Environmental co-factors in HPV carcinogenesis

Covariates of cervical cytokine mRNA expression by real-time PCR in adolescents and young women: effects of Chlamydia trachomatis infection, hormonal contraception, and smoking

Measurements of mucosal immune parameters in the uterine cervix are potentially influenced by numerous factors, including infections, endogenous and exogenous hormones, semen, and nicotine and its metabolites in cervical mucus. The objective of this study was to examine correlates of immunoregulatory cytokine mRNA expression in cervical cytology samples in a cross-sectional design. Samples, collected at study entry by cervical cytology brush from 368 women aged 13-21 enrolled in a longitudinal study of the natural history of human papillomavirus (HPV) infection, were tested by quantitative RT-PCR for expression of IFN-gamma, IL-4, IL-10, and IL-12. In a multivariate analysis, elevated levels of IFN-gamma, IL-10, and IL-12 were significantly (p < 0.05) associated with several variables, including current C. trachomatis infection, recent intercourse, and current oral contraceptive pill use. Suppressed IL-4 and IL-10 levels were associated with cigarette smoking within the last 24 h. Time since last menstrual period did not affect any of the cytokines; in a substudy of weekly cytokine variability, however, IL-10 showed a non-significant trend toward higher levels around the time of menstruation.

Worldwide human papillomavirus etiology of cervical adenocarcinoma and its cofactors: implications for screening and prevention

BACKGROUND

Most cancers of the uterine cervix are squamous cell carcinomas. Although the incidence of such carcinomas of the uterine cervix has declined over time, that of cervical adenocarcinoma has risen in recent years. The extent to which human papillomavirus (HPV) infection and cofactors may explain this differential trend is unclear.

METHODS

We pooled data from eight case-control studies of cervical cancer that were conducted on three continents. A total of 167 case patients with invasive cervical adenocarcinoma (112 with adenocarcinoma and 55 with adenosquamous carcinoma) and 1881 hospital-based control subjects were included. HPV DNA was analyzed in cervical specimens with the GP5+/6+ general primer system followed by type-specific hybridization for 33 HPV genotypes. Blood samples were analyzed for chlamydial and herpes simplex virus 2 (HSV-2) serology. Multivariable unconditional logistic regression modeling was used to calculate odds ratios (ORs) with 95% confidence intervals (CIs). All tests of statistical significance were two-sided.

RESULTS

The adjusted overall odds ratio for cervical adenocarcinoma in HPV-positive women compared with HPV-negative women was 81.3 (95% CI = 42.0 to 157.1). HPV 16 and HPV 18 were the two most commonly detected HPV types in case patients and control subjects. These two types were present in 82% of the patients. Cofactors that showed clear statistically significant positive associations with cervical adenocarcinoma overall and among HPV-positive women included never schooling, poor hygiene, sexual behavior-related variables, long-term use of hormonal contraception, high parity, and HSV-2 seropositivity. Parity had a weaker association with adenocarcinoma and only among HPV-positive women. Use of an intrauterine device (IUD) had a statistically significant inverse association with risk of adenocarcinoma (for ever use of an IUD compared with never use, OR = .41 [95% CI = 0.18 to 0.93]). Smoking and chlamydial seropositivity were not associated with disease.

CONCLUSIONS

HPV appears to be the key risk factor for cervical adenocarcinoma. HPV testing in primary screening using current mixtures of HPV types and HPV vaccination against main HPV types should reduce the incidence of this cancer worldwide.

The development of cervical cancer and its precursors: what is the role of human papillomavirus infection?

Human papillomavirus (HPV) is a significant health care burden in the United States. The majority of sexually active men and women will be infected with HPV at some point in their lives and are subject to developing human papillomavirus-associated disease. Current estimates suggest that 20 million Americans are currently infected, and more than 5 million new infections occur each year. The prevalence of human papillomavirus is highest in populations in their late teens and early twenties, with nearly half of all new human papillomavirus infections occurring within 3 years of first intercourse. HPV is the necessary cause of genital warts, cervical intraepithelial neoplasia, and invasive cervical cancer. As such, human papillomavirus is responsible for significant medical morbidity and health care costs. Screening with cervical cytology has significantly reduced mortality rates; however, approximately 3900 women will die in 2005 from cervical cancer in the United States. Human papillomavirus DNA testing has shown promise in identifying high-grade abnormalities as an adjunct to traditional cytology, and should be used according to guidelines established by the American Cancer Society and the American College of Obstetricians and Gynecologists. The epidemiology of HPV infection and a brief introduction to the natural history of HPV infection will be presented here.

