Prognostic importance of IDH mutations in chondrosarcoma: An individual patient data meta-analysis

Targeting Isocitrate Dehydrogenase (IDH) in Solid Tumors: Current Evidence and Future Perspectives

The isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2) enzymes are involved in key metabolic processes in human cells, regulating differentiation, proliferation, and oxidative damage response. IDH mutations have been associated with tumor development and progression in various solid tumors such as glioma, cholangiocarcinoma, chondrosarcoma, and other tumor types and have become crucial markers in molecular classification and prognostic assessment. The intratumoral and serum levels of D-2-hydroxyglutarate (D-2-HG) could serve as diagnostic biomarkers for identifying IDH mutant (IDHmut) tumors. As a result, an increasing number of clinical trials are evaluating targeted treatments for IDH1/IDH2 mutations. Recent studies have shown that the focus of these new therapeutic strategies is not only the neomorphic activity of the IDHmut enzymes but also the epigenetic shift induced by IDH mutations and the potential role of combination treatments. Here, we provide an overview of the current knowledge about IDH mutations in solid tumors, with a particular focus on available IDH-targeted treatments and emerging results from clinical trials aiming to explore IDHmut tumor-specific features and to identify the clinical benefit of IDH-targeted therapies and their combination strategies. An insight into future perspectives and the emerging roles of circulating biomarkers and radiomic features is also included.

Global research development of chondrosarcoma from 2003 to 2022: a bibliometric analysis

Background

Chondrosarcomas are common primary malignant bone tumors; however, comprehensive bibliometric analysis in this field has not yet been conducted. Therefore, this study aimed to explore the research hotspots and trends in the field of chondrosarcoma through bibliometric analysis to help researchers understand the current status and direction of research in the field.

Methods

Articles and reviews related to chondrosarcoma published between 2003 and 2022 were retrieved from the Web of Science. Countries, institutions, authors, journals, references, and keywords in this field were visualized and analyzed using CtieSpace and VOSviewer software.

Results

Between 2003 and 2022, 4,149 relevant articles were found. The number of articles published on chondrosarcoma has increased significantly annually, mainly from 569 institutions in China and the United States, and 81 in other countries. In total, 904 authors participated in the publication of studies related to chondrosarcomas. Over the past 20 years, articles on chondrosarcoma have been published in 958 academic journals, with Skeletal Radiology having the highest number of publications. Furthermore, keywords such as "gene expression," "radiotherapy," "experience," and "apoptosis" have been popular in recent years.

Conclusion

Over the past 20 years, the global trend in chondrosarcoma research has primarily been clinical research, with basic research as a supplement. In the future, communication and exchange between countries and institutions should be strengthened. Further, the future main research hotspots in the field of chondrosarcoma include mutated genes and signaling pathways, precision surgical treatment, proton therapy, radiation therapy, chemotherapy, immunotherapy, and other aspects.

Sarcoma_CellminerCDB: A tool to interrogate the genomic and functional characteristics of a comprehensive collection of sarcoma cell lines

Sarcomas are a diverse group of rare malignancies composed of multiple different clinical and molecular subtypes. Due to their rarity and heterogeneity, basic, translational, and clinical research in sarcoma has trailed behind that of other cancers. Outcomes for patients remain generally poor due to an incomplete understanding of disease biology and a lack of novel therapies. To address some of the limitations impeding preclinical sarcoma research, we have developed Sarcoma_CellMinerCDB, a publicly available interactive tool that merges publicly available sarcoma cell line data and newly generated omics data to create a comprehensive database of genomic, transcriptomic, methylomic, proteomic, metabolic, and pharmacologic data on 133 annotated sarcoma cell lines. The reproducibility, functionality, biological relevance, and therapeutic applications of Sarcoma_CellMinerCDB described herein are powerful tools to address and generate biological questions and test hypotheses for translational research. Sarcoma_CellMinerCDB (https://discover.nci.nih.gov/SarcomaCellMinerCDB) aims to contribute to advancing the preclinical study of sarcoma.

