Human papillomavirus (HPV) 16 E6 variants in tonsillar cancer in comparison to those in cervical cancer in Stockholm, Sweden

Background

Human papillomavirus (HPV), especially HPV16, is associated with the development of both cervical and tonsillar cancer and intratype variants in the amino acid sequence of the HPV16 E6 oncoprotein have been demonstrated to be associated with viral persistence and cancer lesions. For this reason the presence of HPV16 E6 variants in tonsillar squamous cell carcinoma (TSCC) in cervical cancer (CC), as well as in cervical samples (CS), were explored.

Methods

HPV16 E6 was sequenced in 108 TSCC and 52 CC samples from patients diagnosed 2000–2008 in the County of Stockholm, and in 51 CS from young women attending a youth health center in Stockholm.

Results

The rare E6 variant R10G was relatively frequent (19%) in TSCC, absent in CC and infrequent (4%) in CS, while the well-known L83V variant was common in TSCC (40%), CC (31%), and CS (29%). The difference for R10G was significant between TSCC and CC (p = 0.0003), as well as between TSCC and CS (p = 0.009). The HPV16 European phylogenetic lineage and its derivatives dominated in all samples (>90%).

Conclusion

The relatively high frequency of the R10G variant in TSCC, as compared to what has been found in CC both in the present study as well as in several other studies in different countries, may indicate a difference between TSCC and CC with regard to tumor induction and development. Alternatively, there could be differences with regard to the oral and cervical prevalence of this variant that need to be explored further.     

Human papillomavirus and cervical cancer

Human papillomavirus (HPV) is a small non-enveloped icosahedral virus with a circular double-stranded DNA genome of 8 kilo base pairs. HPV particles reach and infect the basal cells of the stratified epithelia through small epithelial lesions. In the basal cells the viral DNA is maintained as episomes, which start to replicate when the host cells initiate terminal differentiation. In these differentiating cells the degradation of p53 by the E6 protein and the abrogation of the pRb functions by the E7 protein lead to the reactivation of the DNA synthesis machinery. After virus propagation the host cells usually die. On the other hand, in some of the infected cells, the E6 and E7 genes are integrated on rare occasion into cell DNA. The cell continuously expressing the E6 and E7 proteins from the integrated genes is immortalized and sometimes acquires malignant phenotype induced by the accumulated damages to DNA. Of more than 100 HPV genotypes recorded to date, 13 including types 16 and 18 are associated with cervical cancer. Expression of HPV major capsid protein L1 in some cultured cells results in production of virus-like particles (VLPs). The VLPs of types 6, 11, 16, and 18 were used as a prophylactic vaccine in recent clinical trials and shown to successfully induce type-specific neutralizing antibodies in the recipients.     

HPV testing for cervical cancer screening in Croatia

Opportunistic screening based on the Pap smear has been undertaken in Croatia since 1953. However, cervical cancer remains an important health problem in Croatia when compared to European countries with organised screening programmes. In Croatia, in addition to screening based on well established cytology, Human papillomavirus (HPV) testing is widely used as secondary test as a triage to borderline cytology and as a follow-up after treatment of severe cervical lesions. Many different approaches for HPV testing arose in Croatia over the last decade depending on the needs of each medical institution involved. Presently, there is an urgent need for better networking between the laboratories, the implementation of quality assessment and the adaptation of a uniform system of referring to and reporting of HPV testing. In conclusion, the best possible organisation for HPV testing would be essential for implementation of HPV testing as primary screening test in Croatia, an thus ultimately and hopefully, the more successful cervical cancer control.     

