卵巢上皮癌中ING4基因启动子的甲基化状态及其临床意义

目的：探讨卵巢上皮癌中ING4基因启动子的甲基化状态及其临床意义。方法：收集2005年7月至2012年6月哈尔滨医科大学附属第一医院行全面分期手术并经病理检查确诊的150例卵巢上皮癌组织标本，并以同期因子宫肌瘤或子宫腺肌症行子宫全切除术或次全切除术并经病理检查确诊为正常卵巢组织的150例标本作为对照组。采用甲基化特异性PCR（MSP）技术检测卵巢上皮癌组织与正常卵巢组织中ING4基因启动子的甲基化状态，蛋白印迹法检测1NG4蛋白的表达，并分析ING4基因启动子的甲基化状态与卵巢上皮癌临床病例特征的关系。结果：卵巢上皮癌组织中ING4基因启动子的甲基化阳性率为42．7％（64／150），明显高于正常卵巢组织（4％，6／150），差异有统计学意义（P〈0．05）。ING4基因启动子甲基化阳性的卵巢上皮癌组织中ING4蛋白表达阴性或弱阳性；1NG4基因启动子甲基化阴性的卵巢上皮癌和正常卵巢组织中ING4蛋白表达阳性；在64例1NG4基因启动子甲基化的卵巢上皮癌组织中，ING4蛋白表达强度与ING4基因启动子的甲基化程度呈负相关（r=-0．435，P〈0．05）。卵巢上皮癌组织中，1NG4基因甲基化的阳性率随着手术病理分期和组织学分级的增加而增加（P〈0．05）；卵巢透明细胞癌（55．6％，10／18）和卵巢子宫内膜样癌（59-3％，16／27）中ING4基因甲基化的阳性率显著高于浆液性囊腺癌（33．9％，20／59）和粘液性囊腺癌（39．1％，18／46）（P〈0．05）；ING4基因启动子的甲基化状态与患者的年龄、有无腹水及淋巴结转移均无显著相关性（P〉0．05）。结论：ING4基因启动子的甲基化可能促进了其在卵巢上皮癌组织中的表达失活，进而促进了卵巢上皮癌的生长和分化。

Analysis of the Significance of Status of ING4 Gene Promoter Methylation in Ovarian Epithelial Cancer Tissue

Objective： To investigate the status of ING4 gene promoter methylation and its clinical significance in epithelial ovarian cancer. Methods： 150 cases of ovarian epithelial cancer tissues that were diagnosed by pathological examination after the comprehensive staging operation by the First Affiliated Hospital of Harbin Medical University from July 2005 to June 2012 were collected, and 150 cases of normal ovary tissues which were diagnosed through the pathological examination after the womb total resection caused by the uterine fibroid or adenomyosis in the same period were used as the control group. The methylation specific PCR （MSP） was used to detect the methylation status of ING4 gene promoter, western blot detection was used to investigate the presentation of ING4 protein, the relationship between the methylation status of 1NG4 gene promoters and clinical features of the ovarian epithelial cancer was also analyzed. Results： The positive methylation rate of ING4 gene promoter in epithelial ovarian cancer tissue was 42.7% （64/150）, which was obviously higher than that in the normal ovarian tissue （4%, 6/150）（P〈0.05）. The ING4 protein of the positive methylation ING4 gene promoter in epithelial ovarian cancer tissue presented negative or weakly positive; however, the ING4 protein of the negative methylation 1NG4 gene promoters of epithelial ovarian cancer tissue and normal ovarian tissue presented positive; in 64 cases of methylated 1NG4 gene promoter of epithelial ovarian cancer, the 1NG4 protein presentation intensity of the 1NG4 gene promoter was negatively correlated with methylation level （r= -0.435, P=0.002）. 1NG4 gene methylation positive rate increased along with the growth of surgery pathological staging （P〈0.05） as well as increase with histopathological grade （P〈0.05）; among the different pathological types, ovarian clear cell carcinoma （55.6%, 10/18） and ovarian endometrioid carcinoma ING4 gene in epithelial ovarian cancer methylation-positive rate （59.3% 16/27） was obviously higher than serous adenocarcinoma （33.9%, 20/59） and mucinous cystadenocarcinoma （39.1%, 18/46） （P 〈0.05）; ING4 gene promoter methylation status is unrelated with the patient＇s age, clinical stage, and lymph node metastasis （P〉0.05）. Conclusion： The methylation of ING4 gene promoter may result in the loss of ING4 protein expression in epithelial ovarian cancer, which thus promotes the growth and differentiation of epithelial ovarian cancer.