A higher degree of methylation of the HPV 16 E6 gene is associated with a lower likelihood of being diagnosed with cervical intraepithelial neoplasia

BACKGROUND:

Although HPV 16 is the most common HPV genotype associated with cancerous lesions of the cervix, only a fraction of HPV 16 infected women are diagnosed with precancerous lesions of the cervix. Therefore, molecular changes in HPV 16, rather than infections per se, may serve as better screening or diagnostic biomarkers. The purpose of the study was to evaluate whether methylation status of specific regions of the HPV E6 gene promoter and enhancer is independently associated with the likelihood of being diagnosed with higher grades of cervical intraepithelial neoplasia (CIN 2+).

METHODS:

The study included 75 HPV 16‐positive women diagnosed with CIN 2+ or ≤CIN 1. Pyrosequencing technology was applied to quantify methylation at 6 cytosine guanine dinucleotide (CpG) sites of the HPV 16 E6 promoter and enhancer. CIN 2+ (yes/no) was the dependent variable in logistic regression models that specified the degree of methylation of the CpG sites of the HPV 16 E6 gene as the primary independent predictors. All models were adjusted for demographic, lifestyle, known risk factors for cervical cancer, and circulating concentrations of “cancer‐protective” micronutrients.

RESULTS:

The odds of being diagnosed with CIN 2+ were 79% lower when the degree of methylation of the HPV 16 enhancer and promoter sites was ≥9.5% (OR = 0.21; 95% CI, 0.06‐0.79; P = .02).

CONCLUSIONS:

Results suggested that CpG methylation is independently involved in the biology of HPV 16 as well as in the development of higher grades of CIN. Cancer 2011. © 2010 American Cancer Society.     

HPV16 L1 and L2 DNA methylation predicts high‐grade cervical intraepithelial neoplasia in women with mildly abnormal cervical cytology

DNA methylation changes in human papillomavirus type 16 (HPV16) DNA are common and might be important for identifying women at increased risk of cervical cancer. Using recently published data from Costa Rica we developed a classification score to differentiate women with cervical intraepithelial neoplasia grade 2 or 3 (CIN2/3) from those with no evident high‐grade lesions. Here, we aim to investigate the performance of the score using data from the UK. Exfoliated cervical cells at baseline and 6‐months follow‐up were analyzed in 84 women selected from a randomized clinical trial of women undergoing surveillance for low‐grade cytology. Selection of women for the methylation study was based on detectable HPV16 in the baseline sample. Purified DNA was bisulfite converted, amplified and pyrosequenced at selected CpG sites in the viral genome (URR, E6, L1 and L2), with blinding of laboratory personnel to the clinical data. The primary measure was a predefined score combining the mean methylation in L1 and any methylation in L2. At the second follow‐up visit, 73/84 (87%) women were HPV16 positive and of these 25 had a histopathological diagnosis of CIN2/3. The score was significantly associated with CIN2/3 (area under curve = 0.74, p = 0.002). For a cutoff with 92% sensitivity, colposcopy could have been avoided in 40% (95% CI 27–54%) of HPV16 positive women without CIN2/3; positive predictive value was 44% (32–58%) and negative predictive value was 90% (71–97%). We conclude that quantitative DNA methylation assays could help to improve triage among HPV16 positive women.     

Low risk of type-specific carcinogenic HPV re-appearance with subsequent cervical intraepithelial neoplasia grade 2/3