Cervical cancer and CYP2E1 polymorphisms: implications for molecular epidemiology

INTRODUCTION

Besides human papillomavirus (HPV) infection, several cofactors are considered important for the development of cervical cancer (CC). Among these, tobacco smoke, other sexually transmitted diseases, inflammation and nutritional factors have been intensively described. CYP2E1 polymorphisms have been associated with the metabolization of several carcinogens, some of them considered risk factors for CC development, such as tobacco smoke. The aim of this study was to evaluate the role of CYP2E1 polymorphisms in the susceptibility to cervical cancer in a Portuguese population.

PATIENTS AND METHODS

The genotypic analysis was performed with the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology, using peripheral blood samples of 454 individuals: 122 presented invasive squamous cell carcinoma (ICC), 59 presented squamous intraepithelial lesions (SIL), and the control population was composed of 274 healthy individuals.

RESULTS

Concerning the DraI polymorphism, we observed a decreased risk for the development of squamous cervical lesions in the presence of the C allele [odds ratio (OR)=0.600; 0.378<OR<0.952; p=0.029]. In the stratification of the analysis according to the mean age, we observed an increased risk for the development of SIL, for women older than 39 years of age, in the presence of the D allele (OR=0.087; 0.012<OR<0.651; p=0.003). Regarding the RsaI polymorphism, we did not find any significant differences.

CONCLUSION

The decreased risk observed for the development of SIL and not ICC in the presence of the D allele may indicate that CYP2E1 interferes with the initial steps of the carcinogenic process, probably due to its involvement in the action of immunological mediators, expressed during cervical inflammation. These aspects may help to define new therapeutic strategies for chemoprevention.

[Is early first intercourse a risk factor for cervical cancer?]

Sexual behavior has long been known to be a risk factor for cervical carcinoma. Certain sexual risk factors are related to an increased risk of chronic infection of the cervical transformation zone with high-risk human papilloma viruses (HPVs). Numerous retrospective analyses consider early first intercourse a probable risk factor for later development of cervical carcinoma. Since risk factors are associated, it is unclear whether early first intercourse is an independent risk factor for cervical neoplasia. Few comprehensive retrospective studies are available. It is possible that the cervical transformation zone is particularly vulnerable to infection between menarche and the age of sixteen. During this phase there are a large number of undifferentiated cells at the periphery of the metaplasia, practically at the surface of the cervix. It seems that this area is particularly susceptible to HPV infection. There are also indications that there is no secondary immune response to HPV at the time of early first intercourse, making the immune response to HPV less efficient. Other possible risk factors for cervical cancer include genetic predisposition, nutrition, smoking, Chlamydia or HSV-2 infections, drug abuse, oral contraception, immune suppression and early first pregnancy. Education appears important to encourage responsible sexual behaviour in young people.

Quality of life and mental health in cervical and endometrial cancer survivors

OBJECTIVES

The goal of this study was to examine quality of life and mood in long-term survivors of cervical and endometrial cancer. Relationships of quality of life and mood with demographic and disease factors were also investigated.

METHODS

One-hundred fifty-two survivors of cervical or endometrial cancer diagnosed and treated 5-20 years ago at the University of Iowa Hospitals and Clinics participated. Eighty-nine healthy controls were recruited from a hospital gynecology clinic. Quality of life, mood, and demographics were assessed by questionnaires. Disease characteristics of cancer survivors were abstracted from medical records.

RESULTS

There were no significant differences in quality of life or depressive symptoms between the three groups. Cervical cancer survivors reported significantly more anxiety than endometrial cancer survivors, and more dysphoria, anger, and confusion than either endometrial cancer survivors or healthy controls. Greater depression and mood disturbance were reported by unemployed and unmarried cancer survivors. Treatment modality, stage of disease, and length of time since diagnosis were not related to quality of life or mood.

CONCLUSIONS

Quality of life in cervical and endometrial cancer survivors approximates that of healthy controls by 5 years post-diagnosis. However, cervical cancer survivors report more negative mood than survivors of endometrial cancer or healthy controls. Cancer survivors who are unemployed or living alone may be especially at risk for mood and mental health difficulties.

