Human papillomavirus: science and technologies for the elimination of cervical cancer

Human papillomavirus and ovarian cancer (review of literature and meta-analysis)

Many factors are involved in carcinogenesis of the ovary, such human genetic and physiological characteristics as lifestyle, existing diseases of the reproductive system, and, as suggested, the human papillomavirus (HPV). It is well known that the human papillomavirus virus of high carcinogenic risk (HCR) plays a crucial role in the onset and development of cervical cancer, as well as cases of HPV positive breast cancer and endometrial cancer. The data on the presence of HPV in ovarian cancer are ambiguous: the researchers claim that there is no complete effect of the virus on the development of this type of cancer, and the detection of HPV in 60-80% of tumors. In this regard, there is a need to systematize the currently available research results on this controversial issue and conduct a meta-analysis of the association of HPV infection with the risk of ovarian cancer.

Evaluation of the SureX HPV genotyping test for the detection of high-risk HPV in cervical cancer screening

BACKGROUND

The SureX HPV genotyping test (SureX HPV test), which targets the human papillomavirus (HPV) E6/E7 genes was compared with the Cobas 4800 and Venus HPV tests for detecting 14 high-risk HPV (HR-HPV) types in clinical referral and follow-up patients to evaluate its value for cervical cancer screening.

METHODS

Two different populations were enrolled in the study. The first population comprised 185 cases and was used for comparing the SureX HPV test (Health, China) with the Cobas 4800 test (Roche, USA). The second population comprised 290 cases and was used for comparing the SureX HPV test (Health, China) with the Venus HPV test (Zhijiang, China). Polymerase chain reaction (PCR) sequencing was performed for further confirmation of discordant results.

RESULTS

In the first population, the overall agreement rate was 95.6% for 14 high-risk HPV types. Eight discordant cases were confirmed by PCR sequencing, which showed that the agreement rates were 75.0% between the SureX HPV test and PCR sequencing and 25.0% between the Cobas 4800 test and PCR sequencing (P < 0.01). In the second population, the overall agreement rate was 95.5%. Thirteen discordant cases were confirmed by PCR sequencing, which showed that the agreement rates were 76.9% between the SureX HPV test and PCR sequencing and 23.1% between the Venus HPV test and PCR sequencing (P < 0.01). With cervical intraepithelial neoplasia grade 2+ (CIN2+) as the reference standard, the sensitivity values of the SureX HPV test and the Venus HPV test were 93.5% and 92.0%, (P > 0.05), while the specificity values were 43.3% and 46.7%, respectively (P > 0.05).

CONCLUSION

The SureX HPV test had good consistency with both the Cobas 4800 and Venus HPV tests for 14 HR-HPV types. In addition, it avoided some false negatives and false positives. Therefore, the SureX HPV test can be used for cervical cancer screening.

Clinical performance of Onclarity HPV assay and Cobas HPV test in detection of cervical precancer and cancer in Chinese women

OBJECTIVE

The Roche Cobas (Cobas) and BD Onclarity (Onclarity) human papillomavirus (HPV) assays are convenient, PCR-based, HPV DNA tests; currently, data on performance of Onclarity in Chinese women is limited. We aimed to evaluate the clinical performance of Onclarity for detecting cervical lesions in Chinese women.

METHODS

In total, 1122 women were enrolled into this study. Exfoliated cervical cells were collected in PreservCyt medium and were tested using Cobas and Onclarity. Cytology and histology were interpreted by senior cytologists and a panel of pathologists, respectively, at Cancer Hospital, Chinese Academy of Medical Sciences.

RESULTS

The assays showed excellent concordance for HPV16 (kappa = 0.91, 95% CI: 0.85-0.97) and for 12 other high-risk types (HPV31/33/35/39/45/51/52/56/58/59/66/68, kappa = 0.84, 95% CI: 0.78-0.90), and very good concordance for HPV18 (kappa = 0.75, 95% CI: 0.69-0.81). No difference for ≥CIN2 sensitivity was observed between Onclarity and Cobas (both 90.5%); and the <CIN2 specificity for detection was similar between Onclarity (84.2%, 95% CI: 81.6-86.4) and Cobas (80.4%, 95% CI: 77.6-82.8). When combined with cytology triage, the colposcopy referral rate point estimate was slightly lower for Onclarity (9.0%) than for Cobas (11.0%), with the same ≥CIN2 sensitivity of 75.0% (95% CI: 53.1-88.8) for Onclarity and Cobas.

