempt to cure the disease.

Nanodiamonds of detonation origin are promising delivery agents of anti-cancer therapeutic compounds in a whole organism like mouse, owing to their versatile surface chemistry and ultra-small 5 nm average primary size compatible with natural elimination routes. However, to date, little is known about tissue distribution, elimination pathways and efficacy of nanodiamonds-based therapy in mice. In this report, we studied the capacity of cationic hydrogenated detonation nanodiamonds to carry active small interfering RNA (siRNA) in a mice model of Ewing sarcoma, a bone cancer of young adult due in the vast majority to the EWS-Fli1 junction oncogene. Replacing hydrogen gas by its radioactive analog tritium gas led to the formation of labeled nanodiamonds and allowed us to investigate their distribution throughout mouse organs and their excretion in urine and feces. We also demonstrated that siRNA directed against EWS-Fli1 inhibited this oncogene expression in tumor xenografted on mice. This work is a significant step to establish cationic hydrogenated detonation nanodiamond as an effective agent for in vivo delivery of active siRNA.

Introduction: A dual malignancy with both Ewing Sarcoma and Prostate Adenocarcinoma has not been reported in the English literature. We report a case of simultaneous diagnosis of Ewing sarcoma and prostate adenocarcinoma with profound clinical manifestation. Case presentation: A 53-year-old male with advanced metastatic prostate cancer (Gleason-9) admitted with classical presentation of cauda equina syndrome including incontinence, back pain, and paresis following bilateral nephrostomy insertion for the treatment of bilateral renal hy-dronephrosis. The patient was diagnosed with an epidural abscess at the level of L5-S1 and an emergency surgical spine decompression was performed. No abscess was found, and pathology results showed a concomitant primary Ewing sarcoma in the spine. Conclusions: Very rare occurrences of a dual primary malignancy, in this case, Ewing sarcoma and prostate adenocarcinoma, should be kept in mind in patients suffering from complex clinical course of malignancies.

Management of sarcomas in specialist centers delivers significant benefits. In much of the world specialists are not available and development of expertise is identified as a major need. However the terms ‘specialist’ or ‘expert’ center are rarely defined. Our objective is to offer a definition for patient advocates and a tool for healthcare providers to underpin improving the care of people with sarcoma. SPAGN developed a discussion paper for a workshop at the SPAGN 2023 Conference, attended by 75 delegates. A presentation to the Connective Tissue Oncology Society (CTOS) and further discussion led to this paper. Core Principles were identified that underlie specialist sarcoma care. The primary principle is the multi-disciplinary team discussing every patient, at first diagnosis and during treatment. Principles for optimal sarcoma management include accurate diagnosis followed by safe, high-quality treatment, with curative intent. These Principles are supplemented by Features describing areas of healthcare, professional involvement, and service provision and identifying further research and development needs. These allow for variations because of national or local policies and budgets. We propose the term ‘Sarcoma Intelligent Specialist Network’ to recognize expertise wherever it is found in the world. This provides a base for further discussion and local refinement.

Introduction: This study aimed to evaluate whether radiomic features extracted solely from the edema of soft tissue sarcomas (STS) could predict the occurrence of lung metastasis in comparison with features extracted solely from the tumoral mass. Materials and Methods: We retrospectively analyzed magnetic resonance imaging (MRI) scans of 32 STSs including 14 with lung metastasis and 18 without. Segmentation of the tumor mass and edema was performed for each MRI examination. A total of 107 radiomic features were extracted for each mass segmentation and 107 radiomic features for each edema segmentation. A two-step feature selection process was applied. Two predictive features for the development of lung metastasis were selected from the mass-related features, as well as two predictive features from the edema-related features. Two random forest models were created based on these selected features; 100 random subsampling runs were performed. Key performance metrics including accuracy and area under the ROC curve (AUC) were calculated, and the resulting accuracies were compared. Results: The model based on mass-related features achieved a median accuracy of 0.83 and a median AUC of 0.88, while the model based on edema-related features achieved a median accuracy of 0.75 and a median AUC of 0.79. Statistical analysis comparing the accuracies of the two models revealed no significant difference. Conclusion: Both models showed promise in predicting the occurrence of lung metastasis in soft tissue sarcomas. These findings suggest that radiomic analysis of edema features can provide valuable insights into the prediction of lung metastasis in soft tissue sarcomas.

