Effectiveness of HPV 16 viral load and the E2/E6 ratio for the prediction of cervical cancer risk among Chinese women

The effectiveness of the E2/E6 ratio, the state of viral genome integration and the viral load of human papillomavirus 16 (HPV 16) in predicting the risk of cervical cancer among Chinese women was investigated. Quantitative PCRs for the E2/E6 ratio and the viral load were performed on 85 cervical cancer samples and 55 HPV 16 positive healthy controls. The integrated form of the viral genome was found in 10.9% control samples and in 26.4% cervical cancer samples (P = 0.02). The majority of the cervical cancer (63.2%) and control samples (60%) were mixed forms. The E2/E6 ratio was associated with a high risk of cervical cancer (OR = 7.29, P = 9.55E?6). The integrated form (OR = 6.54, P = 0.005) and mixed form (OR = 2.93, P = 0.042) increased the risk of cervical cancer. The mean viral load in cervical cancer samples (37,371 ± 227,135) was higher than that in the controls (4,619 ± 27,079; P = 0.011). Additionally, the viral load increased along with the cervical cancer progression from the International Federation of Gynecology and Obstetrics (FIGO) stage I (12,337 ± 25,604) to stage II (67,453 ± 319,821). Compared with the state of viral genome integration (area under the receiver operating characteristic curve (AUC) = 0.743) or the viral load (AUC = 0.694), the E2/E6 ratio improved the effectiveness of the risk prediction of cervical cancer (AUC = 0.777), with the sensitivity (specificity) 81.2% (71.7%). The state of viral genome integration and the viral load of HPV 16 were important factors for the risk prediction of cervical cancer among Chinese women, and the E2/E6 ratio had a better cervical cancer risk prediction with age adjustment. J. Med. Virol. 85:646–654, 2013. © 2013 Wiley Periodicals, Inc.     

Significance of HPV 16 and 18 viral load quantitation in women referred for colposcopy

The clinical utility of HPV 16 and 18 viral loads remains debated. The aim of this study was to assess the clinical significance of HPV 16 and 18 viral load and to determine a cut‐off for optimal prediction of grade 2 or higher cervical intraepithelial neoplasia among patients referred to colposcopy. A total of 186 cervico‐vaginal specimens harboring HPV 16 and/or 18 obtained at the time of colposcopy from patients without previous cervical neoplasia were tested for HPV 16 and 18 detection and quantitation using quantitative duplex real‐time PCR method. Grade 2 or higher cervical intraepithelial neoplasia was diagnosed in 87 (46.8%) cases. Only HPV 16 median viral load increased significantly with the lesion grade: 9.1 × 10⁴ in normal cervix or grade 1 cervical intraepithelial lesion versus 4.0 × 10⁶ copies per million cells in grade 2 or higher cervical intraepithelial lesion (P < 0.001). The highest predictive value for grade 2 or higher cervical intraepithelial lesion was observed with a HPV 16 viral load cut‐off of 3.0 × 10⁶ copies per million cells (91% specificity, 58.2% sensitivity). Using this cut‐off, the highest predictive value of HPV 16 viral load was observed among those referred for previous low‐grade abnormal cervical cytology (96.4% specificity, 88% sensitivity). HPV 18 quantitation showed very poor predictive value. Specific attention should be given when performing colposcopic examination of women with an HPV 16 viral load higher than 3.0 × 10⁶ copies per million cells, especially among those referred after a low‐grade abnormal cytology. J. Med. Virol. 84:306–313, 2012. © 2011 Wiley Periodicals, Inc.     

Viral load and genomic integration of HPV 16 in cervical samples from HIV-1-infected and uninfected women in Burkina Faso