CONCLUSIONS

Onclarity exhibited comparable screening performance and triage efficiency compared to Cobas in detection of cervical lesions in Chinese women.

Human papillomavirus (HPV) vaccination: from clinical studies to immunization programs

Cervical cancer incidence and mortality have decreased in high-income countries, but low- and middle-income countries continue to bear a significant burden from the disease. Human papillomavirus (HPV) vaccines are a promising alternative for disease control; however, their introduction is slow in settings with greater need. We conducted a review of HPV vaccine efficacy and effectiveness reported in clinical trials and population-based studies. Efficacy of HPV vaccines is close to 100% when using a three-dose schedule in HPV-negative young women (<25 years old) for protection against persistent infection and HPV vaccine-type associated pre-cancerous lesions. Furthermore, sustained protection for up to 12 years of follow-up has been demonstrated; cross-protection against non-vaccine types is particularly observed for the bivalent vaccine, and preliminary data regarding impact on invasive cancer have emerged. Given its lower efficacy, catch-up vaccination beyond 19 years of age and proposals for vaccinating adult women deserve careful evaluation in accurately designed studies and economic analyses. Despite positive results regarding immunogenicity and post-hoc analysis for cervical intra-epithelial neoplasia in clinical trials, population-based data for prime and booster two-dose schedules are not available. Evaluation of vaccine safety from surveillance systems in immunization programs that have already distributed more than 270 million doses found no association of HPV vaccination with serious side effects. The introduction of HPV vaccination in national immunization programs remains the main challenge in tackling the burden of cervical cancer (up to 2018, only 89 countries have introduced vaccination worldwide, and most of these are high-income countries). Access models and technical capacity require further development to help low- and middle-income countries to increase the pace of vaccine delivery. Alternative approaches such as one-dose schedules and vaccination at younger ages may help reduce the programmatic and economic challenges to adolescent vaccination.

Association between Sedative-hypnotics and Subsequent Cancer in Patients with and without Insomnia: A 14-year Follow-up Study in Taiwan

Background: The aim of this population-based 14-year historical and prospective study was to determine the relationships between the usage of sedative-hypnotics, including benzodiazepines and nonbenzodiazepines, and the risk of subsequent cancer in patients with or without insomnia among the Taiwanese population.

Methods: A total of 43,585 patients were recruited, 21,330 of whom had been diagnosed with insomnia and 8,717 who had been prescribed sedative-hypnotics during this study's following period of 2002 to 2015. Information from the claims data, namely basic demographic details, drug prescriptions, comorbidities, and patients' survival, was extracted from the National Health Insurance Research Database for χ² analysis. A Cox proportional hazards model was used to compute the 14-year cancer-free survival rates after adjustment for confounding factors.

Results: Patients with insomnia who used sedative-hypnotics had an adjusted hazard ratio of 1.49 compared with patients with insomnia who did not use any sedative-hypnotics, and patients without insomnia who used sedative-hypnotics had an adjusted hazard ratio of 1.68 compared with patients without insomnia who did not use any sedative-hypnotics. Regarding site-specific risk, patients with insomnia who used sedative-hypnotics had an increased risk of oral and breast cancers, and patients without insomnia who received sedative-hypnotics prescriptions had an increased risk of liver and breast cancers. The cancer-free survival rate of patients who had used sedative-hypnotics was significantly lower than that of patients who had never used sedative-hypnotics.

Conclusions: The use of sedative-hypnotics in patients either with or without insomnia was associated with subsequent cancer development in the Taiwanese population. Increased risks of oral, liver, and breast cancer were found in the patients with the use of sedative-hypnotics. The use of sedative-hypnotics should be discouraged for treating patients with or without insomnia in Taiwan.

