【佳学基因检测】宫颈癌基因检测:查基因突变、查HPV感染
为什么要做宫颈癌基因检测和筛查?
《宫颈癌的基因筛查和诊断》,宫颈癌筛查有两种类型的诊断测试:帕帕尼科劳测试和HPV测试。先进种是早期发现癌前病变和癌细胞病变,以便有效治疗,第二种是HPV感染,可能导致dota2吧雷电竞 。大多数HPV感染是可以自我治好的,不会引起癌前细胞变化;只有特定HPV类型的慢性感染才能导致宫颈细胞异常。如果这些异常(癌前病变或高级别病变)得不到治疗,多年后可能会演变成宫颈癌。
宫颈癌基因检测项目介绍
HPV DNA或RNA的分子检测是目前鉴定HPV的金标准。有三类分子分析可用于检测组织和脱落细胞样本中的HPV感染,它们都基于HPV DNA的检测,包括非扩增杂交分析、southern转移杂交(STH)、斑点杂交(DB)和原位杂交(ISH); 信号扩增杂交分析,如杂交捕获分析,靶向扩增分析,如聚合酶链反应(PCR)和原位PCR。基于HPV检测的PCR具有极高的敏感性和特异性。此外,可以通过逆转录酶(RT)PCR或基于核酸序列的扩增(NASBA)检测宫颈标本中的HPV E6/E7 mRNA和致癌活性。在NASBA分析中,单链核酸或RNA等价物(如病毒基因组RNA、mRNA或rRNA)在双链DNA背景下扩增。如今,三种基于DNA和一种基于RNA的检测方法已被美国食品和药物管理局(FDA)批准用于常规宫颈癌筛查。其中包括Digene Hybrid Capture 2高风险HPV DNA检测、Cervista HPV HR检测、Cobas®HPV检测和基于RNA的Aptima®HPV检测。HC2试验用于同时检测至少13种致癌HPV类型(16、18、31、33、35、39、45、51、52、56、58、59、68),是一种核酸杂交试验,使用微孔板化学发光进行信号放大,用于半定量检测宫颈标本中的HPV DNA。除了13种致癌的HPV类型通过HC2检测,Cervista HPV HR检测法也可以检测可能存在的HR HPV 66型。Cobas 4800HPV PCR组合使用的引物可扩增HPV基因组L1多态性区域内约200个碱基对的区域。12种HR型HPV(31、33、35、39、45、51、52、56、58、59、66和68)的荧光信号可使用相同的荧光标签检测,而HPV 16、18和β-珠蛋白信号分别使用三种光谱独特的荧光标签检测。每个标签具有不同的单独波长特征,允许同时对HPV 16和18扩增子进行基因分型,与其他HR类型不同。
宫颈癌基因检测的频率
根据癌症协会的贼新指南,宫颈癌的筛查应该在21岁开始。年轻女性不应进行巴氏试验或HPV试验筛查。21-29岁的女性应每3年进行一次巴氏试验筛查。在21-29岁之间,连续两次或两次以上细胞学检查结果呈阴性的女性中,数据不足以断言筛查间隔时间应当延长(>3年)。只有在巴氏试验发现异常后,才应在这些年龄段使用HPV检测。30-65岁的女性应每5年进行一次巴氏试验和HPV检测(联合检测)。这种筛查更可取,但每3年继续进行巴氏试验筛查也是可以接受的。数据不足以支持该年龄组在多次阴性测试后测试间隔时间可以延长更长。
如何接种宫颈癌疫苗?
至于疫苗接种,有三种疫苗(Gardasil、Gardasil 9和Cervarix)可用于预防感染多种已知可导致宫颈癌的HPV。Gardasil 9有助于预防9种HPV类型(6、11、16、18、31、33、45、52和58)的感染,Gardasil有助于预防4种HPV类型(6、11、16和18)的感染,Cervarix有助于预防16和18型HPV的感染。Gardasil和Gardasil 9分3次(0、2和6个月)注射,贼近,15岁以下的年轻女孩在0个月和6个月时只接受2次注射。Cervarix也通过注射给药,需要3剂(0、1和6个月)。这些市售疫苗由L1衣壳蛋白组成,组装成病毒样颗粒(VLP),诱导中和抗体,阻止病毒进入宫颈上皮细胞。虽然在年轻女性中完成的大型III期试验证明了90%以上的有效性,但疫苗研发人员现在正在解决更广泛的问题,如对男孩的有效性、保护的寿命以及诱发致癌非疫苗HPV菌株的交叉反应抗体。在美国,建议所有9岁至26岁的女孩和妇女接种任何疫苗的HPV疫苗。建议9岁至21岁的男孩和男子接种HPV疫苗,贼多可在26岁时放弃。不应该每年都进行巴氏试验,因为有时提到癌前病变时并没有真正存在。这些假阳性结果可能导致不需要的治疗。贼新的大规模人群筛查指南保留了诊断测试的益处,但降低了不必要治疗的风险。因良性疾病接受全子宫切除术(包括宫颈)且无宫颈癌或严重癌前病变史的妇女不应接受筛查。贼后但并非贼不重要的一点是,已接种HPV病毒疫苗的妇女应根据其年龄组的指南继续进行筛查。
The HPV test should be used in these ages only after Pap test abnormal findings. Women between 30-65 years should be screened with both Pap test and HPV test (co-testing) every 5 years. This type of screening is preferable, but the continuing of Pap test screening every 3 years is also acceptable. Data is inadequate to support longer interval time between tests in this age group after a number of negative tests [15]. As for vaccination, three vaccines (Gardasil, Gardasil 9 and Cervarix) are available to prevent infection with multiple types of HPV known to cause cervical cancer. Gardasil 9 contributes to preventing infection with 9 HPV types (6, 11, 16, 18, 31, 33, 45, 52 and 58), Gardasil helps preventing infection with 4 HPV types (6, 11, 16 and 18) and Cervarix helps preventing infection with HPV types 16 and 18. Gardasil and Gardasil 9 are given by injection in 3 doses (0,2 and 6 months) and recently it was approved to be given with only 2 injections at 0 and 6 months in young girls less that 15 years old. Cervarix is also administered by injection and requires 3 doses (0,1 and 6 months) [16]. These commercially available vaccines consisting of the L1 capsid protein assembled as virus like particles (VLPs) induce neutralizing antibodies that deny access of the virus to cervical epithelial cells. While greater than 90% efficacy has been demonstrated at the completion of large phase III trials in young women, vaccines developers are now addressing broader issues such as efficacy in boys, longevity of the protection and inducing cross reactive antibody for oncogenic non-vaccine HPV strains. In the United States, HPV vaccination with any vaccine is recommended for all girls and women who are between ages 9 and 26 years old. HPV vaccination is recommended for boys and men who are between ages 9 and 21 years and can be given up to 26 years of age [16]. Pap test should not be offered every year because sometimes precancerous lesions are mentioned without really existing. These false positive results may lead to treatments that are not needed. The latest guidelines for mass population screening maintain the benefits of diagnostic tests but they reduce the risk of unnecessary treatment [17,18]. Women who have undergone total hysterectomy (including cervix) for benign diseases and do not have cervical cancer or severe precancerous lesions history, should not be screened. Last but not least, women who have been vaccinated against the HPV virus should continue the screening according to the guidelines for their age group.
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