Kaposi’s sarcoma-associated herpesvirus (KSHV), also known as human herpesvirus-8, is the causative agent of Kaposi’s sarcoma, Castleman’s disease, and primary effusion lymphoma. Although the functions of the viral thymidine kinases (vTK) of herpes simplex virus-1/2 and varicella zoster virus are well understood, that of KSHV ORF21 (an ortholog of vTK) is largely unknown. Here, we investigated the role of ORF21 in lytic replication and infection by generating two ORF21-mutated KSHV BAC clones: ORF21-kinase activity deficient-KSHV (21KD) and stop codon-induced ORF21-deleted-KSHV (21del). The results showed that both ORF21-mutations did not affect viral genome replication, lytic genes transcription, or the production of viral genome-encapsidated particles. ORF21 molecule-dependent function, other than the kinase function of ORF21, was involved in the infectivity of progeny virus. ORF21 was expressed at 36 h after induction of lytic replication, and endogenously expressed ORF21 was localized in the whole cytoplasm and decreased on the cell surface area. Moreover, the effects of ORF21 expression on signaling pathways and proliferation were analyzed. The results showed that ORF21 upregulated the MEK phosphorylation and anchorage-independent cell growth. These findings indicate that ORF21 plays key roles in both infection and oncogenesis of KSHV through the manipulation of cellular function.

Several types of soft tissue sarcomas have peripheral infiltrative growth characteristics called tail-like lesions. The efficacy of neoadjuvant therapy for tumors with tail-like lesions has not been elucidated. From 2012 to 2019, we analyzed 36 patients with soft tissue sarcoma with tail-like lesions treated with neoadjuvant therapy, including chemotherapy, radiotherapy, or both. The ef-fect of neoadjuvant therapy on the tail sign was investigated by analyzing the change in tail-like lesions during neoadjuvant therapy and histological responses. The median length of the tail-like lesion reduced from 29.5 mm at initiation to 19.5 mm after neoadjuvant therapy. The extent of shrinkage in tail-like lesion was related to the histopathological responses in the main part. Com-plete disappearance of the tail-like lesion was observed in 12 patients; however, it was not related to achieving a microscopically negative margin. The oncologic outcomes did not significantly differ between cases with complete disappearance of tail-like lesions or not. This study indicated the shrinkage of tail-like lesions did not have significant effect on complete resection or improve-ment of clinical outcomes. A more comprehensive evaluation is needed to elaborate on the surgi-cal strategy.

Electrochemotherapy (ECT) is one of the newest therapeutic strategies employed as medical procedure for skin neoplasms’ treatment, especially for Classic Kaposi’s Sarcoma (CKS). The aim of this study was to demonstrate ECT clinical response and local control of CKS disease. Primary endpoint was to value the worth and efficacy of this local therapy in CKS skin lesions’ treatment. Nineteen CKS patients were enrolled, 14 males and 5 females with median age at diagnosis of 72. Complete response (CR) has been gained in 12 patients after first ECT attempt, meanwhile 3 and 4 out of 19 patients obtained a Partial response (PR), so that they underwent to a second and a third ECT treatment, each other. Clinical response was evaluated during all the time of the follow-up, which ranged between 3 months and 4 years with a median of 18 months. CKS skin lesions control still represents a challenge for surgeons and oncologists. Nevertheless, according to this and other authors’ recent experiences, ECT could be considered the gold standard strategy for early-stage patients, but at the same time it could be considered as a valid option in controlling Kaposi’s Sarcoma locally advanced lesions.

