Human papillomavirus infection, cervical dysplasia and invasive cervical cancer in Honduras: a case-control study

The contribution of Latin American research to HPV epidemiology and natural history knowledge

Our aim was to review the major contributions of studies conducted in different Latin American (LA) countries to the field of human papillomavirus (HPV) epidemiology, natural history, risk of disease, and prevention strategies, mainly in the uterine cervix. Although cytological screening is established in several countries in LA, incidence and mortality rates from cervical cancer (CC) are still extremely high. Finally, data from large cohort studies conducted in LA countries provided seminal data to propose primary and secondary prevention modalities: the HPV vaccine has been introduced in the national immunization programs of several LA countries and multiple screening experiences using HPV testing are under evaluation in the region.

Comparing human papillomavirus prevalences in women with normal cytology or invasive cervical cancer to rank genotypes according to their oncogenic potential: a meta-analysis of observational studies

BACKGROUND

Mucosal human papillomavirus (HPV) infection is a necessary cause of cervical cancer. Vaccine and non-vaccine genotype prevalences may change after vaccine introduction. Therefore, it appears essential to rank HPV genotypes according to their oncogenic potential for invasive cervical cancer, independently of their respective prevalences.

METHODS

We performed meta-analyses of published observational studies and estimated pooled odds ratios with random-effects models for 32 HPV genotypes, using HPV-16 as the reference.

RESULTS

Twenty-seven studies yielded 9,252 HPV-infected women: 2,902 diagnosed with invasive cervical cancer and 6,350 with normal cytology. Expressed as (odds ratio [95% confidence interval]), HPV-18 (0.63 [0.51, 0.78]) ranked closest to HPV-16, while other genotypes showed continuously decreasing relative oncogenic potentials: HPV-45 (0.35 [0.22, 0.55]), HPV-69 (0.28 [0.09, 0.92]), HPV-58 (0.24 [0.15, 0.38]), HPV-31 (0.22 [0.14, 0.35]), HPV-33 (0.22 [0.12, 0.38]), HPV-34 (0.21 [0.06, 0.80]), HPV-67 (0.21 [0.06, 0.67]), HPV-39 (0.17 [0.09, 0.30]), HPV-59 (0.17 [0.09, 0.31]), HPV-73 (0.16 [0.06, 0.41]), and HPV-52 (0.16 [0.11, 0.23]).

CONCLUSIONS

Our results support the markedly higher oncogenic potentials of HPV-16 and -18, followed by HPV-31, -33, -39, -45, -52, -58 and -59, and highlight the need for further investigation of HPV-34, -67, -69 and -73. Overall, these findings could have important implications for the prevention of cervical cancer.

Type-specific HPV prevalence in cervical cancer and high-grade lesions in Latin America and the Caribbean: systematic review and meta-analysis

Background

Cervical cancer is a major public health problem in Latin America and the Caribbean (LA&C), showing some of the highest incidence and mortality rates worldwide. Information on HPV type distribution in high-grade cervical lesions (HSIL) and invasive cervical cancer (ICC) is crucial to predict the future impact of HPV16/18 vaccines and screening programmes, and to establish an appropriate post-vaccinal virologic surveillance. The aim was to assess the prevalence of HPV types in HSIL and ICC in studies in LA&C.

Methods and Findings

We performed a systematic review, following the MOOSE guidelines for systematic reviews of observational studies, and the PRISMA statement for reporting systematic reviews and meta-analyses. Inclusion criteria were at least ten cases of HSIL/ICC, and HPV-type elicitation. The search, without language restrictions, was performed in MEDLINE, Cochrane Library, EMBASE, LILACS from inception date to December 2009, proceedings, reference lists and consulting experts. A meta-analysis was performed using arc-sine transformations to stabilize the variance of simple proportions. Seventy-nine studies from 18 countries were identified, including 2446 cases of HSIL and 5540 of ICC. Overall, 46.5% of HSIL cases harbored HPV 16 and 8.9% HPV18; in ICC, 53.2% of cases harbored HPV 16 and13.2% HPV 18. The next five most common types, in decreasing frequency, were HPV 31, 58, 33, 45, and 52.