Association between human papillomavirus (HPV) DNA and micronuclei in normal cervical cytology

The aim of the present study was to investigate the association between HPV-DNA and micronucleus (MN) frequency in women with normal cervical cytology. A total of 158 normal cervical smears were analyzed cytologically. The HPV genome was amplified using the GP5+/bioGP6+ consensus primers. HPV-DNA of high-risk types 16, 18, 31, 33, 39, 45 and 59 were also investigated. Of the 158 samples, 20 (12.7%) and 47 (29.7%) were positive for HPV-DNA and MN, respectively. Evidence for MN was found in 11 out of 20 (55%) HPV-DNA positive samples and in 36 out of 138 (26.1%) HPV-DNA negative ones. MN presence was significantly higher in HPV-DNA positive samples (p = 0.016). On the other hand, the absence of MN observed in a considerable number of HPV-DNA negative samples (102) may be of great value in predicting the absence of HPV. The mean age of HPV-DNA positive women (34.2 ± 12.6) was significantly lower than the mean age of HPV-DNA negative women (43.9 ± 13.7) (p = 0.003). Infection by one or multiple HPV types was found in 11 out of 20 (55.0%) and 9 out of 20 (45.0%) samples, respectively. The evaluation of MN using cervical smears collected for cytology tests could, thus, be used as additional information to monitor a population’s exposure to HPV.     

Human papillomavirus (HPV) type distribution in Korean women: a meta-analysis

The aim of the present study is to estimate the overall prevalence and type distribution of human papillomavirus (HPV) in Korean women, through literature review and meta-analysis. We searched published data for the period between 1995 and 2007 using the following inclusion criteria; (1) studies using type-specific HPV tests, (2) data from Korean female, (3) with cytologic or pathologic results, (4) having more than 20 cases for each subgroup classified by cytologic results, and (5) HPV detection including types 16, 18, and at least one other type. In total, 18 studies (13,842 cases) published up to April 2007 were identified and selected. Adjusted overall HPV prevalence was 23.9% (95% CI: 23.8-24.1%) in women with normal cytology and 95.8% (95% CI: 95.4-96.2%) in women with cervical cancer. Type 16 was predominant regardless of cervical disease status, and type 58 occupied a significantly larger proportion in high-grade cervical intraepithelial lesions and cervical cancer in Korean women. HPV types 58, 33, and 52 together accounted for about 20% of infections in cervical cancer and high-grade intraepithelial lesions. After introduction of HPV prophylactic vaccines, extended protection, especially against types 58, 33, and 52, will be an important issue for cervical cancer prevention in Korea. The future dominant genotypes will require follow-up epidemiological studies with a large-scale, multicentered, and prospective design.     

HPV检测早期筛查宫颈癌的临床意义——附妇科门诊2761例宫颈拭子HPV分析

目的探讨女性HPV DNA检测在宫颈癌防治方面的意义。方法应用DNA杂交技术对2 761例妇科门诊就诊者基因分型检测。结果 2 761例样本中,HPV感染有768例,阳性率27.82%,HPV感染人次972人次。检测高危型HPV（16,18,31,33,35,39,45,51,52,56,58,59,68）813人次,占感染总人次的83.64%;检出低危型HPV（6,11,42,43,44）73人次,占感染总人次7.51%;中国人群常见型HPV（53,66,CP8304）86人次,占感染总人次的8.85%。165例样本中包含了25种亚型的感染。结论 DNA杂交技术检测HPV基因分型,可一次检测多种亚型,有利于对HPV多重感染的诊断和宫颈癌的防治,可作为宫颈癌筛查的手段。     

Cell block as an adjunct to conventional Papanicolaou smear for diagnosis of cervical cancer in resource-limited settings