The Sarcoma Assessment Measure (SAM) was developed as a sarcoma-specific patient-reported outcome measure to be used in clinical practice. We have reported in detail how SAM has been developed in collaboration with patients and healthcare professionals. The aim of this paper is to report the preliminary validation of SAM. The 22-item SAM was administered alongside a validated quality of life questionnaire and measure of activities of daily living. Linear modelling was used to build a measure, which had predictive validity in comparison to more established outcome measures. Of the 762 patients who participated in the study, 44.1% identified as male, and participant age ranged from 13-82 years. Clinically, participants presented with a range of soft tissue (82.2%) and bone (21.8%) sarcomas. Our preliminary analysis indicates that SAM accounts for 35% of the Global quality of life scale and 18% of the TESS so psychometrically it overlaps with quality of life and activities of daily living, but also measures distinct concerns. This demonstrates that this measure picks up issues that are important to patients with sarcoma that are not reflected in other measures. We have established the preliminary validity of SAM and believe it has utility as a patient-reported outcome measure both as a research tool and for assessing the impact of symptoms and dysfunction related to sarcoma as part of clinical care. Further validation using a larger and more clinically diverse sample is now needed.

Epigenetic reprogramming represents a series of essential events during many cellular processes including oncogenesis. Genome of Kaposi’s sarcoma-associated herpesvirus (KSHV), an oncogenic herpesvirus is predetermined for a well-orchestrated epigenetic reprogramming once it enters into a host cell. The initial epigenetic reprogramming of KSHV genome allow restricted expression of encoded genes and helps to hide from host immune recognition. The infection with KSHV is associated with Kaposi's Sarcoma, Multicentric Castleman's disease, KSHV inflammatory cytokine syndrome and primary effusion lymphoma. The major epigenetic modifications associated with KSHV can be labelled under three broad categories: DNA methylation, modifications of Histone, and the role of noncoding RNAs. These epigenetic modifications significantly contribute towards the latent-lytic switch of the KSHV lifecycle. This review gives a brief account of the major epigenetic modifications affiliated with the KSHV genome in infected cells and their impact on pathogenesis.

Ewing sarcoma (EWS) is an aggressive pediatric malignancy of the bone and soft tissues in need of novel therapeutic options. To identify potential therapeutic targets, we focused on essential biological pathways that are upregulated by EWS-FLI1, the primary oncogenic driver of EWS, including mitotic proteins such as Aurora Kinase A (AURKA), Kinesin Family Member 15 (KIF15) and its binding partner, targeting protein for Xklp2 (TPX2). KIF15/TPX2 cooperates with KIF11, a key mitotic kinesin essential for mitotic spindle orientation. Given the lack of clinical grade KIF15/TPX2 inhibitors, we chose to target KIF11 (using SB-743921) in combination with AURKA (using VIC-1911), given phosphorylation of KIF15S1169 by Aurora A is required for its targeting to the spindle. In vitro, the drug combination demonstrated strong synergy (Bliss score ≥10) at nanomolar doses. Colony formation assay revealed significant reduction in plating efficiency (1-3%) and increased percent accumulation of cells in G2/M phase with the combination treatment (45-52%) upon cell-cycle analysis indicating mitotic arrest. In vivo studies in EWS xenograft mouse models showed significant tumor reduction and overall effectiveness: drug combination vs vehicle control (p≤0.01), SB-743921 (p≤0.01) and VIC-1911 (p≤0.05). Kaplan-Meier curves demonstrated superior overall survival with the combination compared to vehicle or monotherapy arms (p≤0.0001).

Cancer is the second biggest cause of death in children. With the development of chemotherapy, there is a substantial increase in overall survival rate over recent 30 years. However, the overall mortality rate in children with cancer still remains 25%, and many survivors experience a decline in overall quality of life and long-term adverse effects caused by treatments. Although cancer cells share common characteristics, pediatric cancers are different from adult cancers in their prevalence, mutation load, and drug response. Therefore, there is an urgent unmet need to develop therapeutic approaches specifically designed for children with cancer. Nanotechnology can potentially overcome the deficiencies of conventional methods of administering chemotherapy and ultimately improve clinical outcomes. The nanoparticle-based drug delivery systems can decrease the toxicity of therapy, provide a sustained or controlled drug release, improve pharmacokinetic properties of loading contents, and achieve a targeted drug delivery with achievable modifications. Further, therapeutic approaches based on combining nanoformulated drugs with novel immunotherapeutic agents are emerging. In this review, we discuss the recently developed nanotechnology-based strategies for treating blood and solid pediatric cancers.

