Genetic and Epigenetic Characterization of Sarcoma Stem Cells Across Subtypes Identifies EZH2 as a Therapeutic Target.

High-grade complex karyotype soft tissue sarcomas (STS) are a heterogeneous and aggressive set of cancers that share a common treatment strategy. Disease progression and failure to respond to anthracycline based chemotherapy, standard first-line treatment, is associated with poor patient outcomes. To address this, we investigated the contribution of STS cancer stem cells (STS-CSCs) to doxorubicin resistance. We identified a positive correlation between CSC abundance and doxorubicin IC 50 in resistant cell lines. We investigated if a common genetic signature across STS-CSCs could be targeted. Utilizing patient derived samples from five sarcoma subtypes we identified Enhancer of Zeste homolog 2 (EZH2), a member of the polycomb repressive complex 2 (PRC2) responsible for H3K27 methylation as being enriched in the CSC population. EZH2 activity and a shared epigenetic profile was observed across subtypes. Targeting of EZH2 using Tazemetostat, an FDA approved inhibitor specifically ablated the STS-CSC population. Treatment of doxorubicin resistant cell lines with tazemetostat resulted in a decrease in the STS-CSC population. Further, co-treatment was not only synergistic in the parent cell lines, but restored chemosensitivity in doxorubicin resistant lines. These data confirm the presence of shared genetic programs across distinct subtypes of CSC-STS that can be therapeutically targeted.

Emerging innovations and advancements in the treatment of extremity and truncal soft tissue sarcomas.

In this special edition update on soft tissue sarcomas (STS), we cover classifications, emerging technologies, prognostic tools, radiation schemas, and treatment disparities in extremity and truncal STS. We discuss the importance of enhancing local control and reducing complications, including the role of innovative imaging, surgical guidance, and hypofractionated radiation. We review advancements in systemic and immunotherapeutic treatments and introduce disparities seen in this vulnerable population that must be considered to improve overall patient care.

Scrutinizing the use of contrasted chest CTs in extremity sarcoma staging and surveillance.

BACKGROUND: Since 2015, the American College of Radiology (ACR) has recommended staging for lung metastasis via chest computed tomography (CT) without contrast for extremity sarcoma staging and surveillance. The purpose of this study was to determine our institutional compliance with this recommendation. METHODS: This was a retrospective chart review of patients diagnosed with sarcoma in the extremities who received CT imaging of the chest for pulmonary staging and surveillance at our institution from 2005 to 2023. A total of 1916 CT studies were included for analysis. We scrutinized ordering patterns before and after 2015 based on the ACR-published metastasis staging and screening guidelines. An institutional and patient cost analysis was performed between CT modalities. RESULTS: The prevalence of CT scans ordered and performed with contrast was greater than those without contrast both prior and post-ACR 2015 guidelines. Furthermore, 79.2% of patient's final surveillance CTs after 2015 were performed with contrast. A cost analysis was performed and demonstrated an additional $297 704 in patient and institutional costs. CONCLUSIONS: At our institution, upon review of CT chest imaging for pulmonary staging and surveillance in patients with extremity sarcoma the use of contrast has been routinely utilized despite a lack of evidence for its necessity and contrary to ACR guidelines.

Wild-type C-Raf gene dosage and dimerization drive prostate cancer metastasis.

Mutated Ras and Raf kinases are well-known to promote cancer metastasis via flux through the Ras/Raf/MEK/ERK (mitogen-activated protein kinase [MAPK]) pathway. A role for non-mutated Raf in metastasis is also emerging, but the key mechanisms remain unclear. Elevated expression of any of the three wild-type Raf family members (C, A, or B) can drive metastasis. We utilized an in vivo model to show that wild-type C-Raf overexpression can promote metastasis of immortalized prostate cells in a gene dosage-dependent manner. Analysis of the transcriptomic and phosphoproteomic landscape indicated that C-Raf-driven metastasis is accompanied by upregulated MAPK signaling. Use of C-Raf mutants demonstrated that the dimerization domain, but not its kinase activity, is essential for metastasis. Endogenous Raf monomer knockouts revealed that C-Raf's ability to form dimers with endogenous Raf molecules is important for promoting metastasis. These data identify wild-type C-Raf heterodimer signaling as a potential target for treating metastatic disease.

Human soft tissue sarcomas harbor an intratumoral viral microbiome which is linked with natural killer cell infiltrate and prognosis.