Association of tumor necrosis factor a-2 and a-8 microsatellite alleles with human papillomavirus and squamous intraepithelial lesions among women in Brazil

Infection with oncogenic human papillomavirus (HPV) is considered to be the major risk factor for cervical cancer. Tumor necrosis factor (TNF) is a pluripotent cytokine that plays an important role in inhibiting the action of microbial agents, and TNF microsatellite polymorphisms have been associated with several diseases, including cancer and viral infections. This study analyzed the associations between TNFa to -e microsatellite polymorphisms and the severity of squamous intraepithelial lesions (SIL), according to the presence of the oncogenic HPV16 and HPV18 types. Samples from 146 HPV-positive women with low-grade SIL (LSIL) and high-grade SIL (HSIL) and samples from 101 healthy women were studied. TNF microsatellite polymorphism typing and HPV detection and typing were performed using PCR-amplified DNA hybridized with sequence-specific primers. Data were analyzed by Fisher's exact test using the GENEPOP software. Significant associations were observed between LSIL and the TNFa-8 allele (4/166; P = 0.04), as well as between TNFa-2 with HPV18 only (16/44; P = 0.002) and TNFa-2 with HPV18 coinfection with HPV16 (16/44; P = 0.001). Patients exhibiting the TNFa-2 allele and harboring HPV18, in the presence or absence of coinfection with HPV16, had an increased risk of HSIL occurrence (13/38; P = 0.04; 5/10; P = 0.04) compared to patients with other HPV types. These results suggest that the TNFa-8 allele is associated with increased susceptibility to the occurrence of LSIL and that despite the presence of a high TNF-alpha production allele, the ability of HPV18 to resist the inhibitory effects of TNF-alpha may contribute to the occurrence of infection and consequently to HSIL in women with cervical HPV18 infection.

[Contribution of viral typing in cytological anomalies of the cervix]

Management practices for low-grade cervical lesions identified on screening swabs have been modified by research on the HPV. The appropriate approach for low-grade lesions is particularly difficult to determine due to the potential risk of malignant transformation coupled with the cost implications of treating lesions which will heal spontaneously in the majority of patients. The diagnosis of these low-grade lesions can be improved by thin layer swabs which have a greater sensitivity than conventional swabs. The current consensus is that swab results should be expressed according to the Bethesda classification. Routine tests for HPV (Hybrid Capture II) should be reserved for patients with an ASC-US swab. Colposcopy is indicated if the swab is positive for a low-grade lesion followed by cytology if the colposcopy is normal. If there is no evidence of HPV, search for oncogenes can lighten the treatment regimen due to the high specificity of the test. If a low-grade histological lesion (CIN1) is proven, cytocolposcopic surveillance should be proposed, surgical resection being undertaken in colposcopy cannot be performed. Here again search for HPV oncogenes at one year is an interesting alternative if the examination is negative. These practices are applicable in adolescents and HIV- positive patients who are particularly exposed to HPV.

Human papillomavirus type and tobacco use as predictors of survival in early stage cervical carcinoma

OBJECTIVE

Molecular and environmental co-factors are known risk factors for cervical cancer. The aim of this study was to define the prognostic significance of HPV 18 and its phylogenetically related viruses and smoking on survival in patients with early stage cervical cancer.

METHODS

HPV typing was performed on stage IB-IIB cervical tumors. Subjects positive for HPV 18 or 45 were compared to the remainder of the cohort and to women with tumors containing HPV 16, 31, or 52. Tobacco use was ascertained by patient questionnaire.

RESULTS

Tumors of 255 women were evaluated. The presence of HPV 18 or 45 was associated with decreased survival. In a multivariable Cox proportional hazards analysis comparing patients with HPV 18 or 45 containing tumors to the rest of the cohort, the hazard ratio for death from cervical cancer was 2.08 (95% CI, 1.07-4.04). The hazard ratio for death from cervical cancer was 2.41 (95% CI, 1.17-4.96) when the HPV 18 and 45 group was compared to women with HPV 16 or its related viruses, 31 and 52. Smoking was associated with a decreased survival for women with HPV 18 or 45, even after adjusting for other known prognostic factors (P = 0.031).

CONCLUSIONS

In addition to pathologic indicators, molecular and environmental co-factors are important determinates of outcome in early stage cervical cancer. The presence of HPV 18 or 45 is associated with a decreased survival. The adverse effect of HPV 18 and 45 on survival is compounded by tobacco use.