The relationships between human papillomavirus type 16 (HPV 16) viral load, HPV 16 integration status, human immunodeficiency virus type 1 (HIV-1) status, and cervical cytology were studied among women enrolled in a cohort of female sex workers in Burkina Faso. The study focused on 24 HPV 16-infected women. The HPV 16 viral load in cervical samples was determined by real-time PCR. Integration ratio was estimated as the ratio between E2 and E6 genes DNA copy numbers. Integrated HPV16 viral load was defined as the product of HPV 16 viral load by the integration ratio. High HPV 16 viral load and high integration ratio were more frequent among women with squamous intraepithelial lesions compared with women with normal cytology (33% vs. 11%, and 33% vs. 0%, respectively), and among women with high-grade squamous intraepithelial lesions compared with women without high-grade squamous intraepithelial lesions (50% vs. 17%, and 50% vs. 11%, respectively). High HPV 16 DNA load, but not high integration ratio, was also more frequent among HIV-1-positive women (39% vs. 9%; and 23% vs. 18%, respectively). The absence of statistical significance of these differences might be explained by the small study sample size. High-integrated HPV 16 DNA load was significantly associated with the presence of high-grade squamous intraepithelial lesions (50% vs. 5%, P = 0.03) in univariate and multivariate analysis (adjusted odds-ratio: 19.05; 95% confidence interval (CI), 1.11-328.3, P = 0.03), but not with HIV-1 or other high-risk HPV types (HR-HPV). Integrated HPV 16 DNA load may be considered as a useful marker of high-grade cervical lesions in HPV 16-infected women.     

Dynamics of HPV16 DNA load reflect the natural history of cervical HPV-associated lesions.

BACKGROUND: High burden of high risk human papillomavirus (HR HPV) has been shown to be predictive for the development of high grade cervical lesions and invasive cancers. However, low viral load cannot inevitably exclude progression towards cervical diseases. Moreover, few studies addressed whether viral load could predict infection clearance. OBJECTIVES: We carried out a retrospective study to analyze the variations of HPV16 load over time as a predictive marker of clinical outcome. STUDY DESIGN: The population consisted of 38 women who were found HR HPV positive by HCII test at study entry. Among them, 13 had developed a CIN2/3 (cases) and 25 had a negative HCII test and a normal cytology (controls) at study exit. The HPV16 DNA loads were quantified in 132 longitudinal cervical samples using quantitative real-time PCR. RESULTS: At study entry, the median of HPV16 load was not statistically different between controls and cases. However, when using a cut-off value of 200 copies/10(3) cells, the rate of cumulative incidence of CIN2/3 at 18 months increased from 14% in women with a load200 copies/10(3) cells. The longitudinal analysis performed on follow-up samples showed that in cases the progression to CIN2/3 was linked to HPV16 burden increasing over time, whereas in controls a decrease of at least 1 log HPV16 DNA load was observed over>or=2 time points. CONCLUSIONS: These results show that kinetics of HPV load, rather than a single HPV detection, might be more reliable to estimate whether a HPV infection will progress or be cleared.     

A novel real-time genotyping assay for detection of the E6-350G HPV 16 variant

It has been suggested that some E6 human papillomavirus (HPV) type 16 variants could be involved in viral persistence and progression of HPV infection. A novel one-step allelic discrimination real-time PCR was evaluated for E6-350G variant detection in 102 endocervical HPV 16 positive samples. This assay was also used to assess the distribution of this variant in Spanish women with cervical cancer related to HPV 16.The detection limit for the allelic discrimination assay was 50 copies per reaction, even where the E6-350G variant represents only 20% of the variants in the sample. Complete concordance was observed between DNA sequencing and the novel AD RT-PCR assay. Fourteen E6-350T reference strains and 18 E6-350G variants were detected out of 32 endocervical samples from women with cervical cancer. The average age of women who were infected by the E6-350G HPV 16 variant was 10 years lower in these samples than in women who were infected by the reference strain.This novel allelic discrimination assay is a fast, sensitive and specific method for detection of the E6-350G HPV 16 variant.     

子宫颈组织中人乳头瘤病毒16型E6基因片段的定量PCR检测

目的探讨子宫颈组织中人乳头瘤病毒(HPV)16型E6基因的含量与疾病严重程度的关系.方法用定量聚合酶链反应(PCR)检测20例慢性宫颈炎,6例宫颈非典型增生,18例宫颈癌组织中HPV16E6基因的拷贝数.结果HPV16E6基因在慢性宫颈炎,宫颈非典型增生及宫颈癌组织中的平均拷贝数(拷贝/μgDNA)分别为6.16×104,5.33×106和6.45×106.统计学处理表明,宫颈非典型增生及宫颈癌组织中E6基因的拷贝数显著高于慢性宫颈炎(P<0.01),宫颈癌组织中E6基因的拷贝数高于宫颈非典型增生组织,但差异无显著性(P>0.05).结论HPV16E6基因的拷贝数与宫颈疾病程度呈正相关,定量检测HPV16E6基因可作为监测宫颈癌高危人群的一种方法.     