Integrative and episomal forms of genotype 16 of human papillomavirus in patients with cervical intraepithelial neoplasia and cervical cancer

The study involved 500 patients with LSIL (low grade squamous intraepithelial lesion), HSIL (high grade squamous intraepithelial lesion), stage I-IV cervical cancer, infected with human papillomavirus (HPV), as well as 235 women without pathological changes in cervical mucosa. The comprehensive survey included colposcopy, cytological and histological analysis, detection and genotyping of high-risk human papillomavirus. Viral load and physical status of HPV16 DNA was evaluated in cases of mono-infection (n = 148). The prevalence of virus-positive cases among the patients with LSIL/NSIL, cervical cancer patients and healthy women was 69.2%, 76.7% and 51.9%, respectively. An association between the severity of disease and high viral load was revealed. The frequency of integrated DNA was strongly increased in patients with a high viral load. The frequency of episomal forms was either reduced or not detecteable in patients with high viral load as compared to patients with low viral load. It is reasonable to suggest that a high HPV16 viral load may cause an increase in the frequency of integration of virus DNA into the cellular/host genome. This suggests that a high HPV16 viral load may be considered as a risk factor for prognosis of cervical intraepithelial neoplasia and cervical cancer.

Economic Evaluation of Screening Strategies Combined with HPV Vaccination of Preadolescent Girls for the Prevention of Cervical Cancer in Vientiane, Lao PDR

Background

Several approaches to reduce the incidence of invasive cervical cancers exist. The approach adopted should take into account contextual factors that influence the cost-effectiveness of the available options.

Objective

To determine the cost-effectiveness of screening strategies combined with a vaccination program for 10-year old girls for cervical cancer prevention in Vientiane, Lao PDR.

Methods

A population-based dynamic compartment model was constructed. The interventions consisted of a 10-year old girl vaccination program only, or this program combined with screening strategies, i.e., visual inspection with acetic acid (VIA), cytology-based screening, rapid human papillomavirus (HPV) DNA testing, or combined VIA and cytology testing. Simulations were run over 100 years. In base-case scenario analyses, we assumed a 70% vaccination coverage with lifelong protection and a 50% screening coverage. The outcome of interest was the incremental cost per Disability-Adjusted Life Year (DALY) averted.

Results

In base-case scenarios, compared to the next best strategy, the model predicted that VIA screening of women aged 30–65 years old every three years, combined with vaccination, was the most attractive option, costing 2 544 international dollars (I$) per DALY averted. Meanwhile, rapid HPV DNA testing was predicted to be more attractive than cytology-based screening or its combination with VIA. Among cytology-based screening options, combined VIA with conventional cytology testing was predicted to be the most attractive option. Multi-way sensitivity analyses did not change the results. Compared to rapid HPV DNA testing, VIA had a probability of cost-effectiveness of 73%. Compared to the vaccination only option, the probability that a program consisting of screening women every five years would be cost-effective was around 60% and 80% if the willingness-to-pay threshold is fixed at one and three GDP per capita, respectively.

Conclusions

A VIA screening program in addition to a girl vaccination program was predicted to be the most attractive option in the health care context of Lao PDR. When compared with other screening methods, VIA was the primary recommended method for combination with vaccination in Lao PDR.

Cervical Cancer Genetic Susceptibility: A Systematic Review and Meta-Analyses of Recent Evidence

INTRODUCTION

Cervical cancer (CC) has one of the highest mortality rates among women worldwide. Several efforts have been made to identify the genetic susceptibility factors underlying CC development. However, only a few polymorphisms have shown consistency among studies.

MATERIALS AND METHODS

We conducted a systematic review of all recent case-control studies focused on the evaluation of single nucleotide polymorphisms (SNPs) and CC risk, stringently following the "PRISMA" statement recommendations. The MEDLINE data base was used for the search. A total of 100 case-control studies were included in the meta-analysis. Polymorphisms that had more than two reports were meta-analyzed by fixed or random models according to the heterogeneity presented among studies.

RESULTS

We found significant negative association between the dominant inheritance model of p21 rs1801270 polymorphism (C/A+A/A) and CC (pooled OR = 0.76; 95%CI: 0.63-0.91; p<0.01). We also found a negative association with the rs2048718 BRIP1 polymorphism dominant inheritance model (T/C+C/C) and CC (pooled OR = 0.83; 95%CI: 0.70-0.98; p = 0.03), as well as with the rs11079454 BRIP1 polymorphism recessive inheritance model and CC (pooled OR = 0.79; 95%CI: 0.63-0.99; p = 0.04). Interestingly, we observed a strong tendency of the meta-analyzed studies to be of Asiatic origin (67%). We also found a significant low representation of African populations (4%).