Pain predicts non-adherence to pap smear screening among middle-aged African American women

BACKGROUND

Middle-aged African American women have the highest incidence and mortality of invasive cervical cancer in the United States and the lowest adherence to pap smear screening.

METHODS

In 2001, we identified factors associated with non-adherence to screening recommendations using three focus group interviews and subsequently developed a questionnaire administered to 144 African American women aged 45 to 65 years.

RESULTS

The perception that the Pap test was painful was associated with non-adherence to screening recommendations (OR = 4.78; 95%CI: 1.67-13.7). Difficulty to pay for the office visit coupled with perceived pain was associated with a nearly sixfold increase in risk of non-adherence (OR = 5.8; 95%CI: 2.8-15.5). Previously identified barriers to screening including lower education and socioeconomic status, poor access to care, knowledge of and exposure to known risk factors of invasive cervical cancer, cancer fatalism, and perceived racism were not independently associated with non-adherence.

CONCLUSIONS

These data suggest that, among middle-aged African American women, future interventions addressing pain during a Pap test will likely increase acceptability of and adherence to cervical cancer screening. Pain could be addressed either by providing information during the pap test and/or using smaller lubricated speculums.

Modifiable Risk Factors Associated with Clearance of Type-Specific Cervical Human Papillomavirus Infections in a Cohort of University Students

BACKGROUND

Previous findings regarding risk factors for human papillomavirus (HPV) persistence, other than viral determinants, identified from prospective cohort studies have been inconsistent in part because study designs have differed with respect to differing HPV detection methods and varying lengths of follow-up time. Therefore, the objectives of this study were to continue the search for epidemiologic risk factors of persistent cervical HPV infections and determine what behaviors differed between those women with transient HPV infections and those women who cannot clear their type-specific HPV infections.

METHODS

Female university students (n = 621) in Montreal were followed for 24 months at 6-month intervals. At each visit, a cervical cell specimen was collected. HPV DNA was detected using the MY09/MY11 PCR protocol and 27 HPV genotypes were identified by the line blot assay (Roche Molecular Systems, Inc., Alameda, CA). Proportional hazards regression was used to estimate the crude and adjusted hazard ratios of clearing a type-specific high-risk (n = 222) or low-risk (n = 105) HPV infection over time according to specific baseline and time-dependent covariates.

RESULTS

Daily consumption of vegetables seemed to increase the rate of HPV clearance independent of type. The use of tampons was associated with a reduced rate of high-risk HPV clearance, whereas regular condom use was associated with an increased rate of low-risk HPV clearance only.

CONCLUSION

Some proactive measures can be taken to increase the rate of HPV clearance, and there may be some differences between the sets of predictors of low-risk and high-risk HPV clearance.

Rel/Nuclear factor-kappa B apoptosis pathways in human cervical cancer cells

Cervical cancer is considered a common yet preventable cause of death in women. It has been estimated that about 420 women out of the 1400 women diagnosed with cervical cancer will die during 5 years from diagnosis. This review addresses the pathogenesis of cervical cancer in humans with a special emphasis on the human papilloma virus as a predominant cause of cervical cancer in humans. The current understanding of apoptosis and regulators of apoptosis as well as their implication in carcinogenesis will follow. A special focus will be given to the role of Rel/NF-kappaB family of genes in the growth and chemotherapeutic treatment of the malignant HeLa cervical cells emphasizing on Xrel3, a cRel homologue.

Incidence, age at onset, and potential reasons of malignant transformation in recurrent respiratory papillomatosis patients: 20 years experience

Forty-two patients with recurrent respiratory papillomatosis (RRP) were accepted into a multicenter prospective study in 1983 to 1990, treated with alfa-IFN 3 MU/m 2 3 times a week and then followed-up until August 1, 2003. All the patients who had disease progression with pulmonary spread were characterized by insufficient response to IFN-therapy and detection of HPV type 11. Five patients (4/5 smokers) presented malignant transformation in lungs or nasopharynx (mean RRP duration was 27.2 +/- 8 years from RRP onset and 14.6 +/- 6.3 years from pulmonary spread until malignant transformation) with persistent RRP in larynx. The results of long-term follow-up in RRP patients with HPV 11 underline the necessity of reanalyzing the current therapy.