OBJECTIVE: To assess the utility of indigenously prepared cell blocks (CBs) as an adjunct to a conventional smear test in providing a reliable diagnosis of clinically suspicious cervical cancer in resource-limited settings. METHODS: Eighty-six clinically suspicious cervical cancer cases underwent a conventional smear test, CB preparation from residual cellular samples and biopsies at the same sitting. Correlations were performed between these modalities in order to derive the sensitivity and specificity of the CB technique to diagnose cervical cancer. OBSERVATION & RESULTS: Out of 86 clinically suspicious cervical cancers, 72 (83.7%), 70 (81.4%) and 67 (77.9%) cases were diagnosed as malignant on tissue biopsies, CBs and smears respectively. CB-biopsy agreement in the diagnosis of malignancy was feasible in 87.5% of the cases while CB-Pap smear agreement was feasible in 92.5% of the cases. Sensitivity and specificity of CB preparation to diagnose malignancy was 92.5% and 100%, respectively, when the smear was taken as the reference test (excluding the unsatisfactory smears). When biopsy was taken as the gold standard, the sensitivity and specificity of CBs were 87.5% and 100% respectively (excluding the unsatisfactory biopsies). In 8/19 cases where the smear diagnoses were either unsatisfactory or atypical squamous cells/atypical glandular cells, CBs picked up malignant lesions. CONCLUSION: CBs prepared from the residual cellular sample of conventional cervical scrapes augment the sensitivity of the smear test. When used as an adjunct to the smear, CBs aid in providing a reliable diagnosis of cervical cancer in the majority of the clinically suspected cases and thus the biopsy load can be reduced significantly in resource-poor settings.     

Human papillomavirus and tar hypothesis for squamous cell cervical cancer

Cervical cancer is the second most common life-threatening cancer among women worldwide, with incidence rates ranging from 4.8 per 100,000 in the Middle East to 44.3 per 100,000 in East Africa. Human papillomavirus (HPV) infection, especially HPV-16 and HPV-18, plays a major role in the etiology of cervical cancer, but HPV alone is not sufficient to induce cancer. We propose that squamous cell cervical cancer is caused by an interaction of oncogenic viruses and cervical tar exposures. Cervical tar exposures occur from cigarette smoking, use of tar-based vaginal douche products (TBD), and long years of inhaling smoke from wood- and coal-burning stoves in poorly ventilated kitchens.     

Human papillomavirus DNA typing in the cervical specimens among women of Split and Dalmatian County

Human papillomavirus (HPV) infection is the main cause of cervical cancer, the second most common cancer in women worldwide. More than 200 types of HPV have been described, and within this range more than 40 types attack epithelium of genital tract. The types that were most commonly related to the development of cervical cancer are called high-risk types (HR HPV). There are very few studies about HPV prevalence in Croatia and there is an absolute lack of data for Split and Dalmatian County. Therefore, during a 6 month period, we routinely screened 570 women for HPV DNA at the Educational Public Health Institute of Split and Dalmatian County. HR HPV was detected in cervical exfoliated cells, by using Hybrid Capture 2 HPV DNA test. Out of the total number of tested women, 200 (35%) of them were positive to HR HPV Polymerase chain reaction (PCR) based assays were employed for HR HPV genotyping in positive specimens. The following frequency was observed: HPV 16 in 10%, HPV 18 in 6.1%, HPV 31 in 2.6%, HPV 33 in 1.9%, HPV 52 in 1.4%, HPV 59 in 0.7%, HPV 45 in 0.4% specimens, while 11.9% of tested specimens currently remained untyped. It is necessary to expand this study to a larger number of women, in order to better evaluate genital HPV types distribution among women in this region.     

Human papillomavirus (HPV) oncoprotein E6 facilitates Calcineurin-Nuclear factor for activated T cells 2 (NFAT2) signaling to promote cellular proliferation in cervical cell carcinoma

