Bcl-2在儿童骨肉瘤中的表达与细胞凋亡的相关性及临床意义

Bcl-2 expression and apoptosis in pediatric osteosarcoma:correlation and clinical significance

目的探讨Bcl-2基因与细胞凋亡的相关性及在儿童骨肉瘤发生发展中的作用及临床意义。方法选取1998年1月—2010年3月泰山医学院附属医院、泰安市妇幼保健院收治并确诊的儿童骨肉瘤病例41例,均石蜡病理确诊,将接受规范治疗的患儿(包括手术及术前术后的化疗)纳入本组研究范围,共计36例应用免疫组织化学法对36例儿童骨肉瘤组织,20例骨软骨瘤组织中Bcl-2的表达水平进行检测。单因素分析Bcl-2与患儿性别、年龄、原发肿瘤部位、肿瘤直径、病理分型、Enneking分期的相关性。采用DNA末端原位标记法(TUNEL法)检测儿童骨肉瘤及软骨瘤组织中的细胞凋亡,计算凋亡指数(AI)后分析与Survivin及Bcl-2表达的相关性,并对其临床意义进行初步探讨。结果 Bcl-2表达:36例儿童骨肉瘤组织中Bcl-2表达阳性率为47.2%(17/36),对照组20例骨软骨瘤组织中未见表达(P<0.05);Bcl-2阳性表达与性别、年龄、肿瘤部位、肿瘤直径、病理分型无明显相关,与Enneking外科分期及相关,EnnekingI～II期阳性率为30%(6/20),III期阳性率为62.5%(10/16),差异有统计学意义(P<0.05)。说明分期越高,Bcl-2表达越显著。AI范围3.6%～16.4%,均值7.3%,经检验在儿童骨肉瘤组织中细胞AI为(6.66±1.87)%,对照组组为(12.28±3.29)%,两组间差异有统计学意义(P<0.05),说明骨肉瘤中的细胞凋亡减少。AI在Bcl-2阳性组为(4.68±0.57)%和阴性组(6.53±1.65)%两组间差异有显著性(P<0.05)。Bcl-2的表达与AI呈负相关。采用Kaplan-Meier法绘制Bcl-2阳性组和阴性组生存曲线,提示Bcl-2阳性组生存期显著低于阴性表达者。Cox回归模型进行多因素生存分析显示,骨肉瘤的Enneking分期,Bcl-2的表达水平是儿童骨肉瘤预后相关的独立的重要因素。结论 Bcl-2在儿童骨肉瘤中阳性表达与性别、年龄、肿瘤部位、肿瘤直径、病理分型无明显相关,与Enneking分期相关。Bcl-2的阳性表达缩短骨肉瘤患儿的生存时间。Bcl-2的表达均与AI呈负相关。说明Survivin、Bcl-2蛋白可能阻碍了儿童骨肉瘤细胞的凋亡,促进了肿瘤的分裂增殖。多因素分析显示,骨肉瘤Enneking外科分期及Bcl-2的表达为骨肉瘤重要的预后因素。综合分析以上指标对判断儿童骨肉瘤预后有重要的参考价值。

Objective To discuss the correlation between Bcl -2 and apoptosis and its role in the growth and development of pediatric osteosarcoma. Methods Forty - one children of osteosarcoma were selected who had been pathologically con- firmed and treated in the affiliated hospital of Talshan medical university and Taiim maternal and child health hospital from January 1998 to March 2010. Thirty - six children were enrolled into this study who were about to receive standard treat- ment including surgery, preoperative and postoperative chemotherapy. Immunohistochemical method was used to detect the expression of Bcl - 2 in specimens from 36 eases of pediatric osteosarcoma and 20 cases of pediatric osteochondmma. Uni- varlate analysis was conducted on the correlation between Bcl -2 and gender, age, primary tumor site, tumor size, patho- logic type, Enneking stage. Cell apoptosis in pediatric osteosarcoma and osteochondroma was detected by TUNEL. Apoptot- ic index （AI） was calculate and analyzed for its correlation with Survivin and Bcl -2 expression, which was further dis- cussed for clinical significance. Results For expression of Bcl - 2, the positive rate was 47.2% in the 36 cases of pediat- ric ostcosarcoma （17/36） and no positive case was found in the controls（ P 〈 0.05 ） ; the positive expression of Bcl- 2 was not significantly correlated tO gender, age, tumor site, tumor size, and pathologic type （ P 〉 0.05 ）, but correlated to Enneking staging（P 〈 0.05） ;the positive rate was 30% （6/20） in patients of Enneking＇s stage I -II and 62.5% in patients of Enneking＇s stage III, significance was found between them（ P 〈 0.05 ）. It showed that the expression of Bel -2 was positively correlated to pathologic stage. AI values ranged from 3.6% - 16.4%, with an average of 7.3%. Cell AI was （6.66±1. 87） % in children with osteosareoma upon test and （ 12.28 ± 3.29 ） % in control group, the difference was statistically significant between the two groups （P 〈 0.05 ）, which indicated that there was a reduced apoptosis in osteosareoma. AI value was （4.68±0.57）% and（6.53± 1.65 ）% respectively in Bcl- 2 positive group and Bcl- 2 negative group, which showed significant difference（ P 〈 0.05）. The expression of Bcl -2 was negatively correlated with AI. The survival curves made by Kaplan - Meier method indicated that the life span in Bcl - 2 positive group was significantly shorter than that in Bcl - 2 negative group（ P 〈 0. 01 ）. Multivariate survival analysis using Cox regression model showed that Enneking staging and the level of Bcl - 2 expression in osteosareoma were important and independent factors for the prognosis of pediatric os- teosarcoma. Conclusions Positive expression of Bcl - 2 is not obviously correlated with gender, age, tumor location, tumor size, pathologic type in children with osteosarcoma, but correlated with Enneking stage. Positive expression of Bcl - 2 can shorten the life span and the expression of Bcl - 2 is negatively correlated with AI, all of which indicate that Survivin and Bcl - 2 protein may inhibit cell apoptosis and promote the proliferation of tumor cells in pediatric osteosarcoma. Multi- variate analysis indicates that Enneking staging and the level of Bcl - 2 expression in osteosarcoma are important factors for the prognosis of osteosarcoma. In conclusion, the indicators mentioned above are of great value to the prognosis of osteosar- coma in children.