CONCLUSIONS

Our results provide evidence of the negative association of p21 rs1801270 polymorphism, as well as BRIP1 rs2048718 and rs11079454 polymorphisms, with CC risk. This study suggests the urgent need for more replication studies focused on GWAS identified CC susceptibility variants, in order to reveal the most informative genetic susceptibility markers for CC across different populations.

Are the Two Human Papillomavirus Vaccines Really Similar? A Systematic Review of Available Evidence: Efficacy of the Two Vaccines against HPV

BACKGROUND

When the bivalent and the quadrivalent HPV vaccines were marketed they were presented as having comparable efficacy against cervical cancer. Differences between the vaccines are HPV types included and formulation of the adjuvant.

METHOD

A systematic review was conducted to assess the efficacy of the two vaccines against cervical cancer. Outcomes considered were CIN2+, CIN3+, and AIS.

RESULTS

Nine reports (38,419 women) were included. At enrollment mean age of women was 20 years, 90% had negative cytology, and 80% were seronegative and/or DNA negative for HPV 16 or 18 (naïve women). In the TVC-naïve, VE against CIN2+ was 58% (95% CI: 35, 72); heterogeneity was detected, VE being 65% (95% CI: 54, 74) for the bivalent and 43% (95% CI: 23, 57) for the quadrivalent. VE against CIN3+ was 78% (95% CI: <0, 97); heterogeneity was substantial, VE being 93% (95% CI: 77, 98) for the bivalent and 43% (95% CI: 12, 63) for the quadrivalent. VE in the TVC was much lower. No sufficient data were available on AIS.

CONCLUSIONS

In naïve girls bivalent vaccine shows higher efficacy, even if the number of events detected is low. In women already infected the benefit of the vaccination seems negligible.

Cervical cancer screening: A never-ending developing program

With the term “oncological screening”, we define the overall performances made to detect early onset of tumors. These tests are conducted on a population that does not have any signs or symptoms related to a neoplasm. The whole population above a certain age, only one sex, only subjects with a high risk of developing cancer due to genetic, professional, discretionary reasons may be involved. Screening campaigns should be associated, when risk factors that can be avoided are known, with campaigns for the prevention of cancer by means of suitable behavior. The goal of cancer screening cannot however be limited to the diagnosis of a greater number of neoplasms. Screening will be useful only if it leads to a reduction in overall mortality or at least in mortality related to the tumor. Screening should then allow the diagnosis of the disease at a stage when there is a possibility of healing, possibility that is instead difficult when the disease is diagnosed at the appearance of signs or symptoms. This is the reason why not all campaigns of cancer screening have the same effectiveness. In Italy, every year there are about 150000 deaths due to cancer. Some of these tumors can be cured with a very high percentage of success if diagnosed in time. Cervical cancer can be diagnosed with non-invasive tests. The screening test used all over the world is Papanicolaou (Pap) test. This test may be carried out over the entire healthy population potentially exposed to the risk of contracting cancer. Public health has begun the screening campaigns in the hope of saving many of the approximately 270000 new cases of cancer reported each year. Screening is done following protocols that guarantee quality at the national level: these protocols are subject to change over time to reflect new realities or to correct any errors in the system. A simplified sketch of a possible route of cancer screening is as follows: (1) after selecting the target population, for example all women between 25 and 64 years (in the case of monitoring of cervical cancer), an invitation letter with the date and time of the appointment, planned according to the acceptance capacity of the hospital, is sent to all individuals; (2) an examination, which depending on the individual and the type of cancer to be monitored, for example, can be a Pap smear, is performed and the patient can go home; (3) once available the results of examinations, if negative, they shall be communicated to the person concerned that will be notified by mail and will be recalled for a second test at a few years of distance, in the case of non-negativity, instead, the patient is contacted by telephone and informed of the need to carry out further examinations: it is said that the patient is in the “phase two” of the screening pathway; (4) in phase two, reached by only a small portion of the interested parties (usually less than 3%-5%), more in-depth tests are carried out, which, depending on the individual and the type of cancer, can be: cytological and colposcopic examinations, the removal of a fragment of tissue (biopsy) and subsequent histological examination, additional tests such as ultrasound, radiography, or others such as computerized tomography, magnetic resonance imaging, positron emission tomography, etc., in case of negativity, the concerned person will be called for new control tests at a a few years of distance, in case of non-negativity, it will be proposed instead an oncologic therapeutic plan and/or surgery to treat the diagnosed tumor; and (5) once the treatment plan is completed, the individual enters the follow-up protocol, which is monitored over time to see if the tumor has been completely removed or if instead it is still developing. Cervical cancer is undoubtedly the most successful example of a cancer screening campaign. Paradoxically, its effectiveness is one of the strongest reasons to criticize the usefulness of vaccination against human papillomavirus (HPV) in countries where the screening service with Pap test is organized in an efficient manner. Cervical cancer screening protocols are directed to sexually active women aged 25-64 years: they provide the Pap test performed by examining under a microscope or by staining with a specific “thin prep” the material taken from the cervix with a small spatula and a brush. It is recommended to repeat the test every two or three years. It is important to emphasize that women vaccinated against HPV must continue the screening with Pap test. Although some screening programs (e.g., Pap smears) have had remarkable success in reducing mortality from a specific cancer, any kind of screening is free from inherent limitations. The screening methods are in fact applied to large parts of the apparently healthy population. In particular, the limits for certain cancers may be as obvious as to prohibit the introduction of an organized screening program. Potential limitations of organized screenings are basically of two types: organizational and medical. The limits of organizational type relate to the ability of a program to recruit the whole target population. Although well organized, a screening program will hardly be able to exceed a coverage of 70%-80% of the target population, and in fact the results of the current programs are often much smaller. The limits of medical type are represented by the possibility of reducing the overall mortality, or specific mortality, using a specific screening campaign.