Characterization of purinergic signaling in tumor-infiltrating lymphocytes from lower- and high-grade gliomas

Malignant gliomas are highly heterogeneous glia-derived tumors that present an aggressive and invasive nature, with a dismal prognosis. The multi-dimensional interactions between glioma cells and other tumor microenvironment (TME) non-tumoral components constitute a challenge to finding successful treatment strategies. Several molecules, such as extracellular purines, participate in signaling events and support the immunosuppressive TME of glioma patients. The purinergic signaling and the ectoenzymes network involved in the metabolism of these extracellular nucleotides are still unexplored in the glioma TME, especially in lower-grade gliomas (LGG). Also, differences between IDH-mutant (IDH-Mut) versus wild-type (IDH-WT) gliomas are still unknown in this context. For the first time, to our knowledge, this study characterizes the TME of LGG, high-grade gliomas (HGG) IDH-Mut, and HGG IDH-WT patients regarding purinergic ectoenzymes and P1 receptors, focusing on tumor-infiltrating lymphocytes. Here, we show that ectoenzymes from both canonical and non-canonical pathways are increased in the TME when compared to the peripheral blood. We hypothesize this enhancement supports extracellular adenosine generation, hence increasing TME immunosuppression.

Mitochondrial isocitrate dehydrogenase impedes CAR T cell function by restraining antioxidant metabolism and histone acetylation

The efficacy of chimeric antigen receptor (CAR) T cell therapy is hampered by relapse in hematologic malignancies and by hyporesponsiveness in solid tumors. Long-lived memory CAR T cells are critical for improving tumor clearance and long-term protection. However, during rapid ex vivo expansion or in vivo tumor eradication, metabolic shifts and inhibitory signals lead to terminal differentiation and exhaustion of CAR T cells. Through a mitochondria-related compound screening, we find that the FDA-approved isocitrate dehydrogenase 2 (IDH2) inhibitor enasidenib enhances memory CAR T cell formation and sustains anti-leukemic cytotoxicity in vivo. Mechanistically, IDH2 impedes metabolic fitness of CAR T cells by restraining glucose utilization via the pentose phosphate pathway, which alleviates oxidative stress, particularly in nutrient-restricted conditions. In addition, IDH2 limits cytosolic acetyl-CoA levels to prevent histone acetylation that promotes memory cell formation. In combination with pharmacological IDH2 inhibition, CAR T cell therapy is demonstrated to have superior efficacy in a pre-clinical model.

Clinico-Genomic Profiling of Conventional and Dedifferentiated Chondrosarcomas Reveals TP53 Mutation to Be Associated with Worse Outcomes

PURPOSE

Chondrosarcomas are the most common primary bone tumor in adults. Isocitrate dehydrogenase 1 (IDH1) and IDH2 mutations are prevalent. We aimed to assess the clinico-genomic properties of IDH mutant versus IDH wild-type (WT) chondrosarcomas as well as alterations in other genes.

EXPERIMENTAL DESIGN

We included 93 patients with conventional and dedifferentiated chondrosarcoma for which there were available clinical next-generation sequencing data. Clinical and genomic data were extracted and compared between IDH mutant and IDH WT chondrosarcomas and between TP53 mutant and TP53 WT chondrosarcomas.

RESULTS

IDH1 and IDH2 mutations are prevalent in chondrosarcoma (50.5%), more common in chondrosarcomas arising in the extremities, associated with higher age at diagnosis, and more common in dedifferentiated chondrosarcomas compared with grades 1-3 conventional chondrosarcoma. There was no difference in survival based on IDH mutation in univariate and multivariate analyses. TP53 mutation was the next most prevalent (41.9%) and is associated with worse overall survival and metastasis-free survival in both univariate and multivariate analyses. TP53 mutation was also associated with higher risk of recurrence following curative-intent surgery and worse survival among patients that presented with de novo metastatic disease.

CONCLUSIONS

IDH mutations are prevalent in chondrosarcoma though were not associated with survival outcomes in this cohort. TP53 mutations were the next most common alteration and were associated with worse outcomes.

IDH-negative chondrosarcoma with metachronous dedifferentiation only in the metastatic site-A diagnostic pitfall

Dedifferentiated chondrosarcoma is a subtype of chondrosarcoma with a biphasic histological appearance of a chondrosarcoma component transitioning to a high-grade, noncartilaginous sarcoma. It is particularly difficult to confirm the diagnosis when a sarcoma lacking cartilaginous component occurs at a distant location from the primary lesion. The patient was a 72-year-old woman with multiple lesions in the pelvis, lungs, and liver, 18 months after resection of grade 2 central chondrosarcoma of the sternum. Imaging showed no cartilage component in any location. Although a needle biopsy from the pelvic region confirmed the diagnosis as high-grade sarcoma without a cartilage component, it was difficult to distinguish between a new primary sarcoma and metachronous metastatic lesions from patient's known prior dedifferentiated chondrosarcoma. We therefore performed a comparative molecular analysis by whole-exome sequencing of the biopsy sample and the resected sternal central chondrosarcoma. Both lesions had no IDH1/2 mutations but shared 19 somatic mutations and wide-range chromosomal losses, indicating similar origin. This case illustrates the challenge is coupling a diagnosis of metastatic dedifferentiated chondrosarcoma when no chondroid component is evident. Our study also highlights the benefit of genomic analysis in this differential diagnosis, especially in the context of dedifferentiated chondrosarcoma lacking IDH1/2 mutations.