Study's limitations comprise the cross-sectional design of most included studies and their inherent risk of bias, the lack of representativeness, and variations in the HPV type-specific sensitivity of different PCR protocols.

Conclusions

This study is the broadest summary of HPV type distribution in HSIL and ICC in LA&C to date. These data are essential for local decision makers regarding HPV screening and vaccination policies. Continued HPV surveillance would be useful, to assess the potential for changing type-specific HPV prevalence in the post-vaccination era in Latin America.

HPV types, HIV and invasive cervical carcinoma risk in Kampala, Uganda: a case-control study

Background

While the association of human papillomavirus (HPV) with cervical cancer is well established, the influence of HIV on the risk of this disease in sub-Saharan Africa remains unclear. To assess the risk of invasive cervical carcinoma (ICC) associated with HIV and HPV types, a hospital-based case-control study was performed between September 2004 and December 2006 in Kampala, Uganda. Incident cases of histologically-confirmed ICC (N=316) and control women (N=314), who were visitors or care-takers of ICC cases in the hospital, were recruited. Blood samples were obtained for HIV serology and CD4 count, as well as cervical samples for HPV testing. HPV DNA detection and genotyping was performed using the SPF₁₀/DEIA/LiPA₂₅ technique which detects all mucosal HPV types by DEIA and identifies 25 HPV genotypes by LiPA version 1. Samples that tested positive but could not be genotyped were designated HPVX. Odds ratios (OR) and 95% confidence intervals (CI) were calculated by logistic regression, adjusting for possible confounding factors.

Results

For both squamous cell carcinoma (SCC) and adenocarcinoma of the cervix, statistically significantly increased ORs were found among women infected with HPV, in particular single HPV infections, infections with HPV16-related types and high-risk HPV types, in particular HPV16, 18 and 45. For other HPV types the ORs for both SCC and adenocarcinoma were not statistically significantly elevated. HIV infection and CD4 count were not associated with SCC or adenocarcinoma risk in our study population. Among women infected with high-risk HPV types, no association between HIV and SCC emerged. However, an inverse association with adenocarcinoma was observed, while decrease in CD4 count was not associated with ICC risk.

Conclusions

The ORs for SCC and adenocarcinoma were increased in women infected with HPV, in particular single HPV infections, infections with HPV16- and 18-related types, and high-risk HPV types, specifically HPV16, 18 and 45. HIV infection and CD4 count were not associated with SCC or adenocarcinoma risk, but among women infected with high-risk HPV types there was an inverse association between HIV infection and adenocarcinoma risk. These results suggest that HIV and CD4 count may have no role in the progression of cervical cancer.

Human papillomavirus infection in Honduran women with cervical intraepithelial neoplasia or cervical cancer

OBJECTIVES

The aims of this study were to investigate human papillomavirus (HPV) genotypes in women with cervical intraepithelial lesions and cervical cancer (CC) in Honduras and to identify epidemiological cofactors that contribute to the development of CC.

METHODS

Among the 289 patients analyzed, 139 had low-grade squamous intraepithelial lesion (LSIL), 60 had high-grade squamous intraepithelial lesion (HSIL), and 90 had CC.

RESULTS

The HPV DNA was detected in 113 women (81%) with LSIL, in 58 women (97%) with HSIL, and in 84 women (93%) with CC. Twenty-five HPV genotypes were found. Human papillomavirus type 16 was detected in 41% of women with CC, in 35% of women with HSIL, and in 24% of women with LSIL. Human papillomavirus type 18 was found in 9% of women with CC, in 4% of women with HSIL, and 5% of women with LSIL.

CONCLUSION

Therefore, implementation of the prophylactic vaccines against HPV genotypes 16 and 18 has the potential of preventing at least a quarter of LSIL, one third of HSIL, and about half of CC cases in Honduras.