Immunoprevention of human papillomavirus-associated malignancies

Persistent infection by one of 15 high-risk human papillomavirus (hrHPV) types is a necessary but not sufficient cause of 5% of all human cancers. This provides a remarkable opportunity for cancer prevention via immunization. Since Harald zur Hausen's pioneering identification of hrHPV types 16 and 18, found in approximately 50% and 20% of cervical cancers, respectively, two prophylactic HPV vaccines containing virus-like particles (VLP) of each genotype have been widely licensed. These vaccines are beginning to affect infection and HPV-associated neoplasia rates after immunization campaigns in adolescents. Here, we review recent progress and opportunities to better prevent HPV-associated cancers, including broadening immune protection to cover all hrHPV types, reducing the cost of HPV vaccines especially for developing countries that have the highest rates of cervical cancer, and immune-based treatment of established HPV infections. Screening based upon George Papanicolaou's cervical cytology testing, and more recently detection of hrHPV DNA/RNA, followed by ablative treatment of high-grade cervical intraepithelial neoplasia (CIN2/3) have substantially reduced cervical cancer rates, and we examine their interplay with immune-based modalities for the prevention and eventual elimination of cervical cancer and other HPV-related malignancies.

Cancer chemoprevention: Much has been done, but there is still much to do. State of the art and possible new approaches

Over the past three decades great efforts have been made in search of cancer chemoprevention strategies. The increase in knowledge of the long process from normal to cancer cell has enabled interventions in terms of lifestyle modifications, natural compounds or drugs to block or reverse the process. Great successes have been achieved, especially for breast and colorectal cancer. However, these strategies have yet to find clinical application on a large scale. In this article we identify the achievements, the pitfalls and the next steps to be taken to improve the efficacy and applicability of chemoprevention strategies. Among the crucial key points to be implemented are educational activities for physicians to appropriately disseminate the aim and indeed the culture of chemoprevention. It is essential to improve the risk-benefit balance, seeking the minimal active doses, intermittent schedules, a better characterization of the risk categories via a more personalized intervention based on individual characteristics, and ensure the containment of costs of public and private health prevention programs.

