DNA修复酶MGMT及Ki-67在星形细胞瘤中的表达及临床意义

Expressions of DNA repair enzyme MGMT and Ki-67 in human astrocytoma and clinical significances

目的：观察脑星形细胞瘤中DNA修复酶-6氧-甲基鸟嘌呤DNA甲基转移酶（MGMT）及细胞增殖核抗原（Ki-67）蛋白表达及临床意义。方法：69例样本均来源于神经外科手术切除且临床资料完整、术后病理诊断为星形细胞瘤病例，其中Ⅰ-Ⅱ级34例，Ⅲ级21例，Ⅳ级14例。应用免疫组织化学方法（ABC法）检测样本中MGMT及Ki-67蛋白的表达状况，并进行秩和相关等级检验。结果：星形细胞瘤中MGMT蛋白表达阳性率为60.9%，其中，Ⅰ-Ⅱ级、Ⅲ级和Ⅳ级分别为88.2%、23.5%和50.0%。不同分级之间MGMT蛋白表达比较差异均有显著性（P=0.0031），MGMT阳性表达率与肿瘤分级呈负相关（r=-0.3511，P=0.0031）；星形细胞瘤中Ki-67阳性率为62.3%，随肿瘤恶性程度的增加蛋白表达明显增强（P=0.0000），该表达与肿瘤分级呈正相关（r=0.6904，P=0.0000）；并且随Ki-67表达强度的增加，MGMT的表达强度明显下降（P=0.0151），Ki-67与MGMT蛋白表达呈负相关（r=-0.2915，P=0.0151）。结论：星形细胞瘤中MGMT及Ki-67表达与肿瘤恶性程度密切相关，提示MGMT和Ki-67可以作为评价星形细胞瘤预后的生物学指标。

Objective To explore the expressions of DNA repair enzyme 6-methyiguanine-DNA methyltransferase （MGMT） and cell multiplication nuclear antigen （Ki-67） in human astrocytomas and clinical significances. Methods Sixty nine specimens of human astrocytomas （grade Ⅰ--Ⅱ 34 cases, grade Ⅲ ： 21 cases, grade Ⅳ 14 cases） were selected. The expressions of MGMT and Ki-67 were observed with immunohistochemical technique, and the relation between MGMT and Ki-67 was evaluated. Results The positive rate of MGMT in astrocytoma was 60.9%, the positive rates of grade Ⅰ --Ⅱ , grade Ⅲ and grade Ⅳ were 88.2%, 23.5% and 50.0%, respectively. There were significant differences between various grades of tumor （P= 0. 003 1）, and the expression of MGMT had negative correlation with tumor grades （r= -0. 351 1） . The positive rate of Ki-67 was 62.3%, and obviously increased with the grades of tumor （P=0. 000 0）, and the expression of ki-67 had positive correlation with tumor grades （r= 0. 690 4, P= 0.000 0）; the expression of MGMT decreased with the increase of expression of Ki-67 （P=0. 051）, the expression of MGMT had negative correlation with Ki-67 expression （r=-0. 291 5, P= 0. 015 1）. Conclusion The expressions of MGMT and Ki-67 have close correlation with the degrees of malignancy in human astrocytomas. MGMT and Ki-67 may be used as biological parameters to estimate the prognosis of astrocytoma.