Carcinogenic human papillomavirus (HPV) infections are very common after sexual debut and nearly all become undetectable ("clear") within a few years. Following clearance, the long-term risks of type-specific HPV re-appearance and subsequent risk of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) are not well defined. In the 7-year, population-based cohort study in Guanacaste, Costa Rica, we studied how often type-specific carcinogenic HPV infections re-appeared after clearance and how often re-appearance led to CIN2+. We considered 1,740 carcinogenic HPV infections detected by MY09/11 PCR among 2,805 women (18-91 years old, median 34) who were actively followed at 6- or 12-month intervals. We identified women with one or more type-specific HPV infections that cleared and re-appeared and further defined a subgroup of "definite clearance and re-appearance" (≥2 intervening negative results over a period of ≥1 year). We determined the absolute risk of CIN2+ among the different groups. p values are two-sided. Only 7.7% (81/1,052) of HPV-infected women had intervening negative results. Very few (3.7%, 39/1,052) had "definite clearance and re-appearance", of which 5.1% (2/39) subsequently persisted to a diagnosis of CIN2. There were zero CIN3+ lesions. Extremely few women (2/2,805 of women in our cohort) had a type-specific carcinogenic HPV infection clear, re-appear and lead to CIN2+. If confirmed, this argues against vaccination to avoid re-appearance that leads to precursor lesions and against the need of frequent HPV screening after initial negative results.     

Heterogeneity of high‐grade cervical intraepithelial neoplasia related to HPV16: Implications for natural history and management

Factors associated with progression from cervical intraepithelial neoplasia (CIN) grades 2 and 3 to invasive cancer are not well understood; most CIN2 and CIN3 do not progress to cancer. Among carcinogenic human papillomavirus (HPV) types, infections with HPV16 have the highest risk of progressing to cancer. We evaluated the heterogeneity of risk factors, lesion size, colposcopic impression and colposcopic biopsy results in relation to HPV16 status among 627 women with CIN2 or CIN3 in women referred to colposcopy at the University of Oklahoma. Loop excision specimens were evaluated in 12 radial segments to estimate lesion size. The mean age at CIN3 was 27.7 years for HPV16‐positive women (n = 225) and 33.6 years for HPV16‐negative women (n = 104). The average lesion size did not differ by HPV16 status (p = 0.83). Among HPV16‐positive women with CIN3, lesions were significantly larger in women 30 years and older (p = 0.03). Colposcopic impression was worse in women with HPV16 infections (p = 0.009), but the detection of CIN3 at the preceding biopsy was not improved in HPV16‐positive women. CIN3 is detected at the same lesion size, but at much younger age in women with HPV16 infections, suggesting faster growth. CIN2 lesion size in women without HPV16 peaks below 30 years and then decreases, suggesting frequent regression, whereas HPV16‐related CIN2 is more likely to persist. Lesion size seems to be an important determinant of colposcopy and biopsy performance. Genotyping for HPV16 in cervical cancer screening can improve risk stratification but may pose challenges to finding small lesions in colposcopy.     

Prevalence of types 16 and 33 is increased in high-risk human papillomavirus positive women with cervical intraepithelial neoplasia grade 2 or worse

High-risk human papillomavirus (hrHPV) types are causally related to cervical cancer and its high-grade precursor lesions. The risk posed by the different hrHPV types for the development of cervical intraepithelial neoplasia grade 2 or worse (> or =CIN2) needs to be established. Here, we present the hrHPV type-distribution in relation to cytology and histology for women participating in a cervical screening program. From 44,102 women who participated in a population-based cervical screening program in the Netherlands, 2,154 hrHPV GP5+/6+ PCR positive women were recruited to determine the distribution of 14 hrHPV types by reverse line blotting of GP5+/6+ PCR products. For each HPV type, associations with cytology and histologically confirmed > or =CIN2 were measured by odds ratios. HPV types 16 and 33 were more prevalent in women, amongst those containing a single hrHPV type, with moderate dyskaryosis or worse (>BMD) than in women with normal cytology, but only in case of underlying > or =CIN2 (OR 4.10, 95%CI 2.98-5.64 and OR 2.68, 95%CI 1.39-5.15, respectively). Similar results were obtained for women with double infections (OR 3.29, 95% CI 1.61-6.75 and OR 4.37, 95% CI 1.17-16.34). Coexisting types did not influence the prevalence of > or =CIN2 in HPV 16 or 33 positive women. The increased prevalence of type 16 and 33 in hrHPV positive women with > or =CIN2, compared to women with normal cytology, suggests that infection with these types confers an increased risk for development of > or =CIN2. Distinguishing these types may therefore have implications for future cervical screening strategies.     

