SPOCK2基因表观失活在卵巢子宫内膜异位症恶变中的作用

摘要

目的 通过比较卵巢子宫内膜异位症(内异症)恶变患者的恶变组织、异位内膜组织和在位内膜组织中SPOCK2基因的甲基化及蛋白表达情况,探讨该基因的表观失活在卵巢内异症恶变中的作用.方法 选择2005年1月至2011年1月在中国医科大学附属盛京医院妇产科住院手术、并经术后病理确诊为卵巢内异症恶变患者22例的病理石蜡标本为恶变组(包括11例卵巢内膜样癌、8例透明细胞癌、2例浆液性囊腺癌及1例黏液性囊腺癌),以同期22例单纯卵巢内异症患者的异位内膜及在位内膜的病理石蜡标本(内异症组)及16例宫颈上皮内瘤变(CIN)Ⅲ患者的正常子宫内膜的病理石蜡标本(对照组)为对照.通过显微切割技术分别获取恶变组患者的恶变组织22份,癌旁异位内膜组织15份及在位内膜组织10份;内异症组患者的异位内膜组织22份及在位内膜组织17份;对照组患者的正常子宫内膜组织16份.通过亚硫酸盐修饰后酶切技术检测各组织中SPOCK2基因甲基化情况,免疫组化SP法检测SPOCK2基因的蛋白表达情况.探讨SPOCK2基因异常甲基化与其蛋白表达的关系.结果 (1)SPOCK2基因甲基化情况:恶变组患者的恶变组织中,SPOCK2基因甲基化发生率为45％(10/22),显著高于癌旁异位内膜组织(1/15),两者比较,差异有统计学意义(P＜0.05);恶变组患者的癌旁内异症组织中SPOCK2基因甲基化发生率(1/15)与内异症组患者的异位内膜(5％,1/22)比较,差异无统计学意义(P＞0.05).(2)SPOCK2基因蛋白表达情况:恶变组患者的恶变组织中SPOCK2基因蛋白表达缺失率为44％(11/22),显著高于恶变组患者癌旁异位内膜组织的2/15,两者比较,差异有统计学意义(P＜0.05);但恶变组患者癌旁异位内膜组织中SPOCK2基因蛋白表达缺失率(2/15)与内异症组异位内膜(5％,1/22)比较,差异无统计学意义(P＞0.05).3组在位内膜组织中SOPCK2基因的蛋白表达缺失率比较,差异无统计学意义(P＞0.05).(3)SPOCK2基因甲基化与其蛋白表达缺失的关系:SPOCK2基因异常甲基化能够导致其蛋白表达缺失( 20/22,P＜0.05).结论 SPOCK2基因的表观失活与卵巢内异症恶变相关.%Objective To investigate epigenetic inactivation of SPOCK2 gene in the malignant transformation of ovarian endometriosis ( EM ) by comparing the methylation status and protein expression of SPOCK2 gene in the malignant tissues,ectopic endometria and the eutopic endometria of endometriosis.Methods From Jan.2005 to Jan.2011,22 paraffin-embedded specimens diagnosed as malignant transformation of ovarian endometriosis ( EAOC ) including 11 cases with ovarian endometrioid carcinoma,8 cases with clear cell carcinoma,2 cases with serous cystadenocarcinoma and 1 case with mucous cystoadenocarcinoma matched with 22 cases with ovarian endometriosis and 16 cases with normal endometrium form cervical intraepithelial neoplasia(CIN) patients as controls in Department of Obstetrics and Gynecology of Shengjing Hospital.Twenty-two malignant tissues,15 ectopic endometria and 10 eutopic endometria were captured by microdissection in EAOC group; 22 eetopic endometria and 17 eutopic endometria were captured in EM group; 22 endometrium were captured in the NE group.The methylation statue of SPOCK2 was determined by combined bisulfite restriction analysis,and the protein expression of SPOCK2 was evaluated by immunohistochemistry.Results ( 1 ) Methylation of SPOCK2:in the EAOC group,the frequency of SPOCK2 hypermethylation in malignant tissue was 45％ (10/22),which was significantly higher than 1/15 in the ectopic endometrium (P＜0.05).There was no statistical difference of the frequency of SPOCK2 hypermethylation in ectopic endometrium in the EAOC group(1/15) and EM group (5％,1/22) (P＞0.05).(2) SPOCK2 protein:the loss rate of SPOCK2 was 44％ (11/22) in malignant tissue in EAOC group,which were significantly higher than 2/15 of in ectopic endometrium of EAOC (P ＜ 0.05).However,there was no remarkable difference in loss rate of SPOCK2 protein between ectopic endeometrium of EAOC and endometrium of EM [ 2/15 vs.5％ ( 1/22 ),P ＞ 0.05 ].No significantly difference in loss rate of SPOCK2 in eutopic endometrium was observed among three groups ( P ＞ 0.05 ).(3) The abnormal methylation of SPOCK2 could lead to loss expression of protein ( P ＜ 0.05 ).Conclusion Epigenetic inactivation of SPOCK2 gene is involved in the malignant transformation of ovarian endometriosis.