Establishment and characterization of a novel dedifferentiated chondrosarcoma cell line, SMU-DDCS, harboring an IDH1 mutation

Dedifferentiated chondrosarcoma (DDCS) is a high-grade subtype with a bi-morphic histological appearance of a conventional chondrosarcoma component and it can abruptly transition to a high-grade non-cartilaginous sarcoma. To better understand the biological features of DDCSs and to help develop new therapies, a novel DDCS cell line, SMU-DDCS, was established. Tissue from an open biopsy of a tumor resected from a 75-year-old patient was subjected to primary culture. The cell line was established and authenticated by assessing DNA microsatellite short tandem repeats. The cells maintained in monolayer cultures exhibited constant growth, spheroid formation, and high invasive capacity. Out of the four mice inoculated with SMU-DDCS cells, tumors developed in three mice after 2 weeks. R132C mutation was found in the IDH1 but not the IDH2 genomic DNA sequence of SMU-DDCS cells. SMU-DDCS cells exhibited low chemosensitivity to doxorubicin, methotrexate, and cisplatin. This SMU-DDCS cell line harboring an IDH1 mutation will be a useful tool for investigating DDCS development and for evaluating novel therapeutic agents against it.

IDH mutations in G2-3 conventional central bone chondrosarcoma: a mono institutional experience

BACKGROUND

Heterozygous isocitrate dehydrogenase (IDH) mutations occur in about half of conventional central bone chondrosarcomas (CCBC). Aim of this study was to assess the frequency and prognostic impact of IDH mutations in high grade CCBC patients.

METHODS

64 patients with G2 and G3 CCBC were included. DNA extraction, PCR amplification of IDH1/2 exon 4s, and sequencing analysis with Sanger were performed.

RESULTS

IDH mutations were detected in 24/54 patients (44%): IDH1 in 18, IDH2 in 4, and both IDH1/2 in 2 patients. The frequency of mutations was 37% in G2 vs. 69% in G3 (p = 0.039), and 100% in three Ollier disease associated chondrosarcoma. 5-year overall survival (OS) at 124 months (range 1-166) was 51%, with no significant difference based on the IDH mutational status: 61% in IDHmut vs. 44% in IDH wild type (IDHwt). The 5-year relapse free survival (RFS) was 33% (95% CI:10-57) for IDHmut vs. 57% (95%CI: 30-77) for IDHwt. Progression free survival (PFS) was 25% (95%CI:1-65) IDHmut vs. 16% (95%CI: 0.7-52) IDHwt. 55% (5/9) of IDHmut G2 became higher grade at the recurrence, as compared with 25% (3/12) of G2 IDHwt.

CONCLUSIONS

This study shows a higher frequency of IDH mutations in G3 CCBC as compared with G2. No significant differences in OS, RFS, and PFS by mutational status were detected. After relapse, a higher rate of G3 for IDH mutated CCBC was observed.

Clear cell chondrosarcoma: a review of clinicopathologic characteristics, differential diagnoses, and patient management

Clear cell chondrosarcoma (CCC), an extremely rare primary bone tumor, is currently classified by the World Health Organization as a low-grade malignant cartilaginous neoplasm. Clinically, CCC occurs primarily in males with a peak incidence in the third to fifth decades of life, and occasionally, it presents in skeletally immature patients. Unlike conventional chondrosarcoma, CCC has a predilection for the epiphysis of long bones and often displays radiologic features reminiscent of chondroblastoma. The recommended treatment is wide operative resection. CCC has a local recurrence rate of approximately 30%, and nearly 20% cases metastasize mainly to bone and lung often a decade after surgical intervention. Incomplete excision or curettage is associated with a high rate of recurrence. Histologically, the process is characterized by infiltrative lobules and sheets of round to oval cells with abundant cleared cytoplasm and well-defined cell borders associated with trabecula of osteoid and woven bone, scattered osteoclasts, and foci of conventional low-grade chondrosarcoma in about one-half of cases. Correlation with clinical and radiologic characteristics, such as epiphyseal location and young patient age, assists in establishing a correct diagnosis. Pathologic diagnosis of CCC is complicated by the low diagnostic accuracy of core needle biopsy, overlapping histologic features with other matrix-rich primary bone tumors, and a lack of a specific immunohistochemical and molecular profile. DNA methylation-based profiling classifier (sarcoma classifier) is one recent technologic advancement that may help to confirm the histopathological diagnosis of CCC or indicate the need for thorough reassessment in cases where results contradict previous conventional findings.

