血浆中检测FHIT、p16、MGMT和RASSF1A基因甲基化在肺癌诊断中的价值

Values of promoter hypermethylation of FHIT, p16, MGMT and RASSF1A genes in plasma in the diagnosis of lung cancer

目的:探讨血浆中脆性组氨酸三连体基因(fragile histidine triad,FHIT)、p16基因、O6-甲基鸟嘌呤-DNA甲基转移酶基因(O6-methyl-guanine-DNA methyltransferase,MGMT)及信号转导通路基因(rasassociation domain family1A,RASSF1A)等抑癌基因启动子异常甲基化及其联合检测在肺癌筛查及早期诊断中的价值。方法:采用甲基化特异性PCR(methylation specifi c PCR,MSP)法,检测53例肺癌组织和对应的血浆标本以及24例肺良性病变组织中FHIT、p16、MGMT和RASSF1A4种基因启动子区甲基化状态。结果:肺癌组织中FHIT、p16、MGMT和RASSF1A基因启动子区甲基化检出率分别为39.6%(21/53)、49.1%(26/53)、35.8%(19/53)和18.9%(10/53);其对应的血浆标本中这4个基因的甲基化检出率分别为35.8%(19/53)、49.1%(26/53)、28.3%(15/53)和17.0%(9/53),两组标本甲基化检出率存在着较好的一致性(P>0.05)。24例肺良性病变组织标本和血浆标本中分别有同1例(0.04%)出现p16基因甲基化,与肺癌组比较差异有统计学意义(P<0.05)。4项指标联合检测可显著提高肺癌检测的敏感度(73.6%)和特异度(95.8%)。p16基因在血浆中甲基化检出率与患者吸烟指数有明显相关性(P<0.05)。结论:血浆中多个肺癌相关基因甲基化联合检测有望成为肺癌筛查、早期诊断简便有效的指标。

Objective： To investigate the values of detection of promoter methylation status of cancer suppressor genes such as fragile histidine triad （FHIT）, p16, O6-methyl-guanine-DNA methyltransferase （MGMT） and Ras association domain family 1A （RASSF1A） genes in plasma or their combined detection in the screening and early diagnosis of lung cancer. Methods： The methylation-specific PCR （MSP） method was used to detect the promoter methylation status of FHIT, p16, MGMT and RASSF1A genes in lung cancer tissues and plasma from 53 cases and lung benign tissues from 24 cases. Results： The positive rates of promoter methylation of FHIT, p16, MGMT and RASSF1A genes in lung cancer tissues were 39.6% （21/53）, 49.1% （26/53）, 35.8% （19/53） and 18.9% （10/53）, respectively; and the positive rates in the corresponding plasma were 35.8% （19/53）, 49.1% （26/53）, 28.3% （15/53）, and 17.0% （9/53）, respectively. The positive rates of promoter methylation in the two samples were coincident （P0.05）. The promoter methylation of p16 gene was seen both in plasma and lung benign tissue from one of 24 cases （0.04%）. There was a significant difference between the lung cancer group and lung benign lesion group （P0.05）. Combined detection of promoter methylation of FHIT, p16, MGMT and RASSF1A genes in plasma could increase the sensitivity （73.6%） and specificity Values of promoter hypermethylation of FHIT, p16, MGMT and RASSF1A genes in plasma in the diagnosis of lung cancer KANG Chun-yan1, ZHOU Hui-cong2, TANG Shao-peng3, XIAO Hong1 1. Department of Pathology, Henan Medical College for Staff and Workers, Zhengzhou 451191, China; 2. Department of Gastroenterology, First Affiliated Hospital of Xinxiang Medical College, Weihui 453100, China; 3. Thoracic Surgery, Henan Chest Hospital, Zhengzhou 450003, China Abstract Objective： To investigate the values of detection of promoter methylation status of cancer suppressor genes such as fragile histidine triad （FHIT）, p16, O6-methyl-guanine-DNA methyltransferase （MGMT） and Ras association domain family 1A （RASSF1A） genes in plasma or their combined detection in the screening and early diagnosis of lung cancer. Methods： The methylation-specific PCR （MSP） method was used to detect the promoter methylation status of FHIT, p16, MGMT and RASSF1A genes in lung cancer tissues and plasma from 53 cases and lung benign tissues from 24 cases. Results： The positive rates of promoter methylation of FHIT, p16, MGMT and RASSF1A genes in lung cancer tissues were 39.6% （21/53）, 49.1% （26/53）, 35.8% （19/53） and 18.9% （10/53）, respectively; and the positive rates in the corresponding plasma were 35.8% （19/53）, 49.1% （26/53）, 28.3% （15/53）, and 17.0% （9/53）, respectively. The positive rates of promoter methylation in the two samples were coincident （P0.05）. The promoter methylation of p16 gene was seen both in plasma and lung benign tissue from one of 24 cases （0.04%）. There was a significant difference between the lung cancer group and lung benign lesion group （P0.05）. Combined detection of promoter methylation of FHIT, p16, MGMT and RASSF1A genes in plasma could increase the sensitivity （73.6%） and specificity （95.8%） in the diagnosis of lung cancer. The positive rate of promoter methylation of p16 in plasma was significantly correlated with smoking index （P0.05）. Conclusion： Joint detection of promoter methylation of lung cancer-related genes in plasma may become a feasible and effective index in the screening and early diagnosis of lung cancer.