Human papillomavirus (HPV) type 16-specific CD8+ T cell responses in women with high grade vulvar intraepithelial neoplasia

Human papillomavirus (HPV)-associated vulvar intraepithelial neoplasia (VIN) has serious sequelae for the sufferer. Current treatments are associated with poor response and high relapse rates. The development of HPV-specific T cell immunotherapies offers a new approach to treatment. This will require a detailed understanding of the spectrum of T cell responses induced by HPV antigens, and how effectively viral antigens can be accessed by the immune system. We have investigated the frequency and spectrum of HPV16-specific CD8+ T cell responses to three HPV16 antigens in 9 women with high grade VIN (VIN3). CD4-depleted populations of responder cells were screened against overlapping 30-35mer peptides covering the sequences of HPV16 E6, E7 and E4 using ELISPOT assays of IFN-gamma release. We demonstrated CD8+ T cell reactivity to one or more of the proteins in 6 of 9 patient samples. All 6 of these responders recognised peptides covering the E7 protein, 3 of 9 women responded to E6 peptides, but no reactivity was seen to E4. Our results suggest that HPV16-specific cytotoxic T cells (CTLs) are relatively common in women with persistent VIN3. The HPV-specific CTL response, however, seems to be ineffective. There is some evidence that there are problems associated with the processing and presentation of HPV antigens by the infected vulvar epithelium. It will be crucial to address this in the design of any T cell based therapy for HPV-associated VIN and vulval cancer.     

宫颈上皮内瘤变与宫颈癌中DNA甲基化状态的研究

DNA甲基化与肿瘤发生发展关系的研究越来越受到重视,目前大量研究发现多种基因的异常甲基化与官颈上皮内瘤变及宫颈癌相关.     

Human papillomavirus 16 in breast cancer of women treated for high grade cervical intraepithelial neoplasia (CIN III).

Women with both a history of high grade cervical intraepithelial neoplasia (CIN III) and breast carcinoma as second primary cancer were selected for studying the presence of HPV in breast carcinomas. Paraffin embedded material from 38 patients with 41 breast carcinoma cases after CIN III were examined by polymerase chain reaction (PCR) and in situ hybridization. By PCR we detected HPV 16 DNA in 19 out of 41 cases (46%) of the breast carcinomas. One case proved to be HPV 16 positive also by in situ hybridization. HPV 16 was also detected in 32 out of the 38 patients with CIN III (84%). All HPV 16 positive breast carcinomas were HPV 16 positive in their corresponding CIN III lesions. Eight patients with diagnosed breast cancer before the CIN III lesions were used as controls. None of these had HPV positive breast carcinomas. No cases were positive for HPV 11, 18, or 33. HPV 16 was detected in the primary tumours, in local metastases from HPV 16 positive tumours, in a distant HPV 16 positive breast carcinoma metastasis to the colon, and in other primary cancers in patients with HPV 16 positive breast carcinomas and HPV 16 positive CIN III. Estrogen and progesterone receptors were quantified in the HPV positive and HPV negative breast carcinomas, and there was no significant difference in the fraction positive in the two groups. Oncogenic HPV DNA might be transported from an original site of infection to other organs by blood or lymph, and possibly be a factor in the development of cancer in different organs.     

