Osteosarcoma (OS) is a rare malignant primary bone tumours characterized by a high genetic and cell composition heterogeneity. Unfortunately, despite the use of drug combinations and the recent development of immunotherapies, the overall survival has not improved in the last four decades. Due to the key role of the tumour microenvironment in the pathogenesis of OS, a better understanding of its microenvironment is mandatory to develop new therapeutic approaches. From retrospective biological cohorts of OS, we analysed by immunohistochemistry the presence of lipopolysaccharide (LPS)-binding protein (LBP) in diagnostic biopsies with local disease and compared their level of infiltration to patients suffering from metastatic status. LBP is considered as a marker of LPS exposure and can indirectly reflect the presence of Gram-negative microbiota. LBP were detected in the cytoplasm of OS cells as well as in tumour-associated macrophage. Tumour samples of patients with local disease were significantly enriched in LBP compared to tumour tissues of patients with metastatic status. Lung metastatic tissues showed similar level of LBP compared to paired primary tumours. Overall, this study strongly suggests the presence of Gram-negative bacteria in OS tissues and demonstrated their significant differential level according the metastatic status. This tumour-associated microbiome may help in the conceptualisation of new therapeutic approach to trigger efficient therapeutic responses against cancer.

骨肉瘤（OS）是一种罕见的恶性原发性骨肿瘤，其特征是遗传和细胞组成的高度异质性。不幸的是，尽管使用了药物组合并且最近开发了免疫疗法，但在过去的四年中，总体生存率并没有提高。由于肿瘤微环境在 OS 发病机制中的关键作用，因此必须更好地了解其微环境以开发新的治疗方法。从 OS 的回顾性生物学队列中，我们通过免疫组织化学分析了局部疾病诊断活检中脂多糖 (LPS) 结合蛋白 (LBP) 的存在，并将其浸润水平与患有转移状态的患者进行了比较。LBP 被认为是 LPS 暴露的标志物，可以间接反映革兰氏阴性菌群的存在。在 OS 细胞的细胞质以及肿瘤相关巨噬细胞中检测到 LBP。与转移状态患者的肿瘤组织相比，局部疾病患者的肿瘤样本中 LBP 显着富集。与成对的原发性肿瘤相比，肺转移组织显示出相似水平的 LBP。总体而言，这项研究强烈表明 OS 组织中存在革兰氏阴性细菌，并根据转移状态证明了它们的显着差异水平。这种与肿瘤相关的微生物组可能有助于新治疗方法的概念化，以触发针对癌症的有效治疗反应。与转移状态患者的肿瘤组织相比，局部疾病患者的肿瘤样本中 LBP 显着富集。与成对的原发性肿瘤相比，肺转移组织显示出相似水平的 LBP。总体而言，这项研究强烈表明 OS 组织中存在革兰氏阴性细菌，并根据转移状态证明了它们的显着差异水平。这种与肿瘤相关的微生物组可能有助于新治疗方法的概念化，以触发针对癌症的有效治疗反应。与转移状态患者的肿瘤组织相比，局部疾病患者的肿瘤样本中 LBP 显着富集。与成对的原发性肿瘤相比，肺转移组织显示出相似水平的 LBP。总体而言，这项研究强烈表明 OS 组织中存在革兰氏阴性细菌，并根据转移状态证明了它们的显着差异水平。这种与肿瘤相关的微生物组可能有助于新治疗方法的概念化，以触发针对癌症的有效治疗反应。