B-cell lymphoma 2 family members and sarcomas: a promising target in a heterogeneous disease

Targeting the B-cell lymphoma 2 (Bcl-2) family proteins has been the backbone for hematological malignancies with overall survival improvements. The Bcl-2 family is a major player in apoptosis regulation and, has captured the researcher's interest in the treatment of solid tumors. Sarcomas are a heterogeneous group of diseases, comprising several entities, with high morbidity and mortality and with few specific therapies available. The treatment for sarcomas is based on platinum regimens, with variable results and poor outcomes, especially in advanced lesions. The high number of different sarcoma entities makes treatment standardization as well as the performance of clinical trials difficult. The use of Bcl-2 family members modifiers has revealed promising results in in vitro and in vivo models and may be a valid option, especially when used in combination with chemotherapy. In this article, a revision of these results and possibilities for the use of Bcl-2 family members inhibitors in sarcomas was performed.

Dedifferentiated Chondrosarcoma from Molecular Pathology to Current Treatment and Clinical Trials

Dedifferentiated chondrosarcoma (DDCS) is a rare subtype of chondrosarcoma, a primary cartilaginous malignant neoplasm. It accounts for up to 1-2% of all chondrosarcomas and is generally associated with one of the poorest prognoses among all chondrosarcomas with the highest risk of metastasis. The 5-year survival rates range from 7% to 24%. DDCS may develop at any age, but the average presentation age is over 50. The most common locations are the femur, pelvis humerus, scapula, rib, and tibia. The standard treatment for localised disease is surgical resection. Most patients are diagnosed in unresectable and advanced stages, and chemotherapy for localised and metastatic dedifferentiated DDCS follows protocols used for osteosarcoma.

IMMUNOHISTOCHEMICAL ANALYSIS BY KI67 AND IDH1 IN PATIENTS WITH CHONDROSARCOMA

Objective

To perform an immunohistochemical evaluation using the IDH1 and Ki67 markers in patients who underwent treatment for chondrosarcoma in a reference service center in Brazil.

Methods

Retrospective analytical observational study using medical records of patients diagnosed with chondrosarcoma. Besides the epidemiological and clinical profile, important variables for prognosis and correlation with immunohistochemical analysis results with Ki67 and IDH1 markers were evaluated.

Results

Histopathological examinations by immunohistochemistry of 56 patients were analyzed, 52% of which were women, with the age group 20-60 years being more prevalent. Grade 1 and 2 histological subtypes corresponded to most chondrosarcomas. The femur, humerus, and tibia were the most frequent anatomical sites. Most tumors (59%) were larger than 8 cm. Ki67 expression was very low (< 10%) in 98% of patients. The analysis of IDH1 was positive in 43% of the cases. The correlation between IDH1 positivity and tumor size was statistically significant, but regarding survival, we observed no significance.

Conclusion

Immunohistochemical analysis using IDH1 and Ki67 markers in patients with conventional chondrosarcoma is not useful for prognostic guidance.Level of Evidence II, Prognostic Assessment, Results of Immunohistochemical Tests and Correlation with Survival.

Conventional Chondrosarcoma of the Rib Cage and Sternum: Clinicopathological and Molecular Analysis of 27 Patients Treated at a Single Institution

Conventional chondrosarcoma of the chest wall is rare, accounting for 15% of cases. Our purpose was to document clinicopathological, imaging and outcome results from a novel set of chest wall chondrosarcomas, and to analyze for <I>IDH</I> mutations and novel molecular alterations. Gross and microscopic pathology, imaging and clinical charts were reviewed. Targeted next-generation sequencing was performed to identify somatic mutations and copy number alterations. The cohort consisted of 27 patients: 16 men and 11 women (mean age 51 years; range 23-76). Palpable mass was the most common presentation. Five were discovered incidentally. Among 20 tumors with complete imaging, 15 arose from a rib and 5 from the sternum. Seven rib tumors were central/intramedullary, 5 were periosteal, 2 were secondary peripheral chondrosarcomas, and one was indeterminate. Among sternal tumors, 4 were central/intramedullary and one was periosteal. Half the periosteal tumors arose from the costochondral junctional cartilage (CCJ). Periosteal chondrosarcomas were sometimes mistaken for extraskeletal masses on initial clinical or radiological examinations. Fifty-nine percent of all tumors were grade 1 and 41% were grade 2. None were dedifferentiated chondrosarcomas. Heterozygous <I>IDH1</I> mutation was detected in one tumor and heterozygous <I>RAD50</I> mutation in another. Local recurrence(s) happened in 41% and metastasis in 41%. Grade had strong association with local recurrence (25% grade 1 vs. 64% grade 2 [p=0.0447]), metastatic recurrence (19% grade 1 vs. 73% grade 2 [p=0.0058]), and survival. Although chest wall chondrosarcomas share morphologic and molecular features with other chondrosarcomas, there is a much higher incidence of periosteal chondrosarcomas. <I>IDH</I> mutant tumors are uncommon. Early diagnosis and margin-negative resection is treatment of choice since chondrosarcomas are chemo- and radioresistant.