Kaposi’s sarcoma associated-herpesvirus (KSHV, also known as human herpesvirus-8) is a gammaherpesvirus that establishes life-long infection in human B lymphocytes. KSHV infection is typically asymptomatic but immunosuppression can predispose KSHV-infected individuals to primary effusion lymphoma (PEL); a malignancy driven by aberrant proliferation of latently infected B lymphocytes, and supported by pro-inflammatory cytokines and angiogenic factors produced by cells that succumb to lytic viral replication. Here, we report the development of the first in vivo model for a virally-induced lymphoma in zebrafish, whereby KSHV-infected PEL tumour cells engraft and proliferate in the yolk sac of zebrafish larvae. Using a PEL cell line engineered to produce the viral lytic switch protein RTA in the presence of doxycycline, we demonstrate drug-inducible reactivation from KSHV latency in vivo, which enabled real-time observation and evaluation of latent and lytic phases of KSHV infection. In addition, we developed a sensitive droplet digital PCR method to monitor latent and lytic viral gene expression and host cell gene expression in xenografts. The zebrafish yolk sac is not well-vascularized and using fluorogenic assays we confirmed that this site provides a hypoxic environment that may mimic the microenvironment of some human tumors. We found that PEL cell proliferation in xenografts was dependent on the host hypoxia-dependent translation initiation factor, eukaryotic initiation factor 4E2 (eIF4E2). This demonstrates that the zebrafish yolk sac is a functionally hypoxic environment and xenografted cells must switch to dedicated hypoxic gene expression machinery to survive and proliferate. The establishment of the PEL xenograft model enables future studies that exploit the innate advantages of the zebrafish as a model for genetic and pharmacologic screens.

Background: PRAME, NY-ESO-1 and SSX2 are cancer testis antigens (CTAs), which in normal tissues are expressed in testicular germ cells with re-expression in numerous cancer types. Their ability to elicit humoral and cellular immune responses have rendered them promising targets for cancer immunotherapy, but they have never been studied in a large and well-characterized cohort soft tissue sarcomas (STS). Methods: On protein level, we examined PRAME, NY-ESO-1 and SSX2 expression in tumour tissues of 249 STS using immunohistochemistry. We correlated expression levels with clinicopathological parameters including Tumour-infiltrating lymphocyte (TIL) counts, grading and long- term survival. Results: Expression of PRAME, NY-ESO-1 and SSX2 was observed in 25 (10%), 19 (8%), and 11 (4%) of 249 specimens with distinct patterns for histo subtypes. Expression of PRAME was associated with shorter patient survival (p=0.005) and higher grade (G2 vs G3, p=0.001) while NY-ESO-1 expression was correlated with more favourable survival (p=0.037) and low grade (G2 vs G3, p=0.029). Both PRAME and NY-ESO-1 expression was more frequent in STS with low TILs counts. Conclusions: CTAs PRAME, NY-ESO-1 and SSX2 show distinct expression patterns in different STS subtypes. These results may guide future immunotherapeutic approaches in STS.