Downregulation of calcineurin activity in cervical carcinoma

BACKGROUND: Calcineurin (CaN) is an important serine-threonine phosphatase (PP2B), which plays a crucial role in calcium-calmodulin mediated signal transduction events. Calcineurin has been implicated in pathogenesis of various diseases cardiac hypertrophy, diabetic neuropathy and Alzheimer's, however its role in neoplasia remains unclear. RESULTS: In view of this we evaluated the calcineurin activity in serum and biopsy samples collected from women diagnosed with invasive squamous cell carcinoma of cervix. A significant reduction was observed in the calcineurin activity in cancer cervix patients compared to the control group. However the calcineurin activity remained unaltered in the cervical scrapes obtained from patients diagnosed with low-grade squamous intra epithelial lesions (LSIL). Interestingly the downregulation of calcineurin activity in squamous cell carcinomas was not accompanied by any significant change in DNA-binding affinity of the transcriptional factor NFAT (Nuclear Factor of Activated T-cells). All the squamous cell carcinoma samples used in the present study were positive for high-risk human papillomavirus (HPV) types. CONCLUSION: The present study demonstrates the downregulation of calcineurin activity in squamous cell carcinoma of cervix with high risk HPV infection. We conclude that perturbations in calcineurin-mediated pathway may be involved in development of cervical neoplasia.

Evidence for practice: oral contraception and risk of cervical cancer

PURPOSE

The issue of continued oral contraceptive use among women with abnormal Pap smears may be controversial due to reported evidence of an increased risk of cervical cancer among long term oral contraceptive users. This article reviews the evidence concerning oral contraception and cervical cancer risk. The role of Human Papilloma virus (HPV) and proposed mechanisms for the development of cervical cancer are explained. Evidence from World Health Organization (WHO) studies and additional research evidence are discussed. Implications for clinical practice are included.

DATA SOURCES

WHO commissioned studies, additional relevant studies searchable from an EBSCO database, and texts that describe the natural history of HPV.

CONCLUSIONS

Epidemiological studies and biomedical research suggest a role for steroid hormones, such as oral contraceptives, in facilitating the action of HPV. However, a majority of HPV infections resolve spontaneously, despite widespread use of oral contraception. Oral contraception does not appear to increase incident HPV infection or persistence of HPV infection. The benefits of oral contraceptives appear to outweigh the risks associated with HPV facilitation.

IMPLICATIONS FOR PRACTICE

NPs inform patients of abnormal Pap smears, manage the clinical care of women at risk of cervical cancer, and provide educational counseling regarding contraceptive choices. Ethical considerations include clear disclosure of potential risk. However, a risk-benefit analysis supports continued use of oral contraception among women who have abnormal Pap smears but also have access to clinical surveillance.

E5 protein of human papillomavirus type 16 selectively downregulates surface HLA class I

Papillomaviruses have evolved mechanisms that result in escape from host immune surveillance. The E5 protein is expressed early in papillomavirus infection in the deep layers of the infected epithelium. It is localized to the Golgi apparatus (GA) and endoplasmic reticulum. The E5 protein of bovine papillomavirus (BPV) impairs the synthesis and stability of major histocompatibility (MHC) class I complexes and prevents their transport to the cell surface due to retention in the GA. Here we show that human papillomavirus type 16 (HPV-16) E5 also causes the retention of MHC (HLA) class I complexes in the GA and impedes their transport to the cell surface, which is rescued by treatment with interferon. Unlike BPV E5, HPV-16 E5 does not affect the synthesis of HLA class I heavy chains or the expression of the transporter associated with antigen processing TAP. These results show that downregulation of surface MHC class I molecules is common to both BPV and HPV E5 proteins. Moreover, we determined that HPV-16 E5 downregulates surface expression of HLA-A and HLA-B, which present viral peptides to MHC class I-restricted cytotoxic T lymphocytes (CTLs), but not the natural killer (NK) cell inhibitory ligands HLA-C and HLA-E. Selective downregulation of cell surface HLA class I molecules may allow the virus to establish infection by avoiding immune clearance of virus-infected cells by both CTLs and NK cells.