宫颈癌和宫颈上皮内瘤变中表皮生长因子受体表达与人乳头瘤病毒16和(或)18感染及其相互关系

目的探讨宫颈癌发生发展过程中,表皮生长因子受体(EGFR)与人乳头瘤病毒(HPV)的作用及其相互关系。方法宫颈癌组60例,选自1997年至2001年间中山大学肿瘤防治中心住院初治的宫颈癌病例,临床分期Ⅰa～Ⅱb期;宫颈上皮内瘤变(CIN)组40例;正常上皮对照组30例。以免疫组化S-P法检测宫颈组织EGFR的表达,以PCR检测HPV16和(或)HPV18感染。结果正常上皮组、CIN组和宫颈癌组的EGFR中强表达率呈梯度上升,分别为0、42.5%和76.7%,差异有统计学意义(P<0.05)。正常上皮组、CIN组和宫颈癌组的HPV16和(或)HPV18感染率分别为6.7%、67.5%和58.3%,宫颈癌组和CIN组的感染率均显著高于正常上皮组(P=0.000),但宫颈癌组与CIN组之间,差异无统计学意义(P=0.355)。肿瘤侵袭程度超过宫颈1/2间质者,EGFR中强表达率显著高于未达1/2间质者(89.2%:56.5%,P=0.004)。宫颈管侵袭者HPV16和(或)HPV18感染率显著高于无侵袭者(88.2%:46.5%,P=0.003)。EGFR与HPV之间无显著相关性(P>0.05)。EGFR与HPV均未显示与宫颈癌预后有关。结论EGFR和HPV与宫颈癌的发生发展有关;EGFR、HPV16和(或)HPV18与宫颈癌预后无关,EGFR与HPV16和(或)HPV18无显著相关性。     

Expression of the p16INK4a and Ki-67 in relation to the grade of cervical intraepithelial neoplasia and high-risk human papillomavirus infection

Objective

The purposes of this study were to evaluate the expression of p16^INK4a (referred as to p16) and Ki-67 in cervical intraepithelial neoplasia (CIN), and the correlation between high-risk human papillomavirus (HPV) infection and the above biomarkers.

Methods

We analyzed 31 patients who were diagnosed with CIN at Kwandong University Myongji Hospital from October 2006 to September 2007. CIN specimens (CIN1, 12; CIN2, 6; CIN3, 13) were obtained by colposcopy-directed biopsy (CDB) or loop electrical excision procedure (LEEP). The expressions of p16 and Ki-67 were evaluated by immunohistochemical methods with antibodies to p16 and Ki67. The immunohistochemical staining results were classified into four grades: 0, 1, 2 and 3. HPV genotyping or Hybrid Capture-II test was used to detect high-risk HPV.

Results

The expression of p16 (p<0.001) and Ki-67 (p=0.003) were positively associated with CIN grade. p16 expressions increased significantly with high-risk HPV infection (p=0.014), especially HPV type 16 and 58. Ki-67 expression was not related with high-risk HPV. There was positive correlation between the expression of the p16 and Ki-67 (p=0.007).

Conclusion

CIN grade were positively related to the expression of p16 and Ki-67. p16 expressions of high-risk HPV specimens significantly increased more than Ki-67. Therefore, in the diagnosis of CIN and high-risk HPV infection, p16 can be a useful biomarker.     

Molecular mapping of high-grade cervical intraepithelial neoplasia shows etiological dominance of HPV16

Women with high-grade cervical intraepithelial neoplasia (HGCIN) frequently present with multiple cervical lesions and multiple concomitant Human papillomavirus (HPV) genotype infections. To elucidate HPV genotype attribution in different regions on the cervix, we performed molecular mapping of cervical disease in women with HGCIN. Thirteen subjects referred to colposcopy for abnormal cervical cancer screening results were included. A cervical smear and biopsies from 4 different areas on the cervix were collected. HPV genotyping using Linear Array (for cytology) or SPF(10) LiPA(25) (for histology) were performed in 13 smears, 52 whole sections from biopsies and 138 tissue regions isolated with laser capture microdissection (LCM). Twelve subjects had a diagnosis of CIN3 and one subject had a diagnosis of CIN2 based on the worst histology found in 4 biopsies. Eight of the 13 smears (62%) showed multiple genotype infections. Four of 13 women (31%) had multiple HPV infections in their biopsies. After performing LCM-PCR, only one woman (8%) had two different carcinogenic HPV types in morphologically distinct, but colliding HGCIN lesions. HPV16 was identified as the causal type in all women with HPV16 in cytology. A large proportion of other HPV types found in cervical smears were not detected at the tissue level. Using tissue-based genotyping and LCM-PCR analysis, we were able to attribute an individual HPV type to each area of CIN lesions. We demonstrate that HPV16 is even more etiologically dominant than previously thought, based on various genotype attribution models.     