Intracranial Metastasis of Extracranial Chondrosarcoma: Systematic Review With Illustrative Case

BACKGROUND

Cerebral chondrosarcoma metastases are rare and aggressive neoplasms. The rarity of presentation has precluded rigorous analysis of diagnosis, risk factors, treatment, and survival. We analyzed every reported case through exhaustive literature review. We further present the first case with Maffucci syndrome.

METHODS

Three databases, PubMed, Embase, and Google Scholar, and crossed references were queried for cerebral chondrosarcoma metastases. Extracted variables included demographics, risk factors, tumor characteristics, interventions, and outcomes. Univariate and multivariate analyses were performed.

RESULTS

Fifty-six patients were included from 1,489 literature results. The average age at brain metastasis was 46.6±17.6 years and occurred at a median of 24±2.8 months from primary diagnosis. Primary tumor histology (dedifferentiated 5.0±1.5 months, mesenchymal 24±3.0 months, conventional 41±7.4 months, p<0.05) and grade (low grade 54±16.7 months vs. high-grade 10±6.4 months, p<0.001) correlated with time interval until brain metastasis. A multiple enchondromatosis syndrome occurred in 13.2% of cases. At time of brain metastases diagnosis, extracranial metastases were identified in 76.2% of cases. Median survival after the development of brain metastasis was 2.0±0.78 months with a 1-year survival of 10.0%. On regression analysis, surgery reduced brain metastasis mortality risk and radiation trended towards reduced mortality risk (surgery: hazard ratio [HR] 0.22, 95% confidence interval [CI] 0.064-0.763, p=0.017; radiation: HR 0.31, 95% CI 0.091-1.072, p=0.064).

CONCLUSION

We present a systematic review of cerebral chondrosarcoma metastases. Primary tumor histology and grade correlate with time until cerebral metastasis. Following cerebral metastasis, these tumors have poor prognosis and modestly benefit from surgery.

Distinct IDH1/2-associated Methylation Profile and Enrichment of TP53 and TERT Mutations Distinguish Dedifferentiated Chondrosarcoma from Conventional Chondrosarcoma

Dedifferentiated chondrosarcoma (DDCS) is a rare high-grade chondrosarcoma characterized by a well-differentiated chondrosarcoma (WDCS) component that abruptly transitions to a high-grade, noncartilaginous sarcomatous component. To date, the molecular pathogenesis of DDCS and its distinction from conventional chondrosarcoma remain poorly understood. By targeted sequencing, we examined the mutational and copy-number profiles of 18 DDCS, including macrodissected WDCS components, compared with 55 clinically sequenced conventional chondrosarcomas. In conjunction with publicly available external data, we analyzed the methylation and expression profiles of 34 DDCS and 94 conventional chondrosarcomas. Isocitrate dehydrogenase 1/isocitrate dehydrogenase 2 (IDH1/IDH2) mutations were present in 36% conventional chondrosarcomas and 71% DDCS. Compared with conventional chondrosarcomas, DDCS had higher frequencies of TP53 and TERT promoter mutations and CDKN2A/B copy-number losses. Paired analysis of macrodissected WDCS and the high-grade components revealed TERT promoter mutations as early events. Despite phenotypic similarities, the percentage of genome with copy-number alterations in DDCS was significantly lower than that in other high-grade sarcomas. Differential methylation analysis revealed reduction of IDH1/IDH2-associated global hypermethylation characteristically seen in conventional chondrosarcoma and a distinct methylation profile in DDCS. The WDCS and high-grade components in DDCS showed similar methylation profiles. These CpG sites were associated with upregulated expression of genes involved in G2-M checkpoints and E2F targets. Genomic profiling revealed enrichment of TP53, TERT promoter, and CDKN2A/B alterations in DDCS. Integrated methylation and gene expression analysis revealed distinct IDH1/IDH2-associated methylation and transcriptional profiles as early events in DDCS, which may underlie the pathogenesis of dedifferentiation in chondrosarcomas.