Testing for human papillomavirus and measurement of viral load of HPV 16 and 18 in self‐collected vaginal swabs of women who do not undergo cervical cytological screening in Southern France

Self‐sampling using vaginal swabs could be a valuable alternative to screen for cervical cancer for women who do not attend regular cytological screening. The aim of this study was to determine the prevalence of high and low‐risk HPV types and of HPV type 16 and 18 DNA load in self‐collected vaginal swabs from 35‐ to 69‐year‐old Southern French women of low socioeconomic level or migrant populations who do not attend regular cervical screening. A good concordance (93.1%) was found between cervical brush and vaginal swabs in 29 samples. Self‐collected vaginal swabs were examined from 120 women. HPV infection was found in 28 women (23.3%; median age 48 years), 17 (14.1%) of whom harbored high‐risk HPV types. HPV type 16 was the high risk type found most frequently, followed by types 53, 31, 18, 58, and 66. The low‐risk type detected most frequently was HPV type 6, followed by types 61, 70, and 81. The mean HPV 16 and 18 load was 6.3 log₁₀ copies/10⁶ cells and 2.4 log₁₀ copies/10⁶ cells, respectively. These results suggest that vaginal self‐swabs can be a reliable tool for cervical cancer screening in non‐attending and inadequately screened elderly women. J. Med. Virol. 82:1431–1437, 2010. © 2010 Wiley‐Liss, Inc.     

Early integration of high copy HPV16 detectable in women with normal and low grade cervical cytology and histology

BACKGROUND: Integration of human papillomavirus (HPV) DNA has been considered a late event in cervical carcinogenesis. However, integrated forms of HPV were recently detected in cancer precursor lesions using a new real time polymerase chain reaction (PCR) to detect the deletions at the 3362-3443 region of HPV16 E2 Objective: To study the frequency of HPV16 DNA integration in cervical lesions and compare the sensitivity of an additional upstream region of the E2 ORF (2962-3138) in detecting HPV integration. METHODS: Using the TaqMan based PCR, HPV16 positive DNA samples were analysed in 164 cervical scrapings from women participating in a multicentre screening trial. Biopsy confirmation was available in 62 cases. RESULTS: Primers targeting the 3362-3443 region detected the majority of E2 deletions. In only 23% of the samples was the E2 upstream region equal or better target than the 3362-3443 region. Mixed (episomal/integrated) pattern was the most prevalent physical state of HPV16, also present in PAP smears with normal morphology. Pure integrated form was most prevalent in HSIL and cancer lesions, but also detectable in low grade abnormalities (NSIL, ASC-US, LSIL). Women with only integrated HPV16 were almost 10 years older than those with episomal HPV16. Viral load of integrated HPV16 was related to cytological abnormality (p = 0.003) but not to histology. CONCLUSIONS: Integrated HPV16 is present in low grade cervical lesions, mostly mixed with the episomal form. Women with the pure integrated form of HPV16 are older than those with the other forms.     

广州东部妇女宫颈人乳头瘤病毒16型感染及基因分析

目的 研究广州东部妇女中人乳头瘤病毒16型(HPV-16)宫颈感染分布,分析其早基因E6/E7的多态性,分析L1和E6基因定量与病程的关系.方法 通过导流杂交基因芯片技术检测宫颈脱落细胞的HPV-16感染;通过特异性扩增获取病毒早基因E6/E7序列,克隆测序并进行多态性分析;荧光定量PCR技术对E6基因和L1基因进行定量分析.结果 806例宫颈脱落细胞样本中HPV-16感染阳性36例(4.5%),其中18例(50.0%)宫颈细胞发生高度以上病变;7例(4例低度或以下病变,3例高度以上病变或浸润癌)阳性标本得到E6/g7序列有15个位点分别出现变异;高度病变组(A组,11例)与低度或以下病变组(B组,14例)的L1基因和E6基因定量数据对数值均有显著差异(P<0.05),但L1/E6比值差异无统计学意义(P=0.19).结论 本地区在17～62岁妇女中HPV-16感染阳性发生率约4.5%,50.0%发生高度以上宫颈病变,本研究显示病毒基因拷贝数与宫颈病变程度可能有关,L1/E6比值未能提示病毒整合的发生.     