Methylation of viral and host genes and severity of cervical lesions associated with human papillomavirus type 16

Methylation of human papillomavirus (HPV) and host genes may predict cervical cancer risk. We examined the methylation status of selected sites in HPV16 and human genes in DNA extracted from exfoliated cervical cell samples of 244 women harboring HPV16‐positive cancer or cervical intraepithelial neoplasia (CIN) or negative for intraepithelial lesions or malignancy (NILM). We quantified the methylation of CpG sites in the HPV16 L1 gene (CpG 6367 and 6389) and in the human genes EPB41L3 (CpG 438, 427, 425) and LMX1 (CpG 260, 262, 266, 274) following bisulfite treatment and pyrosequencing. Receiver operating characteristic (ROC) curves were used to analyze the diagnostic utility of methylation level for the different sites and for a joint predictor score. Methylation in all sites significantly increased with lesion severity (p < 0.0001). Area under the curve (AUC) was highest among the CIN2/3 vs. cancer ranging from 0.786 to 0.853 among the different sites. Site‐specific methylation levels strongly discriminated CIN2/3 from NILM/CIN1 and cancer from CIN2/3 (range of odds ratios [OR]: 3.69–12.76, range of lower 95% confidence bounds: 1.03–4.01). When methylation levels were mutually adjusted for each other EPB41L3 was the only independent predictor of CIN2/3 vs. NILM/CIN1 contrasts (OR = 9.94, 95%CI: 2.46–40.27). High methylation levels of viral and host genes are common among precancerous and cancer lesions and can serve as independent risk biomarkers. Methylation of host genes LMX1 and EPB41L3 and of the viral HPV16 L1 sites has the potential to distinguish among precancerous lesions and to distinguish the latter from invasive disease.     

子宫颈上皮内瘤样病变和子宫颈癌组织中Smad2/3和HPV16 E7的表达及意义

背景与目的:Smads蛋白是转化生长因子-β(transforming growth factor-β,TGF-β)超家族信号转导的下游信号蛋白,与多种肿瘤的发生密切相关;人乳头状瘤病毒(human papillomavirus,HPV)感染是宫颈癌的重要致癌因素,但目前对两者在宫颈癌发病过程中相互关系的研究尚不充分.本研究拟检测不同宫颈病变组织中Smad2/3和HPV16 E7蛋白的表达,探讨HPV感染和Smad2/3蛋白变化在宫颈癌形成和演进进程中的相互关系.方法:采用免疫组织化学SP法检测20例宫颈慢性炎症、30例宫颈上皮内瘤样病变(cervical intraepithelial neoplasia,CIN)和30例宫颈癌组织中Smad2/3和HPV16 E7的表达情况,比较其在各种病变中表达水平的差异.结果:Smad2/3蛋白在慢性宫颈炎、CIN和宫颈癌组织中的阳性率分别为50.0%、73.3%和93.3%,宫颈癌组分别与慢性宫颈炎组和CIN组比较,差异有统计学意义(P＜0.05),慢性宫颈炎组与CIN Ⅲ级组相比,差异有统计学意义(P＜0.05).HPV16 E7蛋白阳性率在慢性宫颈炎、CIN和宫颈癌组织中分别为60.0%、66.7%和83.3%,各组间两两比较差异无统计学意义(P＞0.05).Smad2/3阳性率与宫颈癌临床分期、病理类型、组织学分级和淋巴结转移无关(P＞0.05).Smad2/3与HPV16 E7表达呈正相关(r=0.271,P=0.015).结论:Smad2/3蛋白在宫颈癌组织中表达升高,可能在宫颈癌的发生过程中起重要作用;HPV感染与Smad2/3蛋白在宫颈癌组织中表达升高密切相关.     

