骨外骨肉瘤（ESOS）是一种罕见的恶性间叶质肿瘤，起源于软组织。 ESOS 占所有软组织肉瘤的比例不到 1%，并表现出侵袭性行为，极易发生局部复发和远处转移。尽管治疗取得了进展，但 ESOS 的预后仍然很差，五年生存率低于 50%，转移性患者的五年生存率低于 27%。来自患者样本的离体模型是研究预后不良的罕见疾病（例如 ESOS）和确定潜在的新治疗策略的关键工具。在这项工作中，我们建立了一种新型 ESOS 离体肌球模型，从转移性病变到真皮，用于研究和功能测试目的。组织形态学和分子谱证明，离体细胞模型准确地再现了天然肿瘤。通过功能筛选方法，我们能够确定新的个体抗癌药物对不同药物（如罗米地辛、miverbesib）和多种激酶抑制剂的敏感性。总体而言，我们新的 ESOS 离体细胞模型是研究疾病机制和回答基础和转化研究问题的宝贵工具。© 2023。作者。

Extraskeletal osteosarcoma (ESOS) is a rare malignant mesenchymal tumor that originates in the soft tissue. ESOS accounts for less than 1% of all soft tissue sarcomas and exhibits an aggressive behavior with a high propensity for local recurrence and distant metastasis. Despite advances in treatment, the prognosis for ESOS remains poor, with a five-year survival rate of less than 50% and 27% for metastatic patients. Ex vivo models derived from patient samples are critical tools for studying rare diseases with poor prognoses, such as ESOS, and identifying potential new treatment strategies. In this work, we established a novel ESOS ex vivo sarco-sphere model from a metastatic lesion to the dermis for research and functional testing purposes. The ex vivo cell model accurately recapitulated the native tumor, as evidenced by histomorphology and molecular profiles. Through a functional screening approach, we were able to identify novel individual anti-cancer drug sensitivities for different drugs such as romidepsin, miverbresib and to multiple kinase inhibitors. Overall, our new ESOS ex vivo cell model represents a valuable tool for investigating disease mechanisms and answering basic and translational research questions.© 2023. The Author(s).