The calcineurin-NFAT signaling pathway regulates cell proliferation, differentiation, and development in diverse cell types and organ systems. Deregulation of calcineurin-NFAT signaling has been reported in leukaemias and few solid tumors such as breast and colon. In the present study, we found elevated calcineurin protein levels and phosphatase activity in cervical cancer cell lines and depletion of the same attenuated cell proliferation. Additionally, nuclear levels of NFAT2, a downstream target of calcineurin, viz, was found elevated in human papillomavirus (HPV) infected cells, HeLa and SiHa, compared to the HPV negative cells, HaCaT and C33A, indicative of its higher DNA binding activity. The nuclear levels of both NFAT1 and NFAT3 remain unaltered implicating they have little role in cervical carcinogenesis. Similar to the in vitro studies, the HPV infected human squamous cell carcinoma specimens showed higher NFAT2 levels compared to the normal cervical epithelium. Depletion of NFAT2 by RNAi attenuated growth of SiHa cells. Overexpression of HPV16 oncoproteins viz, E6 and E7 increased NFAT2 expression levels and DNA binding activity, while knockdown of E6 by RNAi decreased the same. Briefly, we now report an activation of calcineurin-NFAT2 axis in cervical cancer and a novel role of HPV oncoprotein in facilitating NFAT2 dependent cell proliferation.     

Preclinical model to test human papillomavirus virus (HPV) capsid vaccines in vivo using infectious HPV/cottontail rabbit papillomavirus chimeric papillomavirus particles

A human papillomavirus (HPV) vaccine consisting of virus-like particles (VLPs) was recently approved for human use. It is generally assumed that VLP vaccines protect by inducing type-specific neutralizing antibodies. Preclinical animal models cannot be used to test for protection against HPV infections due to species restriction. We developed a model using chimeric HPV capsid/cottontail rabbit papillomavirus (CRPV) genome particles to permit the direct testing of HPV VLP vaccines in rabbits. Animals vaccinated with CRPV, HPV type 16 (HPV-16), or HPV-11 VLPs were challenged with both homologous (CRPV capsid) and chimeric (HPV-16 capsid) particles. Strong type-specific protection was observed, demonstrating the potential application of this approach.     

Associations between prior HPV4 vaccine doses and cervical cancer screening participation

BackgroundCervical cancer screening, regardless of HPV vaccination, is a cornerstone of cancer prevention. This study evaluated associations between prior HPV vaccine doses and initiation and continued participation of screening by age at vaccination.MethodsUsing electronic medical records for a safety net healthcare system (Truman Medical Center), women aged 14⿿26 y vaccinated (n = 1123) between 07/01/2006 and 10/1/2009 were randomly selected and matched on birth year and health campus to unvaccinated (n = 1123) women. Frequency of screening was determined through 07/01/2013. Hazard ratios (HR) for screening were estimated using Cox proportional hazards regression.ResultsScreening rates were higher after vaccination: unvaccinated (53%), first (62%), second (59%) or third (61%) doses. Women who initiated screening were less likely to complete the vaccine series, regardless of age. Women receiving one dose were more likely than unvaccinated women to initiate screening (HR = 2.98 95% Confidence Interval (CI):2.45⿿3.61) and were more likely to screen than those receiving two (1 vs. 2, HR = 2.94 95% CI:2.09⿿4.14) or three doses (1 vs. 3, HR = 3.15 95% CI:2.21⿿4.48). Compared to unvaccinated women, women <21 y who completed 3-doses were 1.8-times more likely to screen at ⿥21 y, whereas vaccinated women ⿥21 y were more likely to screen regardless of number of doses (p < 0.0001).ConclusionsWomen who were vaccinated were more likely to screen than unvaccinated women; screening rate was highest after and occurred closest to the first vaccine dose. Research evaluating the efficacy of a one-dose vaccine is warranted and may provide both higher vaccination and screening rates.     

Cytological screening for cervical cancer and human papillomavirus in general practice.

In a retrospective study of cervical screening in a general practice in Birmingham 156 out of 1913 smears taken over three years showed some abnormality. Smears from 65 women showed severe non-specific inflammation, and 91 women had various grades of cervical intraepithelial neoplasia, of whom 53 were aged under 30 and 13 over 40. Of 35 women with clinical evidence of human papillomavirus, 21 had normal results on cervical testing and 14 abnormal results. The incidence of genital warts among sexually active young people is growing, but the association of human papillomavirus with abnormal cervical smears is not clear. The efficacy of screening in the United Kingdom must be improved by actively encouraging younger patients to attend for regular screening.     

