PAX1基因甲基化特异性定量PCR检测在宫颈癌筛查中的意义

目的 探讨定量测定配对盒家族基因1（PAX1）甲基化水平在宫颈癌筛查中的意义。方法 收集正常宫颈组织20例、宫颈上皮内瘤变Ⅰ（CINⅠ）组织15例、CINⅡ组织16例、CINⅢ组织19例和宫颈癌组织22例。采用甲基化特异性实时定量聚合酶链反应（QMSP）定量检测不同宫颈组织中PAX1甲基化水平，甲基化特异性PCR（MS-PCR）检测宫颈癌组织PAX1基因区域甲基化情况，并同时行第2代杂交捕获 人乳头瘤病毒 DNA（HC2-HPV-DNA）检测。采用受试者工作特征曲线（ROC）比较两者对宫颈癌的诊断效率。甲基化率通过甲基化指数（PMR）进行指标量化。结果 宫颈癌组织的PMR为（75.27±30.61）％，显著高于CIN Ⅲ的（12.90±10.80）％和其他良性病变及正常组织（P＜0.001）。QMSP 检测PAX1甲基化的ROC曲线下面积（AUC）、灵敏度和特异度分别为0.98、100.0％和84.3％，优于HC2-HPV-DNA检测的0.82、100.0％和52.5％，差异有统计学意义（P＜0.001）。MS-PCR检测结果显示，在癌组织原发灶、转移性癌组织、毗邻原发灶的正常组织和距原发灶边缘＞3cm的正常组织中，PAX1的甲基化率分别为95.0％（19／20）、100.0％（4／4）、70.0％（14／20）和35.0％（7／20），组间比较差异有统计学意义（P＜0.001）。结论 QMSP方法定量检测PAX1的甲基化具有极高的灵敏度，且其特异度超过目前常用的HC2-HPV-DNA检测方法，在临床筛查和宫颈癌的早期诊断中可能具有潜在的应用价值。

Quantitative methylation-specific PCR for PAX1 gene and its significance in detection of cervical cancer

Objective To explore the role of a quantitative measure of the paired boxed gene 1 （PAX1） methylation in detection of cervical cancer. Methods The percentage of PAX1 methylation was detected by real-time quantitative methylation-specific polymerase chain reaction （QMSP） in normal cervical tissues （ n = 20） , cervical intraepithelial neoplasia Ⅰ （ CIN Ⅰ ） tissues （ n = 15 ） , CIN Ⅱ tissues （n = 16）, CIN Ⅲ tissues （n = 19） and cervical cancer tissues （n = 22）. The methylation status of PAX1 gene in cervical cancer tissues was tested by methylation-specific polymerase chain reaction （MS-PCR）. The efficacy of PAX1 in diagnosis of cervical cancer was compared with that of the hybrid capture 2-human papilloma virus-DNA （HC2-HPV-DNA） test by ROC curve. Results The percentage of methylated reference （PMR） in cervical cancer was （75.27±30. 61 ）% , significantly higher than （ 12. 90 ± 10. 80） % in CIN Ⅲ and other milder lesions or normal tissues （P 〈 0. 001 ）. The area under the ROC curve （ AUC）, sensitivity and specificity of PAX1 methylation tested by QMSP was 0. 98, 100. 0% and 84. 3%, better than 0. 82, 100. 0% and 52. 5% of HC2-HPV-DNA test （P 〈 0. 001 ）. The MS-PCR test showed that the methylation rate of PAX1 in cervical cancer, metastatic cancer tissue,adjacent normal tissue and remote normal tissue was 95.0% （19/20）, 100. 0% （4/4）, 70. 0% （14/20） and 35.0% （7/20） with significance（ P 〈 0. 001 ）. Conclusion Quantitative measurement of PAX1 hypermethylation in eervical serapings is highly sensitive and more specific than HC2-HPV-DNA test in detection of cervical cancer. Quantitative measurement of PAX1 methylation may have a potential value for diagnosis of cervical cancer in clinic.