Epidemiologic correlates of cervical human papillomavirus prevalence in women with abnormal Pap smear tests: A Taiwan cooperative oncology group (TCOG) study

To explore factors affecting human papillomavirus (HPV) prevalence in all grades of cervical neoplasia among Chinese women, 1,264 women with abnormal cervical cytology attending the gynaecologic clinics of 11 major medical centres in Taiwan. Patients were interviewed and underwent complete gynaecologic examination including colposcopy. Cervical scrapings were collected for HPV DNA detection by both Hybrid Capture-2 (high-risk probe) and L1 consensus PCR-reverse line blot. The prevalences of HPV in the four different diagnosis groups: (i) suspicious (n = 316), (ii) low-grade intraepithelial lesion (n = 474), (iii) high-grade intraepithelial lesion (n = 450), and (iv) cancer (n = 16), were 36.1%, 74.7%, 83.6%, and 100%, respectively. In the latter two groups, Patients less than 30 or 40 years old, respectively, tended to be infected more frequently with HPV than the older patients were. The main correlates of HPV prevalence were lifetime number of sex partners (odds ratio (OR) for two or more partners: 2.44; 95% CI, 1.44-4.15), vaginal douching after intercourse (OR for douching frequently: 1.44; 95% CI, 1.01-2.04), vitamin supplementation (OR for regular vitamin supplement: 0.71, 95% CI, 0.55-0.92), and performance of Pap smear tests (OR for never having a Pap smear performed: 2.22; 95% CI, 1.19-4.17). The risk for vaginal douching was augmented by the promiscuity of sex partners (OR of 3.19 (1.91-5.34)) and smoking (OR of 1.90 (1.15-3.13)), whereas vitamin supplementation reduced the odds ratio to 1.35 (0.85-2.15). The results of this study provide further evidence of the role of HPV in cervical carcinogenesis. The data also indicate the main areas of risk for the prevalence of HPV in cervical neoplasia in Chinese women living in Taiwan.

Human papillomavirus type 16 in head and neck carcinogenesis

The aetiology of squamous cell carcinomas of the head and neck (HNSCC) is multifactorial. Oncogenic human papillomaviruses (HPVs), a causative agent in uterine cervical cancer, have also been repeatedly detected in HNSCC, especially in squamous cell carcinomas of tonsils. Approximately half the HPV DNA-positive HNSCC contain detectable E6/E7 transcripts with wild-type p53, reduced pRb and overexpressed p16 in the tumours. HPV-16 is the predominant type and exists in episomal, integrated, or mixed forms. Tonsillar carcinomas have a remarkably higher viral load than carcinomas at other sites of the head and neck region. HPV-16 DNA has also been detected in tumour-free tonsils. Infection by oncogenic HPVs is a necessary but not a sufficient cause of cancers. Studies on the molecular mechanisms underlying HPV-associated carcinogenesis are difficult, because HPV is not easy to propagate in vitro. HPV-immortalised human tonsillar epithelial cell lines may provide an in vitro model to study co-factors for the HPV-associated tonsillar cancers and to test the effects of anti-viral and anti-tumour agents.

Friends or foes - bipolar effects of the tumour stroma in cancer

The restricted view of tumour progression as a multistep process defined by the accumulation of mutations in cancer cells has largely ignored the substantial contribution of the tumour microenvironment to malignancy. Even though the seed and soil hypothesis of Paget dates to 1889, it has been less than two decades since researchers have included the tumour microenvironment in their analyses of tumour progression. What have we recently learned from studying tumour-stroma interactions, and will this help to define new targets for therapy?

The cervical cancer epidemic that screening has prevented in the UK

BACKGROUND

Recent reports suggest that the reduction in mortality achieved by the UK national cervical screening programme is too small to justify its financial and psychosocial costs, except perhaps in a few high-risk women.

METHODS

We analysed trends in mortality before 1988, when the British national screening programme was launched, to estimate what future trends in cervical cancer mortality would have been without any screening.

FINDINGS

Cervical cancer mortality in England and Wales in women younger than 35 years rose three-fold from 1967 to 1987. By 1988, incidence in this age-range was among the highest in the world despite substantial opportunistic screening. Since national screening was started in 1988, this rising trend has been reversed.

INTERPRETATION

Cervical screening has prevented an epidemic that would have killed about one in 65 of all British women born since 1950 and culminated in about 6000 deaths per year in this country. However, these estimates are subject to substantial uncertainty, particularly in relation to the effects of oral contraceptives and changes in sexual behaviour. 80% or more of these deaths (up to 5000 deaths per year) are likely to be prevented by screening, which means that about 100000 (one in 80) of the 8 million British women born between 1951 and 1970 will be saved from premature death by the cervical screening programme at a cost per life saved of about pound 36000. The birth cohort trends also provide strong evidence that the death rate throughout life is substantially lower in women who were first screened when they were younger.