High-risk human papillomavirus (HPV) in parotid lesions

Although several studies have reported that oropharyngeal infection with HPV may predispose to tumorigenesis, little is known about the etiological factors of salivary gland tumors and the presence of HPV. We studied 9 parotid lesions for HPV infection including an oncocytoma, an acinic cell carcinoma, a high-grade adenocarcinoma, a low-grade polymorphous adenocarcinoma, a Warthin's tumor and 2 pleomorphic adenomas, a lymphoepithelial cyst and a lipoma of the parotid gland. DNA was extracted from formalin-fixed and paraffin-embedded tissue sections. Solution PCR for HPV detection was performed using the GP5+/GP6+ primers, while HPV typing was carried out by multiplex PCR for HPV6, 11, 16, 18, and 33; positive samples were recorfirmed by PCR with specific primers for each type. Quantitative real-time PCR for the high-risk HPV genotypes 16, 18, 31, 33, 35, 52, 58 and 67 was also performed to quantitate the viral load. Finally, in situ PCR was employed with HPV16-specific primers by direct-detection method. Seven of the 9 parotid lesions were HPV positive while 6 of these 7 had been infected by HPV16 and/or HPV18 oncogenic types. High viral load of highrisk genotypes of HPV was found in the oncocytoma, in one of the pleomorphic adenomas, and in the Warthin's tumor. Finally, in situ PCR indicated that HPV16 amplification occurred in the salivary gland tumors. This is the first time that highrisk HPV genotypes are detected in these histological types of parotid lesions, suggesting the possible involvement of the virus in the disease.     

Beyond HPV: Oncomirs as new players in cervical cancer

MicroRNAs (miRNAs) are a recently discovered family of 18-24 nucleotide non-coding RNAs that can negatively regulate target mRNAs. All studied multicellular eukaryotes utilize miRNAs to regulate basic cellular functions including proliferation, differentiation, and death. It is now apparent that abnormal miRNA expression is a common feature of human malignancies. This review discusses the various cancer-relevant miRNAs (oncomirs) especially in cervical tumorigenesis and the potential role of oncomirs as therapeutic agents and targets for the treatment of cervical cancer.     

Human papillomavirus DNA and liquid-based cervical cytology cotesting in screening and follow-up patient groups

OBJECTIVE: To compare the use of human papillomavirus (HPV) DNA and cervical cytology cotesting in screening and follow-up of patients with previous cervical abnormalities and to assess the significance of a positive HPV DNA test result in re-screening of cytologically normal cases. STUDY DESIGN: Cellular samples collected in liquid-based fixative were used for both cervical cytology and HPV DNA testing. The cervical cytology slides were manually screened by cytotechnologists followed by rapid re-screening by pathologists. The HPV DNA tests were performed using hybrid capture test kits. Statistical analyses of cervical cytology results and HPV DNA tests for high- and low-risk HPV from both patient groups were carried out. RESULTS: The prevalence of HPV DNA-positive cases was higher in younger patients. There was a poor correlation between cervical cytology results and HPV DNA tests for the screening group (kappa = 0.23), but a fair to good correlation was obtained for the follow-up group (kappa = 0.51). The false negative fraction of cytology negative/HPV DNA positive cases (0.1317), as compared with cytology negative/HPV DNA negative cases (0.0056), was statistically significant (p = 0.000001). CONCLUSION: The prevalence of HPV DNA decreased with increasing age in both the screening and follow-up patient groups. Virus clearance was delayed in the follow-up group as compared with the screening group. There was a poor correlation between cervical cytology and HPV DNA tests in the screening group but a fair to good correlation in the follow-up patient group. Cotesting of HPV DNA and cervical cytology increases the sensitivity and decreases the false negative fraction, suggesting that cotesting could be used to increase the interval of screening.