Expression of HPV-16 L1 capsomeres with glutathione-S-transferase as a fusion protein in tobacco plastids: an approach for a capsomere-based HPV vaccine

Human Papillomavirus (HPV) is the main cause of cervical cancer, which is the second most severe cancer of women worldwide, particularly in developing countries. Although vaccines against HPV infection are commercially available, they are neither affordable nor accessible to women in low income countries e.g. Africa. Thus, alternative cost-effective vaccine production approaches need to be developed. This study uses tobacco plants to express pentameric capsomeres of HPV that have been reported to generate elevated immune responses against HPV. A modified HPV-16 L1 (L1_2xCysM) protein has been expressed as a fusion protein with glutathione-S-transferase (GST) in tobacco chloroplasts following biolistic transformation. In total 7 transplastomic lines with healthy phenotypes were generated. Site specific integration of the GST-L1_2xCysM and aadA genes was confirmed by PCR. Southern blot analysis verified homogenous transformation of all transplastomic lines. Antigen capture ELISA with the conformation-specific antibody Ritti01, showed protein expression as well as the retention of immunogenic epitopes of L1 protein. In their morphology, GST-L1 expressing tobacco plants were identical to wild type plants and yielded fertile flowers. Taken together, these data enrich knowledge for future development of cost-effective plant-made vaccines against HPV.

HPV testing with cytology triage for cervical cancer screening in routine practice

OBJECTIVE

The purpose of this study was to evaluate the feasibility and effectiveness of Viral Testing Alone with Pap (Papanicolaou) Triage for Screening Cervical Cancer in Routine Practice (VASCAR) in a publicly funded university-affiliated hospital in Montreal, Canada.

STUDY DESIGN

Women who are 30-65 years old are screened with the Hybrid Capture-2 assay. Women with negative results are retested at 3-year intervals; women with positive results are triaged with conventional cytologic methods. Women with Papanicolaou positive test results (≥atypical squamous cells of undetermined significance) are referred to colposcopy; women with Papanicolaou negative test results are retested with Hybrid Capture-2 assay and a Papanicolaou test in 1 year. Results were compared with a historic era (annual cytology with ≥atypical squamous cells of undetermined significance threshold for colposcopy referral) in the 3 years before VASCAR.

RESULTS

VASCAR included 23,739 eligible women, among whom 1646 women (6.9%) tested positive for the human papillomavirus (HPV). Because of the need for subsequent sampling for cytologic testing, follow-up evaluation for cytologic triage was relatively poor; only 46% and 24% of HPV-positive women were Papanicolaou-triaged and underwent biopsy, respectively. Protocol violations occurred mainly in the early phases of implementation (12%). Detection of high-grade cervical intraepithelial neoplasia increased nearly 3-fold (rate ratio, 2.78; 95% confidence interval [CI], 2.1-3.7) during VASCAR, mostly because of a doubling in the rate of high-grade cervical intraepithelial neoplasia (34.0%; 95% CI, 21.2-48.8) compared with the historic cytology-only era (16.3%; 95% CI, 13.2-19.8). VASCAR reduced the median time to colposcopy from a positive screen from 11 months (95% CI, 10.48-11.50) to 3 months (95% CI, 2.64-3.80).

CONCLUSION

VASCAR is feasible; however, it requires cosampling for HPV and cytology and for continuous education of healthcare providers of the HPV-Papanicolaou triage protocol. Efficacy in disease detection and reduction in time to colposcopy referrals compared with the historic cytology era is encouraging but should be considered preliminary because of the small number of patients who were tested.

Prevalence and distribution of high-risk human papillomavirus genotypes in invasive carcinoma of the uterine cervix in Uruguay

OBJECTIVES

Persistent infection with specific genotypes of human papillomaviruses (HPVs) is the main cause of invasive cervical cancer (ICC). Only a few of the various HPV types account for most of the cases worldwide, and geographical differences in their distribution are evident. Data from locally prevalent genotypes are essential in view of introduction of HPV type-specific prophylactic vaccines.

METHODS

In this work, we have investigated HPV type distribution in samples of ICC cases that occurred in Uruguayan women. DNA extracted from ICC treated in Centro Hospitalario Pereira Rossell of Montevideo between 1999 and 2007 were analyzed. Search and typing were performed by polymerase chain reaction using generic GP5+/GP6+ primers and specific primers for HPV types 16, 18, 33, and 45. Positive GP5+/GP6+ samples, which were negative for all 4 high-risk HPV-specific types screened were further analyzed by sequencing.