HPV16 methyl‐haplotypes determined by a novel next‐generation sequencing method are associated with cervical precancer

We have developed and evaluated a next‐generation bisulfite sequencing (NGS) assay to distinguish HPV16 cervical precancer (CIN2–3; N =59) from HPV16‐positive transient infections (N = 40). Cervical DNA was isolated and treated with bisulfite and HPV16 methylation was quantified by (i) amplification with barcoded primers and massively parallel single molecule sequencing and (ii) site‐specific pyrosequencing. Assays were evaluated for agreement using intraclass correlation coefficients (ICC). Odds ratios (OR) for high methylation vs. low methylation were calculated. Single site pyrosequencing and NGS data were correlated (ICC = 0.61) and both indicated hypermethylation was associated with precancer (ORs of 2–37). Concordant NGS and pyrosequencing results yieled ORs that were stronger when compared with using either assay separately. Within the L1 region, the ORs for CIN2–3 were 14.3 and 22.4 using pyrosequencing and NGS assays, respectively; when both methods agreed the OR was 153. NGS assays provide methylation haplotypes, termed methyl‐haplotypes from single molecule reads: cases had increased methyl‐haplotypes with ≥ 1 methylated CpG site(s) per fragment compared with controls, particularly in L1 (p = 3.0 × 10^?8). The maximum discrimination of cases from controls for a L1 methyl‐haplotype had an AUC of 0.89 corresponding to a sensitivity of 92.5% and a specificity of 73.1%. The strengthening of the OR when the two assays were concordant suggests the true association of CpG methylation with precancer is stronger than with either assay. As cervical cancer prevention moves to DNA testing methods, DNA based biomarkers, such as HPV methylation could serve as a reflex strategy to identify women at high risk for cervix cancer.     

p16INK4a immunohistochemistry is a promising biomarker to predict the outcome of low grade cervical intraepithelial neoplasia: comparison study with HPV genotyping

Objective

In cervical intraepithelial neoplasia (CIN), p16^INK4a immunohistochemistry has been reported to be a useful diagnostic biomarker. However, limited information is available about the association between the p16^INK4a immunohistochemistry and the outcomes of CIN. Here, we report p16^INK4a immunohistochemistry as an effective biomarker to predict the outcomes of CIN.

Methods

p16^INK4a immunohistochemistry was performed in patients with CIN from January 2000 to August 2009. Among these patients, we have performed a retrospective analysis of the medical records to evaluate the outcome of CIN 1-2 and performed statistical analysis to determine the correlation between p16^INK4a expression and the outcomes. We also performed HPV genotyping and analyzed the relation between the infecting human papillomavirus (HPV) genotype and the outcomes.

Results

A total of 244 patients, including 82 with CIN 1, 60 with CIN 2, and 102 with CIN 3, were examined. The rate of p16^INK4a overexpression increased with increasing CIN grade, 20.7% for CIN 1, 80.0% for CIN 2, and 89.2% for CIN 3, with significant differences between CIN 1 and CIN 2-3 group. In the 131 CIN 1-2 patients, the progression rate was significantly higher for the patients showing p16^INK4a overexpression than for those not showing p16^INK4a overexpression (p=0.005); the regression rate was also found to be significantly lower for the patients showing p16^INK4a overexpression (p=0.003). High-risk HPV genotypes were detected in 73 patients (73.7%). Both progression and regression rates were not significantly different between the high-risk HPV-positive and HPV-negative groups (p=0.401 and p=0.381, respectively).

Conclusion

p16^INK4a overexpression was correlated with the outcome of CIN 1-2, and p16^INK4a is considered to be a superior biomarker for predicting the outcome of CIN 1-2 compared with HPV genotyping.     

Risk of cervical intraepithelial neoplasia grade 2 or worse after conization in relation to HPV vaccination status