Distribution of human papillomavirus type 16 variants in human immunodeficiency virus type 1-positive and -negative women

The prevalence of human papillomavirus type 16 E6 variant lineages was characterized in a cross-sectional study of 24 human immunodeficiency virus type 1 (HIV)-positive and 33 HIV-negative women in New Orleans. The European prototype was the predominant variant in the HIV-negative women (39·4 %), while in the HIV-positive women the European 350G variant was predominant (29·1 %). In exact logistic regression models, HIV-positive women were significantly more likely to harbour any variant with a nucleotide G-350 mutation compared with HIV-negative women [58·3 % vs 21·1 %; adjusted odds ratio (AOR)=6·28, 95 % confidence interval (CI)=1·19–46·54]. Models also revealed a trend towards increased prevalence of Asian–American lineage in HIV-positive women compared with HIV-negative women (25·0 % vs 6·0 %; AOR=6·35, 95 % CI=0·77–84·97). No association was observed between any variant and cytology or CD4 cell counts or HIV-1 viral loads. These observations reflect a difference in the distribution of HPV-16 variants among HIV-positive and -negative women, indicating that HIV-positive status may lead to increased prevalence of a subset of variants.

Human papillomavirus, cytomegalovirus, and adeno-associated virus infections in pregnant and nonpregnant women with cervical intraepithelial neoplasia

Two hundred eight cervical specimens from two groups of subjects, 165 nonpregnant women and 53 pregnant women with cervical intraepithelial neoplasia (CIN) of grades I to III, were positive by PCR analyses for human papillomaviruses (HPVs), adeno-associated virus type 2 (AAV 2), and human cytomegalovirus (HCMV) in 67, 6, and 4.1% of the cases, respectively. The presence of AAV 2 infection was more frequently associated with pregnancy (17 versus 2.4%) and HPV-positive cervices (odds ratio = 6.358) than HCMV was. Increased HPV infection was strongly associated (P < 0.001) with a higher CIN grade, but there is no evidence that AAV 2 and HCMV infections have any impact on CIN development.

The Epidemiology of Cervical Cancer

Cervical cancer is one of the most common neoplastic diseases affecting women, with a combined worldwide incidence of almost half a million new cases annually, second only to breast cancer. Basic and epidemiologic research conducted during the past 15-20 years have provided overwhelming evidence for an etiologic role for infection with certain types of sexually-transmitted human papillomavirus (HPV) as the primary cause of cervical cancer. The relative risks of cervical cancer following HPV infection as ascertained in case-control and cohort studies are among the highest in cancer epidemiology. The available evidence indicates that the HPV-cervical cancer association satisfies all relevant causal criteria for public health action. Other cervical cancer risk factors, such as smoking, parity, use of oral contraceptives, diet, other infections, and host susceptibility traits must be understood in the context of mediation of acquisition of HPV infection or in influencing events of the natural history of cervical neoplasia that occur following the establishment of a persistent HPV infection. Virtually all cervical carcinoma specimens contain HPV DNA, which suggests that HPV infection is a necessary cause of cervical neoplasia. This is the first instance in which a necessary cause has been demonstrated in cancer epidemiology--a realization that has obvious implications for primary and secondary prevention of this neoplastic disease.

Human papillomavirus and cervical cancer: not just a sexually transmitted disease

The human papillomavirus (HPV) is the cause of virtually all cancers of the cervix, the fourth most common cancer in women in the United States. HPV is sexually transmitted, and the lifetime risk of contracting the virus is estimated to be 75%-90%. New methods of detecting HPV infection and cellular changes (dysplasia) caused by HPV can greatly reduce the mortality associated with this virus. More than 100 types of HPV exist and may be classified as low-, intermediate-, or high-risk in terms of causing cancer. The virus can cause genital warts, subclinical dysplasia, and cancer. Nurses play an important role in educating patients regarding HPV and preventive measures as well as in screening and treatment. Most women diagnosed with HPV need emotional support and factual information provided in a supportive, nonjudgmental manner. Nurses can meet this challenge and make a difference in reducing the incidence and mortality of cervical cancer.