人端粒酶RNA基因检测在子宫颈病变筛查中的意义

目的 探讨人端粒酶RNA(hTERC)基因检测在宫颈病变筛查中的意义.方法 选择经宫颈液基细胞学检查为正常一高度鳞状上皮内瘤变(HSIL)的301例患者为研究对象,采用人乳头状瘤病毒(HPV)杂交捕获2代(HC2)方法检测其高危型HPV感染状况,病理学检查明确其病变性质,荧光原位杂交(visa)技术检测其hTERC基因异常扩增情况.以病理学结果为金标准,将FISH技术检测结果与液基细胞学和HC2方法检测结果进行比较.结果 301例患者中,宫颈液基细胞学检查为正常、不典型鳞状细胞(ASC)、低度鳞状上皮内瘤变(LSIL)与HSIL细胞中,hTERC基因异常扩增率分别为3.0%(6/203)、21.2%(14/66)、44.4%(8/18)和92.9%(13/14),两两比较,差异均有统计学意义(P<0.05～0.01).有病理检查结果的98例患者中,炎症或湿疣、宫颈上皮内瘤变(CIN)Ⅰ、CIN Ⅱ、CIN Ⅲ和浸润癌患者的hTERC基因异常扩增率分别为4.4%(2/45)、20.0%(4/20)、6/8、86.7%(13/15)和100.0%(10/10),炎症或湿疣、CIN Ⅰ细胞中hTERC基因异常扩增率明显低于其他病变(P<0.01).23例高级别CIN(即CINⅡ～Ⅲ)患者中,FISH技术检测为hTERC基因异常扩增阳性19例(82.6%,19/23),液基细胞学检查为HSIL者仅4例(17.4%,4/23),FISH技术检测筛出高级别CIN的敏感度明显高于液基细胞学检查(P<0.01).高危型HPV DNA感染率,CIN Ⅰ患者为75.0%,高级别CIN和浸润癌患者均为100.0%.hTERC基因异常扩增检出高级别CIN和浸润癌的敏感度分别为82.6%和100.0%,分别与高危型HPV DNA检测检出高级别CIN和浸润癌的敏感度(均为100.0%)比较,差异均无统计学意义(P>0.05);而特异度前者明显高于后者(分别为67.8%～73.5%和25.6%～27.7%,P<0.01).FISH技术检测结果显示,CIN Ⅰ细胞中hTERC基因异常扩增信号为2:3型者占84.9%,2:4型占15.1%,4:4型为0;CIN Ⅱ～Ⅲ细胞中异常扩增信号为2:3、2:4和4:4型者分别占44.6%、24.8%和17.8%,与CIN Ⅰ比较,2:3型比例明显下降(P<0.01),2:4型比例呈上升趋势(P>0.05),4:4型比例明显升高(P<0.01).结论 应用FISH技术检测hTERC基因异常扩增情况可辅助液基细胞学检查和HPV HC2方法诊断高级别CIN;且hTERC基因异常扩增信号为2:4和4:4型以上可能是进展为高级别CIN的预测指标.

Evaluation of genomic amplification of the human telomerase RNA component gene in the screening of cervical lesions

Objective To investigate the genomic amplification of the human telomerase RNA component (hTERC) gene in cervical cytology and evaluate its role in screening of cervical lesions. Methods A total of 301 cases were recruited, with liquid-based cytology diaghoses as normal (n=203), atypical squamous cells (ASC, n=66), low-grade squamous intraepithelial lesions ( LSIL,n=18), and high-grade squamous intraepithelial lesions ( HSIL, n=14). Following cytological examination, the slides were analyzed using a two-color fluorescence in aitu hybridization ( FISH ) probe targeted to chromosome 3q26 containing hTERC. The hTERC findings were compared to the cytologic and histologie results, as well as high-risk human papilloma viruses (HPV) results. Results Genomie amplification of hTERC was found in 3.0% (6/203)of normal specimens, 21.2% (14/66) of ASC, 44.4% (8/18) of LSIL and 92.9% (13/14) of HSIL, with a significant difference in each pair wise (all P<0.05). Significantly more cells with 3q26 gain were found in cervical intraepithelial lesion (CIN) Ⅱ than in CIN Ⅰ(75.0% vs. 20.0% ), as well as in CIN Ⅲ (86.7% vs. 20.0% ) and squamous cervical cancer (SCC) than in CIN Ⅰ (100.0% vs. 20.0%) ( all P<0.01). The sensitivity of hTERC amplification was significantly higher than cytological screening (82.6% vs. 17.4%, P<0.01), and its specificity was higher than high-risk HPV test (67.8%-73.5% vs. 25.6%-27.7%, P<0.01) in the diagnosis of HSIL (CIN Ⅱ - Ⅲ). The abnormal hTERC signal type mostly was 2:3 in CIN Ⅰ (84.9% ) ; whereas in CIN Ⅱ-Ⅲ, 2: 3, 2:4 and 4:4 accounted for 44.6%, 24.8% and 17.8%, respectively. Conclusion Testing the gain of chromosome 3q26 in cytological specimens using specific probe for hTERC is powerful in screening of HSIL, and the amplification patterns of 2:4 and 4:4 may serve as potential prognosis markers.