Viral load and physical status of human papillomavirus (HPV) 18 in cervical samples from female sex workers infected with HPV 18 in Burkina Faso

Viral DNA load and physical status might be predictive of either high‐grade cervical lesions or disease progression among women infected by human papillomavirus (HPV) 16, but these virological markers have rarely been studied in HPV 18 infections. The relationships between HPV 18 DNA load, viral genome physical status and cervical squamous intraepithelial lesions were analyzed among female sex workers infected with HPV18 in Burkina Faso. HPV 18 E2 and E6 genes were quantitated by real‐time PCR. Among 21 women infected with HPV 18, 67% of whom were HIV‐1‐seropositive, 11 (52.4%) had a normal cytology, 8 (38.1%) had low‐grade squamous intraepithelial lesions, and 2 (9.5%) had high‐grade squamous intraepithelial lesions. Total viral load and integrated viral load were higher in women with squamous intraepithelial lesions than in women with normal cytology (P = 0.01 for both parameters). Total viral load and integrated viral load were higher in HIV‐1‐seropositive women than in those who were not infected with HIV (P = 0.01, and P, 0.01, respectively). Total viral load or integrated viral load >1,000 copies/ng of DNA were more frequent in women with squamous intraepithelial lesions than in women with normal cytology (7/10 vs. 1/11; P = 0.007) and in HIV‐1‐seropositive women (8/14 vs. 0/7 in HIV‐uninfected women; P = 0.02). Both HPV 18 DNA and integrated DNA loads might represent markers of cervical lesions. Prospective evaluations are needed to establish the value of these parameters to predict high‐grade lesion or lesion progression. J. Med. Virol. 81:1786–1791, 2009. © 2009 Wiley‐Liss, Inc.     

Distribution and viral load of eight oncogenic types of human papillomavirus (HPV) and HPV 16 integration status in cervical intraepithelial neoplasia and carcinoma.

Current human papillomavirus (HPV) DNA testing using pooled probes, although sensitive, lacks specificity in predicting the risk of high-grade cervical intraepithelial neoplasia (CIN 2/3) progression. To evaluate selected HPV genotyping, viral load, and viral integration status as potential predictive markers for CIN progression, we performed HPV genotyping in formalin-fixed, paraffin-embedded cervical tissue with cervical carcinoma (29 cases) and CINs (CIN 1, 27 cases; CIN 2, 28 cases; CIN 3, 33 cases). General HPVs were screened using consensus primers GP5+/GP6+ and PGMY09/11. HPV genotyping and viral load measurement were performed using quantitative real-time PCR for eight oncogenic HPV types (16, 18, 31, 33, 35, 45, 52, and 58). HPV 16 viral integration status was evaluated by measuring HPV 16 E2/E6 ratio. We observed that HPV DNA positivity increased in parallel with the severity of CINs and carcinoma, with 59% positivity in CIN 1, 68% in CIN 2, 76% in CIN 3, and 97% in carcinoma (P trend=0.004). The eight oncogenic HPV types were significantly associated with CIN 2/3 (81%) and carcinoma (93%) (odds ratio (OR), 15.0; 95% confidence interval (CI), 5.67-39.76; P<0.0001) compared with the unknown HPV types (OR, 2.87; 95% CI, 0.89-9.22; P=0.08). HPV 16 was the predominant oncogenic HPV type in CIN 2/3 (51%) and carcinoma (71%) and integrated significantly more frequently in carcinoma than in CIN 2/3 (P=0.004). No significant differences in viral load were observed across the disease categories. Our findings suggest that selected genotyping for the eight oncogenic HPV types might be useful in separating women with a higher risk of CIN progression from those with a minimal risk. We also conclude that the HPV 16 integration status has potential to be a marker for risk assessment of CIN progression.     

