共刺激分子B7-H3在骨肉瘤组织中的表达及临床意义

Expression of costimulatory molecule B7-H3 in human osteosarcoma and its clinical significance

背景与目的:B7-H3是近年来新发现的协同刺激分子B7家族成员,但目前其在骨肿瘤中的表达及作用机制尚不明确。该研究旨在通过检测人骨肉瘤中B7-H3分子的表达,分析其与患者临床病理因素以及术后生存时间之间的关系。方法:采用免疫组织化学法检测61例人骨肉瘤组织、对应癌旁组织及良性骨肿瘤组织中B7-H3分子的表达以及肿瘤浸润T淋巴细胞的浸润程度。结果:骨肉瘤组织中B7-H3分子表达的阳性率为91.8(56/61),而B7-H3在癌旁及骨纤维结构发育不良组织中几乎不表达。B7-H3分子在骨软骨瘤中表达率为56.8%,但染色强度明显弱于骨肉瘤组织。B7-H3的表达与患者的Ennecking分期、是否发生肺转移之间的差异有统计学意义(P<0.05),与肿瘤组织中CD8+T淋巴细胞浸润程度呈负相关(P<0.05),与患者预后呈负相关(P<0.05)。结论:B7-H3在人骨肉瘤中组织异常高表达,并与肿瘤的进展、患者的预后密切相关;B7-H3可能参与了骨肉瘤微环境中的CD8+T细胞功能的调节,促使肿瘤细胞逃避免疫监视。

Background and purpose：B7-H3 is a newly identiifed member of the B7-family of co-stimulatory molecule, and however, its exact role in human osteosarcoma is still unclear. The purpose of this study was to examine the expression of B7-H3 in osteosarcoma tissues and to investigate its correlations with clinicopathological factors and overall survival in patients with osteosarcoma.Methods：The expression of B7-H3 and the intensity of tumor-inifltrating T lymphocytes （TILs） in pathologic specimens of osteosarcoma, osteochondroma and bone ifbrous dysplasia tissues were evaluated by immunohistochemical assay.Results：The expression rate of B7-H3 was 91.8% （56/61） in osteosarcoma lesions, while B7-H3 was barely expressed in adjacent normal tissues and bone ifbrous dysplasia tissues. The intensity of B7-H3 expression in osteochondroma was 56.8%, which was signiifcantly decreased compared with osteosarcoma tissues. Tumor B7-H3 expression was associated with Ennecking stage and pulmonary metastasis, while inversely correlated with the number of tumor-inifltrating CD8＋ T cells （P〈0.05）. Moreover, patients with high tumor B7-H3 levels had a signiifcantly shorter survival time and recurrence time than patients with low tumor B7-H3 levels （P〈0.05）.Conclusion：B7-H3 is overexpressed in human osteosarcoma tissues, and B7-H3 expression is highly correlated with tumor development and overall patients’ prognosis. Moreover, overexpression of B7-H3 in tissues can relfect CD8＋T cell inifltration and may help tumor cells avoid immune surveillance.