Human papillomavirus (HPV) is essential for developing cervical cancer and precancerous lesions. Currently, three vaccines are available, which are effective as prophylaxis against HPV infection, however, limited knowledge exists about the possible effect of vaccinating women treated with conization to prevent recurrence. The aim of our study was to examine the risk of cervical intraepithelial neoplasia grade 2 or worse (CIN2+) after conization according to HPV vaccination status. Using Danish nationwide registries, we identified women diagnosed with CIN3 on the cone (2006–2012) and their HPV vaccination status. Vaccinees were defined as women vaccinated between 3 months before until 1 year after conization. The women were followed from 1 year after conization until diagnosis of CIN2+, conization, death, emigration or end of follow-up. Cox proportional hazard regression was used to estimate hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) of CIN2+ comparing vaccinees with nonvaccinees. The HR was adjusted for age, histology on cone, education, year of conization, repeat conizations and CIN2+ lesions between conization and start of follow-up. Altogether 17,128 women were included (2,074 vaccinees). There was a statistically nonsignificant lower risk of CIN2+ among vaccinees (HR_adjusted = 0.86, 95% CI: 0.67–1.09). Women vaccinated 0–3 months before tended to have a slightly lower HR of CIN2+ (HR_adjusted = 0.77, 95% CI: 0.45–1.32) than women vaccinated 0–12 months after conization (HR_adjusted = 0.88, 95% CI: 0.67–1.14), although not statistically significantly different. Our results add to the current knowledge about the potential clinical effect of vaccination as an adjunct to conization of high-grade cervical neoplasia to decrease risk of recurrence.     

Clinical validation of methylation biomarkers for optimal detection of high-grade vulvar intraepithelial neoplasia

The precursor lesions of vulvar squamous cell carcinoma (VSCC) include human papillomavirus (HPV)-associated and HPV-independent squamous neoplasia with a varying cancer risk. Our study aimed to validate the accuracy of previously identified DNA methylation markers for detection of such high-grade vulvar intraepithelial neoplasia (VIN). A large clinical series of 751 vulvar lesions, originally diagnosed as high-grade VIN, were reassessed and categorized into HPV-associated or HPV-independent vulvar disease categories. Together with 113 healthy vulvar controls, all samples were tested for 12 methylation markers with quantitative multiplex methylation-specific PCR (qMSP). Performance of individual markers and selection of an optimal marker panel for detection of high-grade VIN was determined by logistic regression analysis. SST was the best-performing individual marker (AUC 0.90), detecting 80% of high-grade VIN cases, with excellent detection of HPV-independent VIN (95%), known to have the highest cancer risk. Merely 2% of controls tested methylation positive for SST. Selection of a marker panel, including ZNF582, SST and miR124-2, resulted in a comparably high accuracy for detection of high-grade VIN (AUC 0.89). In conclusion, we clinically validated the accuracy of 12 DNA methylation markers for detection of high-grade VIN. SST, as a sole marker or in a panel, provides an optimal diagnostic tool to distinguish high-grade VIN in need of treatment, particularly HPV-independent VIN, from low-grade or reactive vulvar lesions. These findings warrant further prognostic validation of methylation biomarkers for cancer risk stratification of patients with VIN.     

特异性siRNA抑制宫颈癌细胞CaSKi中HPV16 E6基因的表达

目的:研究RNAi技术抑制宫颈癌细胞CaSKi中HPV16 E6癌基因的表达以及对细胞生物学特性的影响。方法:构建真核细胞表达特异性shRNA的pGENESIL-1/E6(PS6)重组质粒,脂质体转染细胞后用半定量RT-PCR技术检测CaSKi细胞中E6mRNA水平的变化,然后用western blotting检测RNA干扰前后p53和p21蛋白的表达来验证RNAi效应。用透射电子显微镜观察CaSKi/PS6细胞形态变化;应用流式细胞仪检测细胞的凋亡和细胞周期的变化,最后利用细胞计数和裸鼠成瘤实验测定CaSKi/PS6细胞增殖能力。结果:成功构建了真核细胞表达特异性siRNA的PS6重组质粒;在RNA干扰24、48和72小时后CaSKi/PS6细胞中E6mRNA分别下降了21.50%、52.60%和65.60%;CaSKi/PS6细胞出现凋亡的特征性改变;RNA干扰24h、48h和72h后CaSKi/PS6细胞的凋亡率分别为27.94%、31.95%和56.63%,细胞生长周期停滞于S期。结论:应用RNA干扰技术能有效地、特异地抑制宫颈癌细胞中HPV16 E6基因的表达,为RNA干扰应用于研究宫颈癌发病分子机制、临床治疗和干预性预防提供了新的方法。