Significance

DDCS is a rare, high-grade chondrosarcoma with a dismal prognosis. About 50%-80% of DDCS harbor IDH1/IDH2 mutations. We uncover a significant alteration of IDH-associated methylation profile in DDCS, which we propose is key to the progression to dedifferentiation. In this context, the potential effect of the use of IDH inhibitors is unclear but important to address, as clinical trials of selective IDH1 inhibitors showed worse outcome in DDCS.

Clinicopathological features and prognostic outcomes of molecularly defined entities in the new edition of the WHO classification of sinonasal carcinoma

Introduction

We investigated the clinicopathological features and prognoses of the new molecularly defined entities in latest edition of the World Health Organization (WHO) classification of sinonasal carcinoma (SNC).

Methods

Integrated data were combined into an individual patient data (IPD) meta-analysis.

Results

We included 61 studies with 278 SNCs including 25 IDH2-mutant, 41 NUT carcinoma, 187 SWI/SNF loss, and 25 triple negative SNCs (without IDH2 mutation, NUTM1 rearrangement, and SWI/SNF inactivation) for analyses. Compared to other molecular groups, NUT carcinoma was associated with a younger age at presentation and an inferior disease-specific survival. Among SNCs with SWI/SNF inactivation, SMARCB1-deficient tumors presented later in life and were associated with a higher rate of radiotherapy administration. SMARCA4-deficiency was mostly found in teratocarcinosarcoma while SMARCB1-deficient tumors were associated with undifferentiated carcinoma and non-keratinizing squamous cell carcinoma.

Conclusion

Our study facilitates our current understanding of this developing molecular-defined spectrum of tumors and their prognoses.

Atypical cartilage in type II germ cell tumors of the mediastinum show significantly different patterns of IDH1/2 mutations from conventional chondrosarcoma

Neoplastic cartilage is a common component of teratomas in type II germ cell tumors. Although IDH1/2 mutations have been well-described in somatic cartilaginous tumors, ranging from benign enchondromas to highly aggressive dedifferentiated chondrosarcomas, the presence of IDH1/2 mutations in cartilaginous neoplasms arising from germ cell tumors has not been previously investigated. To better understand the relationship between these tumors and their bone/soft tissue counterpart, we studied the IDH1/2 mutational status of 20 cases of primary mediastinal mixed germ cell tumors with areas of readily identifiable cartilaginous differentiation. Our study found that cartilaginous lesions arising in germ cell tumors have a different frequency and distribution of IDH1/2 mutations compared to those at somatic sites. We identified IDH1/2 mutations in only 15% (3/20) of cases, compared to a frequency in the literature among differentiated chondroid tumors of bone and soft tissue of 54%, a highly significant decreased frequency (p = 0.0011; chi-square test). Furthermore, they were exclusively IDH2 R172 mutations that occurred at a non-significant, increased frequency in the germ cell tumor group compared to conventional chondrosarcoma (15% vs. 5%, respectively, p > 0.05, chi-square test). The unexpected finding, therefore, was entirely attributable to the absence of IDH1 R132 mutation in chondroid neoplasia of germ cell origin (p < 0.00001, Fisher exact test). Our results suggest that a subset of cartilaginous lesions arising within type II germ cell tumors have a similar oncogenic mechanism to their bone/soft tissue counterpart but that the majority form using different oncogenic mechanisms compared to their somatic counterparts.

Clinical Characteristics and Prognostic Risk Factors of Parasellar Chondrosarcoma

Background: Parasellar chondrosarcomas are extremely rare. This study describes the characteristics of parasellar chondrosarcoma and analyzes the risk factors and prognosis based on the resection degree. Methods: Fifteen patients with pathologically diagnosed parasellar chondrosarcoma were retrospectively analyzed for the clinical data, surgical methods, and prognosis to identify relationships between the surgical resection degree, tumor recurrence, and imaging characteristics. Results: Twelve patients had eye dysfunction and ptosis. Differentiation from other parasellar tumors by imaging is difficult. The preoperative Karnofsky Performance Scale (KPS) score positively correlated with the tumor resection degree (p = 0.026) and negatively correlated with the maximum tumor diameter (p = 0.001). Tumor recurrence negatively correlated with the resection degree (p = 0.009). The postoperative KPS score positively correlated with the preoperative KPS score (p < 0.001) and tumor resection degree (p = 0.026), and negatively correlated with the maximum tumor diameter (p = 0.016) and age (p = 0.047). An improved KPS score positively correlated with the tumor resection degree (p = 0.039). Patients who underwent total resection of the chondrosarcoma had longer progression-free survival than those who underwent partial resection (p = 0.0322). Conclusion: Parasellar chondrosarcomas are difficult to resect completely. Preoperative KPS score is an important factor for the degree of resection. KPS score, age, maximum tumor diameter, and resection degree may be important prognostic factors.

