微小染色体维持蛋白5在骨肉瘤中的表达和意义

Expression and significance of minichromosome maintenance 5 protein in osteosarcoma

目的探讨微小染色体维持蛋白5（MCM5）在骨肉瘤中的表达特征和预后价值。方法用免疫组织化学二步法检测MCM5和细胞核相关抗原（Ki-67）在76例骨肉瘤和32例骨软骨瘤、24例正常骨组织中的表达，探讨其表达水平与临床病理特征的相关性，分析MCM5蛋白表达在骨肉瘤中的预后价值。结果MCM5和Ki-67在76例骨肉瘤组织中均有表达，在骨软骨瘤和正常骨组织中不表达，差异有统计学意义（P〈0．01）；MCM5阳性率与骨肉瘤等级相关（r=0．756，P〈0．01），与有丝分裂计数相关（r=0．643，P〈0．01），与其他临床病理参数无明显相关；MCM5与Ki-67阳性率正相关（r=0．725，P〈0．01），但显著高于后者（P〈0．01）；MCM5高表达组（〉62％）与低表达组（≤62％）生存时间差异有统计学意义（P〈0．05），MCM5阳性率与骨肉瘤预后相关。结论MCM5能反映骨肉瘤的恶性程度，MCM5阳性率越高，骨肉瘤的恶性程度越高；MCM5比Ki-67能检测出更多的骨肉瘤增殖细胞。

Objective To investigate the expression and prognostic role of minichromosome maintenance 5 （MCM5） protein in ostersarcoma. Methods Immunohistochemistry was used to examine the expression of MCM5 and nuclear-associated antigen （Ki-67） in 76 cases of osteosarcoma, 32 cases of osteochondroma and 24 cases of normal bone tissue. The association of the MCM5 expression with clinicopathologic features and the potential value of MCM5 in predicting clinical outcome for patients with osteosarcoma were also investigated. Results All cases of osteosarcoma showed positive nuclear expression of MCM5 and Ki-67, but there was negative expression in osteochondroma and normal bone tissues （P 〈 0. 01 ）. The MCM5 expression had a positive correlations with the histologic grade （r = 0. 755, P 〈 0. 01 ） and the mitotic index （r = 0. 643 ,P 〈 0. 01 ）. There was a positive correlation between the MCM5 and Ki-67 expression in osteosarcoma （ r = 0. 725 ,P 〈 0. 01 ） , and the positive expression rate of MCM5 was significantly higher than that of Ki-67 （P 〈 0. 01 ）. The patients with high MCM5 expression rate （ 〉 52% ） demonstrated shorter overall survival than those with low MCM5 expression rate （ ≤62% ,P 〈 0. 05 ）. COX regression analysis indicated that the MCM5 expression was a prognostic factor for osteosarcoma. Conclusion The MCM5 expression can reflect the degree of malignancy of osteosarcoma. MCM5 has identified a higher percentage of cells in cycle in osteosarcoma than Ki-67.