BACKGROUND: Groundbreaking studies have linked the gut microbiome with immune homeostasis and antitumor immune responses. Mounting evidence has also demonstrated an intratumoral microbiome, including in soft tissue sarcomas (STS), although detailed characterization of the STS intratumoral microbiome is limited. We sought to characterize the intratumoral microbiome in patients with STS undergoing preoperative radiotherapy and surgery, hypothesizing the presence of a distinct intratumoral microbiome with potentially clinically significant microbial signatures. METHODS: We prospectively obtained tumor and stool samples from adult patients with non-metastatic STS using a strict sterile collection protocol to minimize contamination. Metagenomic classification was used to estimate abundance using genus and species taxonomic levels across all classified organisms, and data were analyzed with respect to clinicopathologic factors. RESULTS: Fifteen patients were enrolled. Most tumors were located at an extremity (67%) and were histologic grade 3 (87%). 40% were well-differentiated/dedifferentiated liposarcoma histology. With a median follow-up of 24 months, 4 (27%) patients developed metastases, and 3 (20%) died. Despite overwhelming human DNA (>99%) intratumorally, we detected a small but consistent proportion of bacterial DNA (0.02-0.03%) in all tumors, including Proteobacteria, Bacteroidetes, and Firmicutes, as well as viral species. In the tumor microenvironment, we observed a strong positive correlation between viral relative abundance and natural killer (NK) infiltration, and higher NK infiltration was associated with superior metastasis-free and overall survival by immunohistochemical, flow cytometry, and multiplex immunofluorescence analyses. CONCLUSIONS: We prospectively demonstrate the presence of a distinct and measurable intratumoral microbiome in patients with STS at multiple time points. Our data suggest that the STS tumor microbiome has prognostic significance with viral relative abundance associated with NK infiltration and oncologic outcome. Additional studies are warranted to further assess the clinical impact of these findings.

Socioeconomic and insurance-related disparities in disease-specific survival among patients with metastatic bone disease.

BACKGROUND: Approximately 5% of cancer patients in the United States presented with metastatic bone disease (MBD) at diagnosis. Current study explores the disparities in survival for patients with MBD. METHODS: Patients with the diagnosis of MBD at presentation for the five most common primary anatomical sites were extracted from Surveillance, Epidemiology, and End Results Census tract-level dataset (2010-2016). Kaplan-Meier and Cox Proportional Hazard models were used to evaluate survival, and prognostic factors for each cohort. Prognostic significance of socioeconomic status (SES) and insurance status were ascertained. RESULTS: The five most common anatomical-sites with MBD at presentation included "lung" (n = 59 739), "prostate" (n = 19 732), "breast" (n = 16 244), "renal and urothelium" (n = 7718) and "colon" (n= 3068). Lower SES was an independent risk factor for worse disease-specific survival (DSS) for patients with MBD originating from lung, prostate, breast and colon. Lack of insurance was an independent risk factor for worse DSS for MBD patients with primary tumors in lung and breast. CONCLUSIONS: MBD patients from the five most common primary sites demonstrated SES and insurance-related disparities in disease-specific survival. This is the first and largest study to explore SES and insurance-related disparities among patients specifically afflicted with MBD. Our findings highlight vulnerability of patients with MBD across multiple primary sites to financial toxicity.

Case report: Treatment of metastatic dedifferentiated chondrosarcoma with pembrolizumab yields sustained complete response.

Dedifferentiated chondrosarcomas (DDCS) are aggressive tumors with poor outcomes. Treatment of localized DDCS is primarily surgical, though most patients present with unresectable or metastatic disease. Systemic treatment options for advanced DDCS are limited, and the benefits of chemotherapy in this patient population remain controversial. Among other systemic therapy options, there is emerging clinical evidence to support the use of immunotherapy in patients with advanced DDCS. However, studies regarding the efficacy of immunotherapy in advanced DDCS are limited. Here, we present the case of a patient with metastatic, programmed death-ligand 1 (PD-L1)-positive DDCS treated with pembrolizumab who showed a sustained complete response for 24 months after initiation of therapy. To our knowledge, this case represents one of few documented cases of metastatic chondrosarcoma with sustained response to immunotherapy. The impressive response seen with PD-L1 inhibition in our patient indicates that immunotherapy is a successful treatment option in a subset of DDCS patients, and further investigation is needed to identify potential responders to immunotherapy.