Sarcomas are a heterogenous group of tumours that commonly carry poor prognosis with limited therapeutic options. Adolescents and young adults (AYA) with sarcoma are a unique and under-studied patient population that have only achieved modest survival gains compared to other groups. We present our institutional experience of AYA with sarcoma who underwent comprehensive molecular profiling (CMP) using either large-panel targeted DNA sequencing or whole genome and transcriptome sequencing and evaluated the feasibility and clinical impact of this approach. Genomic variants detected were determined to be clinically relevant and actionable following the Molecular Tumour Board evaluation. Clinicians provided feedback regarding the utility of testing three months after reporting. Twenty-five patients who were recruited for CMP are included in this analysis. The median time from consent to final molecular report was 45 days (interquartile range 37-57). Potentially actionable variants were detected for 14 patients (56%) and new treatment recommendations were identified for 12 patients (48%). Pathogenic germline variants were identified in three patients (12%), and one patient had a change of diagnosis. Implementation for CMP for AYA with sarcoma is clinically valuable, feasible and should be increasingly integrated into routine clinical practice as technologies and turnaround times continue to improve.

Kaposi’s sarcoma-associated herpesvirus (KSHV) is the etiologic agent of Kaposi’s sarcoma, primary effusion lymphoma (PEL) and multicentric Castleman’s disease. During KSHV lytic infection, lytic-related genes, categorized as immediate-early, early, and late genes, are expressed in a temporal manner. The transcription of late genes requires the virus-specific pre-initiation complex (vPIC), which consists of viral transcription factors. However, the characterization of the protein-protein interactions of the vPIC factors has not been completely elucidated. KSHV ORF18 is one of the vPIC factors, and its interaction with other viral factors has not been sufficiently revealed. Here, we analyzed the interaction between ORF18 and another vPIC factor, ORF30, in living cells using the bimolecular fluorescence complementation (BiFC) assay. We identified four amino-acid residues (Leu29, Gln36, His41 and Trp170) on ORF18 that were responsible for its interaction with ORF30. The artificial intelligence (AI) system AlphaFold2 predicted that identified four residues are exposed to the surface of ORF18 and located in proximity to each other in the surface of ORF18. Thus, AI-predicted model supports the importance of four residues for binding of ORF18 to ORF30. Our results indicated that wet experiments in combination with AI may enhance the structural characterization of vPIC protein-protein interactions.

Herpesviruses usurp cellular stress responses to avoid immune detection while simultaneously promoting viral replication and spread. The unfolded protein response (UPR) is an evolutionarily conserved stress response that is activated when the protein load in the ER saturates its chaperone folding capacity causing an accrual of misfolded proteins. Through translational and transcriptional reprogramming, the UPR aims to restore protein homeostasis; however, if this fails the cell undergoes apoptosis. It is commonly thought that many enveloped viruses, including herpesviruses, may activate the UPR due to saturation of the ER with nascent glycoproteins and thus these viruses may have evolved mechanisms to evade the potentially negative effects of UPR signaling. Over the past fifteen years there has been considerable effort to provide evidence that different viruses may reprogram the UPR to promote viral replication. Here we provide an overview of the molecular events of UPR activation, signaling and transcriptional outputs, and highlight key findings that demonstrate that the UPR is an important cellular stress response that herpesviruses have hijacked to facilitate persistent infection.

Human oncoviruses are able to subvert telomerase function in cancer cells through multiple strategies. The activity of the catalytic subunit of telomerase (TERT) is commonly enhanced in virus-related cancers. Viral oncoproteins, such as high-risk human papillomavirus (HPV) E6, Epstein-Barr virus (EBV) LMP1, Kaposi sarcoma-associated herpesvirus (HHV-8) LANA, hepatitis B virus (HBV) HBVx, hepatitis C virus (HCV) core protein and human T-cell leukemia virus-1 (HTLV-1) tax protein, interact with regulatory elements in the infected cells and contribute to the transcriptional activation of TERT gene. Specifically, viral oncoproteins have been shown to bind TERT promoter, to induce post-transcriptional alterations of TERT mRNA and to cause epigenetic modifications, which have important effects on the regulation of telomeric and extra-telomeric functions of the telomerase. Other viruses, such as herpesviruses, operate by integrating their genomes within the telomeres or by inducing alternative lengthening of telomeres (ALT) in non-ALT cells. In this review, we recapitulate recent findings on virus-telomerase/telomeres interplay and the importance of TERT-related oncogenic pathways activated by cancer causing viruses.