Effect of surgery and radiotherapy on overall survival in patients with chondrosarcoma: A SEER-based study

PURPOSE

Chondrosarcoma is an orthopedic malignancy, and the purpose of this study was to evaluate the effect of surgery and radiotherapy (RT) on the survival of patients with chondrosarcoma.

METHODS

Data were obtained from the SEER database for patients diagnosed with chondrosarcoma between 1988 and 2015. All patients were divided into surgery, RT, surgery + RT, and no surgery/no RT groups. Kaplan-Meier curves were used to analyze the overall survival and cancer-specific survival of patients in different treatment groups. The propensity score matching was used to balance baseline covariates between patients in the surgery and surgery + RT groups and in the RT and surgery + RT groups.

RESULTS

Data from 3756 patients with chondrosarcoma were included in this study. The number of patients who underwent surgery, RT, surgery + RT, and no surgery or RT was 2885 (76.8%), 112 (3.0%), 403 (10.7%), and 356 (9.5%), respectively. Multivariate Cox regression models showed that treatment modality was independent risk factor for OS and CSS. Before PSM, Kaplan-Meier curves showed that OS and CSS were highest in the surgery group and lowest in the RT group. After PSM, although there was no significant difference in OS (p = .13) and CSS (p = .22) between the surgery and surgery + RT group, OS was longer in the surgery group than in the surgery + RT group. Additionally, OS (p < .001) and CSS (p = .009) were longer in the surgery + RT group than in the RT group after PSM.

CONCLUSION

Surgical resection was the key approach for the treatment of chondrosarcoma, while RT confers no significant advantage in improving patient survival time.

Clinical usefulness of 2-hydroxyglutarate as a biomarker in IDH-mutant chondrosarcoma

•

2-HG is expected to be a useful biomarker for diagnosing and treating IDH-mutant tumors.

•

Both intratumoral and serum levels of 2-HG were significantly higher in IDH-mutant tumors.

•

Serum 2-HG levels were correlated with tumor volume and tumor progression.

•

MR spectroscopy (MRS) detected 2-HG peaks in a xenograft model of IDH-mutant chondrosarcoma.

•

In vivo MRS can be a useful tool for determining the therapeutic effect of mutant IDH inhibitors.

Background

Chondrosarcoma is a common form of malignant bone tumor with limited treatment options. Approximately half of chondrosarcomas harbor gain-of-function mutations in isocitrate dehydrogenase (IDH), and mutant IDH produces 2-hydroxyglutarate (2-HG), which is an oncometabolite that contributes to malignant transformation. Therefore, inhibiting 2-HG production is a novel and promising treatment for advanced chondrosarcoma. 2-HG is also expected to be a useful biomarker for the diagnosis and treatment of IDH-mutant tumors. However, few studies have confirmed this using chondrosarcoma clinical specimens. Non-invasive monitoring of 2-HG levels is useful to infer that mutant IDH inhibitors reach therapeutic targets and to confirm their therapeutic efficacy in clinical practice.

Methods

To evaluate the clinical utility of 2-HG as a surrogate biomarker for diagnosis and therapeutic efficacy, we measured intra-tumor and serum levels of 2-HG using frozen tissues and peripheral blood from patients with chondrosarcoma. We also developed a non-invasive method to detect intra-tumor 2-HG signals in vivo using magnetic resonance spectroscopy (MRS)

Results

Both intratumoral and serum 2-HG levels were significantly elevated in IDH-mutant tumors, and these levels correlated with decreased survival. Furthermore, we detected intratumoral 2-HG peaks using MR spectroscopy in a xenograft model of IDH-mutant chondrosarcoma, and observed that 2-HG peak signals disappeared after administering an inhibitor of mutant IDH1.

Conclusions

Our findings suggest that both intratumoral and serum 2-HG levels represent potentially useful biomarkers for IDH-mutant tumors and that the 2-HG signal in MR spectra has potential value as a non-invasive biomarker. Taken together, these findings may positively impact the clinical development of mutant IDH inhibitors for the treatment of advanced chondrosarcoma.