NCCN Guidelines® Insights: Gastrointestinal Stromal Tumors, Version 2.2022.

Gastrointestinal stromal tumors (GIST) are the most common type of soft tissue sarcoma that occur throughout the gastrointestinal tract. Most of these tumors are caused by oncogenic activating mutations in the KIT or PDGFRA genes. The NCCN Guidelines for GIST provide recommendations for the diagnosis, evaluation, treatment, and follow-up of patients with these tumors. These NCCN Guidelines Insights summarize the panel discussion behind recent important updates to the guidelines, including revised systemic therapy options for unresectable, progressive, or metastatic GIST based on mutational status, and updated recommendations for the management of GIST that develop resistance to specific tyrosine kinase inhibitors.

Head and Neck Cutaneous Soft-Tissue Sarcoma Demonstrate Sex and Racial/Ethnic Disparities in Incidence and Socioeconomic Disparities in Survival.

BACKGROUND: Cutaneous soft-tissue sarcoma (CSTS) of the head and neck are rare and are known to have aggressive clinical course. The current study utilizes a population-based registry in the U.S. to characterize these malignancies and explore disparities. METHODS: National Cancer Institute's (NCI) Surveillance, Epidemiology and End Result (SEER) database from 2000 to 2018 was queried to report incidence and survival data in 4253 cases in the U.S. RESULTS: Males were 5.37 times more likely and Non-Hispanic-White people (NHW) were 4.62 times more likely than females and Non-Hispanic-Black people (NHB) to develop CSTS of the head and neck. The overall incidence was 0.27 per 100,000 persons in 2018, with a significant increase since 2000. Advanced age and stage, histologic group other than 'fibromatous sarcoma' and lower SES groups were independent factors for worse overall survival. CONCLUSIONS: CSTS of the head and neck demonstrate sex and racial/ethnic disparities in incidence and socioeconomic disparities in overall survival. LEVEL OF EVIDENCE: II.

Soft Tissue Sarcoma, Version 2.2022, NCCN Clinical Practice Guidelines in Oncology.

Soft tissue sarcomas (STS) are rare malignancies of mesenchymal cell origin that display a heterogenous mix of clinical and pathologic characteristics. STS can develop from fat, muscle, nerves, blood vessels, and other connective tissues. The evaluation and treatment of patients with STS requires a multidisciplinary team with demonstrated expertise in the management of these tumors. The complete NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines) for Soft Tissue Sarcoma provide recommendations for the diagnosis, evaluation, and treatment of extremity/superficial trunk/head and neck STS, as well as retroperitoneal/intra-abdominal STS, desmoid tumors, and rhabdomyosarcoma. This portion of the NCCN Guidelines discusses general principles for the diagnosis and treatment of retroperitoneal/intra-abdominal STS, outlines treatment recommendations, and reviews the evidence to support the guidelines recommendations.

Impact of local treatment modality on overall- and disease-specific survival for nonmetastatic pelvic and sacral Ewing sarcoma.

PURPOSE: The ideal local treatment modality for pelvic and sacral Ewing sarcoma (EWS) is controversial. METHODS: We present the data from the American College of Surgeon's National Cancer Database (NCDB) and the National Cancer Institute's Surveillance, Epidemiology and End Result (SEER) database to investigate the impact of local treatment modalities on survival for nonmetastatic pelvic and sacral Ewing sarcoma. Local treatment includes "surgery," "radiation," and a combination of "surgery and radiation." RESULTS: A total of 235 cases from SEER and 285 cases from NCDB were analyzed. Patients with "localized" stage (intraosseous) in the SEER database did not show any statistically significant difference in the disease-specific survival (DSS) for any of the local treatment modalities. Similar findings were observed for overall survival among patients with American Joint Committee on Cancer (AJCC) stage II and III in the NCDB database. However, patients with nonmetastatic disease, particularly regional disease (extraosseous), showed improved DSS with surgery only, in the SEER. CONCLUSION: We found similar levels of efficacy for different treatment modalities for patients with intraosseous and AJCC II and III pelvic and sacral EWS. "Radiotherapy" is the most common local treatment modality employed in the United States. A prospective, randomized controlled trial with a direct head-to-head comparison is needed for a definitive conclusion.

Non-Private Health Insurance Predicts Advanced Stage at Presentation and Amputation in Lower Extremity High Grade Bone Sarcoma: A National Cancer Database Study : Amputation Predicts Survival: An Effect Most Pronounced in Pediatric and AYA Age Group.

