骨肉瘤组织与血浆中RASSF1A甲基化的检测及其临床诊断意义

【目的】寻求有助于骨肉瘤临床诊断的分子生物学标志物。【方法】甲基化特异性 PCR 法检测30例骨肉瘤患者肿瘤组织和血浆及15例健康志愿者骨组织和血浆中 RASSF1A 启动子甲基化情况。统计分析RASSF1A 甲基化与患者性别、年龄、肿瘤位置、肿瘤分化、肿瘤转移等临床病理特征的相关性。【结果】正常骨组织及血浆中均未检测到 RASSF1A 基因启动子区的甲基化。骨肉瘤组织中 RASSF1A 甲基化阳性率为40％（12／30），血浆甲基化阳性率为26．7％（8／30）。12例肿瘤组织甲基化阳性患者其血浆甲基化阳性共8例，癌组织和血浆 RASSF1A 甲基化一致率为66．7％（8／12），18例癌组织甲基化阴性其血浆甲基化也为阴性，Kappa 一致性检验显示骨肉瘤组织和血浆中 RASSF1A 甲基化水平具有一致性（κ＝0．133，P ＜0．05）。骨肉瘤组织及血浆中 RASSF1A 甲基化阳性率显著高于正常骨组织及血浆的甲基化阳性率（ P ＜0．05），且骨肉瘤组织和血浆中 RASSF1A 甲基化水平与患者的性别、年龄、肿瘤位置无关（ P ＞0．05），而与肿瘤的分化及有无远处转移有关（ P ＜0．05）。【结论】骨肉瘤患者血浆中 RASSF1A 启动子甲基化与骨肉瘤组织中变化具有一致性，可作为骨肉瘤患者临床诊断的一个辅助指标。

Osteosarcoma Tissue and Plasma and Its Clinical Diagnostic Significance

Objective]To further investigate the mechanism involved in pathogenesis of osteosarcoma and to discuss the feasibility of methylation status in plasma as a biomarker for clinical detection of osteosarcoma .Methods] Methylation‐specific PCR (MSP) was applied to determine RASSF1A methylation in 30 cases of osteosarcoma tissues and plasma from the same patient and 15 cases of normal bone tissues and plasma from healthy volunteers .The correlation between methylation of RASSF1A gene and clinical‐pathological features such as gender ,age ,tumor location ,tumor differentiation and tumor distant metastasis was analyzed .Re‐sults] RASSF1A methylation was not detected in normal bone tissue and plasma .Hypermethylation of RASSF1A was present in 26 .7% (8/30) of the osteosarcoma plasma samples and 40% (12/30) of the osteo‐sarcoma tissues ,and of the 12 cases of positive RASSF1A methylation ,8 cases were found with RASSF1A methylation both in the cancer tissues and plasma from the same patient ,with a positive consistent rate of 66 .7% (8/12) ,and 18 cases were observed with negative methylation both in the cancer tissues and plasma . Kappa consistency check showed that methylation of RASSF1A gene in osteosarcoma tissue and plasma had consistency (Kappa value was 0 .133 ,P < 0 .05) .In addition ,analysis showed that RASSF1A methylation in osteosarcoma tissue and plasma was significantly higher than that in the normal tissue and plasma ( P < 0 .05) . The methylation of RASSF1A in plasma and cancer tissue had no obvious relationship with gender ,age ,or tumor location ( P > 0 .05) ,but had relationship with tumor differentiation and tumor distant metastasis ( P< 0 .05) .Conclusion]RASSF1A methylation in plasma can partly represent similar changes in cancer tissue from the same patient and may be a promising biomarker for clinical detection of osteosarcoma .