Chondrosarcoma and Chordoma of the Skull Base and Spine: Implication of Tumor Location on Patient Survival

BACKGROUND

Chondrosarcoma and chordoma are often grouped together because of their similar anatomic locations, clinical presentations, histopathological and radiological findings, and growth patterns. In the present study, we investigated the clinical and prognostic differences of chondrosarcomas and chordomas of the skull base and spine.

METHODS

We accessed the Surveillance, Epidemiology, and End Results database to search for patients from 2000 to 2018 with chondrosarcomas and chordomas of the skull base and spine for inclusion in the present study.

RESULTS

We included 1346 and 1536 cases of chondrosarcoma and chordoma for analysis, respectively. Chondrosarcomas of the cranial base and spine were seen in younger patients and were associated with a larger tumor size compared with chordomas. Among the tumors of the skull base, chondrosarcomas were more common in women, with a male predominance found for chordomas. We also observed a male predilection for both spinal chondrosarcomas and chordomas. Distinct metastatic patterns were found for chondrosarcomas versus chordomas, and spinal chondrosarcomas showed a greater risk of distant metastases at presentation compared with spinal chordomas. Cranial base chondrosarcomas were associated with superior outcomes compared with chordomas. However, we demonstrated an opposite survival pattern for spinal chondrosarcomas and chordomas.

CONCLUSIONS

Chondrosarcomas and chordomas have divergent clinical manifestations and prognoses depending on the anatomic location.

Therapeutic Targets and Emerging Treatments in Advanced Chondrosarcoma

Due to resistance to standard anticancer agents, it is difficult to control the disease progression in patients with metastatic or unresectable chondrosarcoma. Novel therapeutic approaches, such as molecule-targeting drugs and immunotherapy, are required to improve clinical outcomes in patients with advanced chondrosarcoma. Recent studies have suggested several promising biomarkers and therapeutic targets for chondrosarcoma, including IDH1/2 and COL2A1. Several molecule-targeting agents and immunotherapies have shown favorable antitumor activity in clinical studies in patients with advanced chondrosarcomas. This review summarizes recent basic studies on biomarkers and molecular targets and recent clinical studies on the treatment of chondrosarcomas.

Metabolic Pathways and Targets in Chondrosarcoma

Chondrosarcomas are the second most common primary bone malignancy. Chondrosarcomas are characterized by the production of cartilaginous matrix and are generally resistant to radiation and chemotherapy and the outcomes are overall poor. Hence, there is strong interest in determining mechanisms of cancer aggressiveness and therapeutic resistance in chondrosarcomas. There are metabolic alterations in chondrosarcoma that are linked to the epigenetic state and tumor microenvironment that drive treatment resistance. This review focuses on metabolic changes in chondrosarcoma, and the relationship between signaling via isocitrate dehydrogenase 1 and 2 (IDH1 and IDH2), hedgehog, PI3K-mTOR-AKT, and SRC, as well as histone acetylation and angiogenesis. Also, potential treatment strategies targeting metabolism will be discussed including potential synergy with immunotherapies.

Prognostic importance of IDH mutations in chondrosarcoma: An individual patient data meta-analysis

Introduction

IDH1/2 mutations are prevalent in cartilaginous tumors including chondrosarcoma. This meta‐analysis using individual patient data (IPD) aimed to investigate the clinical and prognostic association of these mutations in chondrosarcoma patients.

Methods

Two electronic databases including PubMed and Web of Science were searched for relevant data. We included studies providing IPD of chondrosarcoma with available IDH1/2 mutational status for meta‐analysis. Chi‐square and t‐test were performed to compare the groups with and without IDH1/2 mutations. For survival analysis, log‐rank test, and Cox proportional hazards model were used to investigate the association of IDH mutations with patient outcomes.

Results

Fourteen studies with 488 patients were analyzed. IDH1 and IDH2 mutations were detected in 38.7% and 12.1% of cases, respectively. IDH1/2 mutations were significantly associated with an older age (p = 0.003), tumor origins (p < 0.001), tumor grades (p < 0.001), larger diameter (p = 0.003), relapse (p = 0.014), and patient mortality (p = 0.04). Multivariate Cox regression analysis adjusted for age, gender, tumor grade, and tumor sites confirmed the negative impact of IDH1/2 mutations on patient overall survival (HR = 1.90; 95% CI = 1.06–3.42; p = 0.03).

Conclusion

Our meta‐analysis demonstrated the distinct characteristics of IDH1/2‐mutated chondrosarcomas in comparison to those without mutations. These mutations could serve as an independent prognostic biomarker to better prognosticate patient outcomes and design appropriate treatment plans.