Prevalence of the most common high-risk HPV genotypes among women in three new independent states of the former Soviet Union

Type distribution of HPV has been studied in different geographic regions, but the data are scanty from the new independent states of the former Soviet Union. Here the HPV prevalence and distribution of the most frequent high-risk HPV types among 3,187 women at different risk for HPV and cervical intraepithelial neoplasia in Russia, Belarus, and Latvia is reported. HPV detection, type distribution and viral load analysis in DNA samples from cervical scrapes were done with real-time PCR-based assay detecting HPV types 16, 18, 31, 33, 35, 39, 45, 52, and 58. The overall HPV prevalence was 31.2%, HPV16 was the most prevalent type followed by HPV31 and HPV33 group. The overall HPV prevalences in Russia, Belarus and Latvia were 33.4%, 27.5%, and 26.2%. The type distributions were similar in these countries, except for Latvia where HPV39 was the third prevalent genotype. HPV prevalence was highest (40.8%) among women from sexually transmitted disease clinic, followed by 30.9% among gynecological outpatients and 27.2% in screening patients. HPV detection increased with cytological abnormality (P = 0.0001) and lesion grade in the biopsy (P = 0.0001), from 27% to 72% in normal samples to cancer, and from 64% to 77% in cervical intraepithelial neoplasia 1 to cancer. The normalized viral loads varied greatly between and among different HPV-types. The mean log HPV33 group copies/cell increased from negative for intraepithelial lesions to cancer (P = 0.049). Distribution of the most common high-risk HPV-types seems to be similar in these countries as reported in other major geographical regions.     

Quantitative analysis of human papillomavirus type 16 in cervical neoplasm: a study in Chinese population.

BACKGROUND: Human papillomavirus (HPV) infection was recognized as a major causal factor for the development and progression of squamous intraepithelial lesions (SIL). It is possible to use HPV test for the detection of cervical lesions as an adjunct to cervical cytology. OBJECTIVES: To evaluate the relation between HPV 16 viral load and the severity of cervical lesions in a Chinese population. METHODS: Study population was recruited from the colposcopy and general outpatient clinic. The presence of HPV 16 E6 and E7 in cytological specimens was detected using HPV 16 specific polymerase chain reaction (PCR). The viral load in the specimens that were positive for HPV 16 specific PCR, was quantified by using real-time PCR assay. RESULTS: The study recruited 394 women, in which 148 were high-grade SIL (HG-L), 121 were low-grade SIL (LG-L) and 125 were Normal. Sufficient DNA integrity was proven in 347 samples. Among 121 positive cases for HPV 16, 70 were HG-L, 34 were LG-L and 17 were Normal. Using quantitative real-time PCR, the percentages of samples with greater DNA copies were found to increase with the severity of diseases. There was also a significant difference in DNA copies among the three groups (HG-L versus Normal, p<0.001; HG-L versus LG-L, p<0.001). Area under receiver operating characteristic (ROC) curve of the HG-L versus LG-L and Normal was 0.836 indicating that quantitative PCR had a good diagnostic value in differentiating HG-L from the LG-L and Normal groups. CONCLUSIONS: Our data suggested HPV 16 viral load was significantly related to the severity of cervical lesions. Evaluation of viral burden could be a potential clinical tool in management of cervical lesions.     

Reproducibility of HPV 16 and HPV 18 viral load quantitation using TaqMan real-time PCR assays

A reproducibility study was designed to assess within-assay, between-day, and interlaboratory variability of three real-time PCR assays targeting HPV 16, HPV 18, and the human glyceraldehyde-3-phosphate dehydrogenase (GAPDH) pseudogenes. Fifteen HPV 16 and fifteen HPV 18 cervical swab samples were amplified in triplicate by GAPDH and HPV 16 and by GAPDH and HPV 18 assays, respectively. All samples were amplified undiluted and at a 1:10 dilution on 2 separate days in the same laboratory, and the same samples were amplified in a separate laboratory. HPV 16 and HPV 18 normalized viral load is reported as the number of HPV genomes per 20000 GAPDH copies. The analytic specificity of the HPV 16 and 18 assays was 100 and 97%, respectively. The intraclass correlation coefficients (ICC) were 0.99, 0.97, and 0.98 for HPV 16, HPV 18, and GAPDH, respectively, indicating that the variability due to experimental error was very low. Ten-fold differences in viral load could be readily discriminated across a six order of magnitude dynamic range (ca. 5-5x10(6) copies). Power of discrimination was increased at higher target concentrations (>5000 copies). The correlation of normalized HPV 16 and 18 viral load was high between the two laboratories (Spearman rho (rho)=0.96 and 0.87, respectively). These HPV 16 and HPV 18 quantitative PCR assays with GAPDH normalization are reproducibly quantitative over a broad linear dynamic range allowing for application in epidemiologic studies for measurement of viral load.     