INTRODUCTION: Advances in diagnostic and treatment modalities for high grade bone sarcomas (HGBS) of lower extremity (LE) have enabled limb salvage resections as a feasible first-line surgical option. However, amputations are still performed. Impact of amputation on survival and predictive factors for amputation and the stage at presentation for HGBS of LE remain unknown. METHODS: National Cancer Database was used to extract 5781 cases of high-grade bone sarcoma of the LE from 2004 to 2017. Kaplan-Meier and Cox regression were used to determine the impact of amputation on survival. Chi square test and logistic regression were used to assess the correlation of predictive factors with amputation and stage at presentation. RESULTS: Amputation [hazard ratio (HR) 1.516; 95% confidence interval (CI) 1.259-1.826; p < 0.001] and advanced stage (HR 0.248; 95% CI 0.176-0.351; p < 0.001) were independent predictors of poor overall survival. The impact of amputation on survival was most pronounced for pediatric and adolescents and young adults (AYA) age groups (18% decrease in 10-year survival). Amputation was more likely to be performed among those with nonprivate insurance (HR 1.736; 95% CI 1.191-2.531; p = 0.004), a finding that was mirrored for advanced stage at presentation (HR 0.611; 95% CI 0.414-0.902; p = 0.013). DISCUSSION: Amputation is an independent predictor of poor outcomes among patients with HGBS of LE. The impact of amputation on survival is the highest for the pediatric and AYA age group. Nonprivate insurance is associated with increased likelihood of amputation and an advanced stage at presentation among patients with high-grade bone sarcoma of the LE. This is the largest study highlighting insurance-related disparities in this cohort.

Sex, racial/ethnic and socioeconomic disparities in patients with metastatic bone disease.

BACKGROUND: We have analyzed sex, race/ethnicity or socioeconomic disparities in the incidence of metastatic bone disease (MBD). METHODS: Patients with the diagnosis of MBD at presentation for five most common primary anatomical sites was extracted from Surveillance, Epidemiology, and End Results Census tract-level dataset. Mean incidence of MBD for different sex, racial/ethnic and socioeconomic groups were compared. RESULTS: The five most common anatomical sites with MBD at presentation include "lung: (n = 59 739), "prostate" (n = 19 732), "breast" (n = 16 244), "renal" (n = 7718) and "colon" (n = 3068). There was an increase in incidence of MBD among cancers originating from prostate (annual percentage change [APC] 4.94), renal (APC 2.55), and colon (APC 3.21) (p < 0.05 for all). Non-Hispanic Blacks had higher incidence of MBD for prostate and breast primary sites (p < 0.001). Non-Hispanic American Indian Alaskan Native had higher incidence of MBD for cancers originating from renal (p < 0.001) and colon (p = 0.049). A higher incidence of MBD was seen in lower socioeconomic status (SES) groups for the selected sites (p < 0.001). CONCLUSIONS: These findings suggest that there are multiple sex-related, racial/ethnic and SES disparities in the incidence of MBD from the 5 most common primary sites. Higher incidence seen among lower SES suggests delay in diagnosis and limited access to screening modalities.

Prognostic factors, disparity, and equity variables impacting prognosis in bone sarcomas of the hand: SEER database review.

BACKGROUND: Primary sarcomas originating from the bones of hand and wrist are rare but carry a significant burden of morbidity. METHODS: National Cancer Institute's Surveillance, Epidemiology and End Result database from 1975 to 2017 was queried to report incidence and survival data in 237 patients in the United States. Kaplan-Meier and Cox regression were used to determine the prognostic factors affecting survival. χ2 test was used to assess the correlation. RESULTS: Incidence of hand and wrist sarcoma was 0.017 per 100 000 persons in 2017 and has not significantly changed since 1975 (p > 0.05). Disease-specific 5-year and 10-year survival for the entire cohort was 90% and 84%, respectively. On multivariate analysis race "others," histology other than "osteosarcoma," "undifferentiated" grade, and size "≥6 cm" were predictors of worse disease-specific survival. Cross-tabulation of race with other significant prognostic factors on univariate analysis revealed a significant correlation of race with every other significant prognostic factor except for grade. CONCLUSIONS: The current study is an analysis of a population-based registry reporting incidence and survival data for patients with sarcoma of hand and wrist. Independent prognostic factors include race, histology, grade, and size. There is a lack of improvement in survival over the last four decades.