RESULTS

Human papillomavirus DNA sequences were found in 163 (92.6%) of 176 cases. The most prevalent genotypes were HPV16 (67.6%) and HPV18 (8.5%) followed by HPV45 (6.8%) and HPV33 (3.4%), as single or mixed infection. Other less frequent genotypes were HPV31, HPV35, HPV39, HPV51, HPV52, HPV58, HPV66, and HPV73. The viral type could not be determined (HPV X) in 1 case (0.6%) of the HPV DNA-positive cervical cancers and double infections were found in 1.7% of the cases. The higher percentage of most aggressive HPV (16/18/45) genotypes was detected in cases diagnosed at younger than 60 years old, whereas these genotypes were less frequent in older patients.

CONCLUSION

We conclude that HPV types 16, 18, and 45 have a very high prevalence in ICC of Uruguayan women. Results provide evidence that 16 of 18 infections are more aggressive, but most cancers could be vaccine preventable.

Multiple infections and cancer: implications in epidemiology

Approximately 18% of the global cancer burden has been attributed to infectious agents, with estimates ranging from 7% in developed countries to about 22% in developing countries. Chronic infections caused by the hepatitis B and C viruses, human papilloma viruses (HPV), and Helicobacter pylori (H. pylori) are reported to be responsible for approximately 15% of all human cancers. Interestingly, although many of the infectious agents that have been associated with cancer--such as HPV, Epstein-Barr virus (EBV), and H. pylori--are highly prevalent in the world, most infected individuals do not develop cancer but remain lifelong carriers. Malignancies associated with infectious agents may result from prolonged latency as a result of chronic infections. Pathogenic infections are necessary but are not sufficient for cancer initiation or progression. Cancer initiation may require additional cofactors, including secondary infections. Therefore, in patients with chronic infection with one agent, secondary co-infection with another agent may serve as an important co-factor that may cause cancer initiation and progression. Additionally, opportunistic co-infections could significantly inhibit response to cancer treatment and increase cancer mortality. Co-infections are relatively common in areas with a high prevalence of infectious agents, especially in developing countries. These co-infections can cause an imbalance in the host immune system by affecting persistence of and susceptibility to malignant infections. Several articles have been published that focus on infectious agents and cancer. In this article, we discuss the role of infectious agents in malignancies, highlight the role of multiple/co-infections in cancer etiology, and review implications for cancer epidemiology.

Potential use of vaccines in the primary prevention of breast cancer in high-risk patients

Cancer vaccines are an emerging therapeutic and prophylactic modality that may play a more important role in cancer prevention and treatment in the future. Therapeutic cancer vaccines are designed to generate a targeted, immune-mediated antitumor response. Successful prophylactic vaccines are those against oncogenic viral infections, such as the human papillomavirus and cervical cancer. However, a tough challenge for the majority of tumor vaccines is the self-nature of tumor antigens. Ongoing studies are investigating methods to enhance vaccine strategies including immune-modulating agents. The present review analyzes the potential use of vaccines in the primary prevention of breast cancer, focusing on the recent extension of vaccine target selection to self-proteins that are overexpressed during the early stages of tumor development but whose expression no longer occurs as we age, a feature that may avoid clinically significant autoimmune sequelae.

HPV vaccination and cervical cancer

Cervical cancer is the third most common cancer in women worldwide and often affects women under 40 years with young families. Vaccination against the human papillomavirus (HPV) is a major advance, since it offers primary prevention against the infectious agent that is the main cause of the disease. Two prophylactic vaccines have shown great promise in clinical trials. One of these (Gardasil(®)) contains all four HPV types, offering protection against genital warts (types 6 and 11) as well as cervical cancer (types 16 and 18). The other (Cervarix(®)) contains types 16 and 18, targeting cervical cancer alone, but also has a degree of cross-protection against types 31 and 45, which could significantly increase the level of protection. Adolescent girls remain the primary target of vaccination programmes, but the issues of vaccinating boys and older women are increasingly debated.