Variation in human papillomavirus type-16 viral load within different histological grades of cervical neoplasia

The objective of this study was to investigate variation in human papillomavirus (HPV) type-16 load within histologically defined grades of cervical intraepithelial neoplasia. Two hundred and thirty-seven liquid based cytology samples were collected from women attending colposcopy clinics, DNA was extracted, and presence of virus determined by PCR-enzyme immunoassay. Quantitative real-time PCR was used to determine viral load for 70 HPV-16 positive single infections. Viral load was expressed as the ratio of copies of the viral L1 gene to copies of the human beta-globin gene. Measurements varied from 0.019 to 4,194 HPV genomes per cell. Our data demonstrate that in cervical neoplasia, HPV load tends to correlate with disease severity, but that the number of viral genomes/cell varies considerably within histological grades. This variation within disease grades currently limits the clinical utility of viral load measurement.     

Human papillomavirus (HPV) DNA copy number is dependent on grade of cervical disease and HPV type

The association between human papillomavirus (HPV) DNA copy number and cervical disease was investigated. Viral DNA copy number for the most common high-risk HPV types in cervical cancer (types 16, 18, 31, and 45) was determined in cervical cytobrush specimens from 149 women with high-grade cervical intraepithelial neoplasias (CIN II-CIN III), 176 with low-grade CIN (CIN I), and 270 with normal cytology. Quantitative, PCR-based fluorescent assays for each of the HPV genotypes and for the beta-globin gene were used. The amount of cellular DNA increased significantly with increasing disease; thus, HPV was expressed as copies per microgram of cellular DNA. The assay had a dynamic range of >10(7), allowing documentation for the first time of the wide range of HPV copy numbers seen in clinical specimens. Median HPV DNA copy number varied by more than 10(4) among the viral types. HPV16 was present in the highest copy number; over 55% of HPV16-positive samples contained more than 10(8) copies/microgram. Median copy number for HPV16 showed dramatic increases with increasing epithelial abnormality, an effect not seen with the other HPV types. HPV16 increased from a median of 2.2 x 10(7) in patients with normal cytology, to 4.1 x 10(7) in CIN I patients, to 1.3 x 10(9) copies/microgram in CIN II-III patients. Even when stratified by cervical disease and viral type, the range of viral DNA copies per microgram of cellular DNA was quite large, precluding setting a clinically significant cutoff value for "high" copy numbers predictive of disease. This study suggests that the clinical usefulness of HPV quantitation requires reassessment and is assay dependent.     

Molecular variants of HPV type 16 E6 among Mexican women with LSIL and invasive cancer.

BACKGROUND: Cervical cancer is the second most common cancer in women worldwide. Infection with human papillomavirus (HPV) 16 is an important risk factor associated with cervical cancer, more than 50% of cervical cancer tissues have DNA of HPV 16. Intratypic variants have been reported, although they differ in prevalence, biological and biochemical properties, their implication in the aetiology of cervical cancer is still uncertain. OBJECTIVE: To identify HPV type 16 E6 variants among Mexican women with diagnosis of low-grade squamous intraepithelial lesion (LSIL) or invasive cancer (IC). STUDY DESIGN: Forty HPV16-positive samples were included, 15 were from women with LSIL, 25 from women with IC; 610 pb from the E6 gene were amplified by PCR and the variant status subsequently determined by hybridization with 27 biotinilated probes. Statistical analysis was performed with chi2, odds ratio (OR). RESULTS: In the LSIL group we only found ten (66%) EP and five (33%) EP350G variants. In the IC group, four variants were found; 11 (44%) AA, seven (28%) EP, six (24%) EP350G, one (4%) Af2. Comparison of the frequency of variants differed from EP in both groups of patients (P=0.01) with an odds ratio (OR) of 5.14 (CI 95% [1.07-26.56]). CONCLUSION: This study demonstrates an association between HPV type 16 variants different from prototype (EP) and invasive cervical cancer.