Reframing cervical cancer prevention. Expanding the field towards prevention of human papillomavirus infections and related diseases

The reframed paradigm of cervical cancer prevention will include strategic combinations of at least four major components: 1) routine introduction of human papillomavirus (HPV) vaccines to women in all countries, 2) extension and simplification of existing screening programs using HPV-based technology, 3) extension of adapted screening programs to developing populations, and 4) consideration of the broader spectrum of cancers and other diseases preventable by HPV vaccination in women, as well as in men. On a global scale, vaccination of newborns and infants is well established and has developed a successful working infrastructure. The hepatitis B virus (HBV) vaccination programs offer a model for HPV introduction in which newborn and infant immunization achieves a rapid reduction in the prevalence of the HBV carrier rates in immunized cohorts of children, and of liver cirrhosis and liver cancer decades later. In contrast, screening for cervical pre-cancer is largely restricted to industrialized populations and upper social classes in developing countries. The expertise gained by vaccination programs worldwide needs to be coordinated with the traditional cervical cancer prevention community of gynecologists and pathologists. Significant political and advocacy efforts at the Global level (World Health Organization, other United Nations agencies and The GAVI Alliance) need to be organized and reinforced to achieve a meaningful reduction in HPV transmission and its related health conditions and cancers. This desirable goal is now scientifically and technologically attainable, and great progress is being made in obtaining financing for global HPV immunization. This article forms part of a special supplement entitled "Comprehensive Control of HPV Infections and Related Diseases" Vaccine Volume 30, Supplement 5, 2012.

Incidence and cost of anal, penile, vaginal and vulvar cancer in Denmark

Background

Besides being a causative agent for genital warts and cervical cancer, human papillomavirus (HPV) contributes to 40-85% of cases of anal, penile, vaginal and vulvar cancer and precancerous lesions. HPV types 16 & 18 in particular contribute to 74-93% of these cases. Overall the number of new cases of these four cancers may be relatively high implying notable health care cost to society. The aim of this study was to estimate the incidence and the health care sector costs of anal, penile, vaginal and vulvar cancer.

Methods

New anogenital cancer patients were identified from the Danish National Cancer Register using ICD-10 diagnosis codes. Resource use in the health care sector was estimated for the year prior to diagnosis, and for the first, second and third years after diagnosis. Hospital resource use was defined in terms of registered hospital contacts, using DRG (Diagnosis Related Groups) and DAGS (Danish Outpatient Groups System) charges as cost estimates for inpatient and outpatient contacts, respectively. Health care consumption by cancer patients diagnosed in 2004–2007 was compared with that by an age- and sex-matched cohort without cancer. Hospital costs attributable to four anogenital cancers were estimated using regression analysis.

Results

The annual incidence of anal cancer in Denmark is 1.9 per 100,000 persons. The corresponding incidence rates for penile, vaginal and vulvar cancer are 1.7, 0.9 and 3.6 per 100,000 males/females, respectively. The total number of new cases of these four cancers in Denmark is about 270 per year. In comparison, the total number of new cases cervical cancer is around 390 per year. The total cost of anogenital cancer to the hospital sector was estimated to be 7.6 million Euros per year. Costs associated with anal and vulvar cancer constituted the majority of the costs.

Conclusions

Anogenital cancer incurs considerable costs to the Danish hospital sector. It is expected that the current HPV vaccination program will markedly reduce this burden.

Relationship of zolpidem and cancer risk: a Taiwanese population-based cohort study

OBJECTIVE

To evaluate the relationship between the use of zolpidem and subsequent cancer risk in Taiwanese patients.

METHODS

We used data from the National Health Insurance system of Taiwan to investigate whether use of zolpidem was related to cancer risk. For the study cohort, we identified 14,950 patients who had received a first prescription for zolpidem from January 1, 1998, through December 31, 2000. For each zolpidem user, we selected randomly 4 comparison patients without a history of using zolpidem who were frequency-matched by sex, age, and year of the index date. Incidence rates of all cancers and selected site-specific cancers were measured by the end of 2009, and related hazard ratios (HRs) and 95% confidence intervals (CIs) of the cancer were measured as well.

RESULTS

The risk of developing any cancer was greater in patients using zolpidem than in nonusers (HR, 1.68; 95% CI, 1.55-1.82). The stratified analysis showed that the overall HR for high-dosage zolpidem (≥300 mg/y) was 2.38. The site-specific cancer risk was the highest for oral cancer (HR, 2.36; 95% CI, 1.57-3.56), followed by kidney cancer, esophageal cancer, breast cancer, liver cancer, lung cancer, and bladder cancer (HR, 1.60; 95% CI, 1.06-2.41). Men were at higher risk than women.

CONCLUSION

This population-based study revealed some unexpected findings, suggesting that the use of zolpidem may be associated with an increased risk of subsequent cancer. Further large-scale and in-depth investigations in this area are warranted.