Detection of HPV types and neutralizing antibodies in women with genital warts in Tianjin City, China

The serum samples and corresponding cervical swabs were collected from 50 women with genital warts from Tianjin city, China. The neutralizing antibodies against HPV-16, -18, -58, -45, -6 and -11 in serum samples were tested by using pseudovirus-based neutralization assays and HPV DNAs in cervical swabs were also tested by using a typing kit that can detect 21 types of HPV. The results revealed that 36% (18/50) of sera were positive for type-specific neutralizing antibodies with a titer range of 160-2560, of which 22%(11/50), 12%(6/50), 10%(5/50), 4%(2/50), 4%(2/50) and 2%(1/50) were against HPVs -6, -16, -18, -58, -45 and -11, respectively. Additionally, 60% (30/50) of samples were HPV DNA-positive, in which the most common types detected were HPV-68(18%), HPV-16(14%), HPV-58(12%), HPV-33(8%) and HPV-6, HPV-11, HPV-18 and HPV-52 (6% each). The concordance between HPV DNA and corresponding neutralizing antibodies was 56% (28/50) with a significant difference (P<0.05). The full-length sequences of five HPV types (HPV -42, -52, -53, -58 and -68) were determined and exhibited 98%-100% identities with their reported genomes. The present data may have utility for investigating the natural history of HPV infection and promote the development of HPV vaccines.

Human papillomavirus infection in Honduran women with normal cytology

Objective

This study was aimed at estimating type-specific HPV prevalence and its cofactors among Honduran women with normal cytology in order to provide valuable information to health policymakers about the epidemiology of this important sexually transmitted infection.

Methods

A total of 591 women with normal cytology from Tegucigalpa, Honduras were interviewed and tested for HPV using the SPF10 LiPA25. A structured epidemiological questionnaire was administered to each woman.

Results

The overall HPV prevalence was 51%. Twenty-three types of HPV were detected; HPV 16, 51, 31, 18, and 11 were the most common. The highest prevalence of cancer associated HPV types (15.0%) was found in the women less than 35 years. Besides the association with age, the main independent predictors of HPV infection were the lifetime number of sexual partners and having a low socioeconomic status and less than 5 previous Pap smears.

Conclusions

In the population studied, there was a broad diversity of HPV infections, with high-risk types being the most common types detected. The establishment of a well-characterized population with regard to the community prevalence of type-specific HPV infection will provide a valuable baseline for monitoring population effectiveness of an HPV vaccine.

Detection of HPV types and neutralizing antibodies in Gansu province, China

A total of 82 samples from patients with cervical cancer (Group 1) and 50 samples from patients with other genital diseases (Group 2) were collected in Gansu, China. All 132 samples were tested for HPV DNA with a typing kit that can detect 21 types of HPV, and also tested for neutralizing antibodies against HPV-16, -18, -58, -45, -6, and -11 using pseudovirus-based neutralization assays. The results revealed that 28% (23/82) of sera in Group 1 were positive for type-specific neutralizing antibodies with a titer range of 160-640, of which 23.2% (19/82), 2.4% (2/82), 2.4% (2/82), 1.2% (1/82), and 1.2% (1/82) were against HPV-16, -58, -6, -18, and -45, respectively. Only one serum (2%) in Group 2 was positive for neutralizing antibodies, which were against HPV-6 with a titer of 2,560. Overall, 85.4% (70/82) of samples in Group 1 were HPV DNA-positive, compared with 28% (14/50) of samples in Group 2. The seven most common types detected in Group 1 were HPV-16 (80%), HPV-52 (7.1%), HPV-66 and HPV-11 (5.7% each), and HPV-58, HPV-18, and HPV-33 (4.3% each), while the four most common types in Group 2 were HPV-16 (12%), HPV-52 and HPV-11 (6% each), and HPV-68 (4%). The concordance between HPV DNA and corresponding neutralizing antibodies was 32.9% (27/82) with a significant difference (P < 0.005). More specifically, the concordance was 42.7% (35/82) for HPV-16 in Group 1. The full-length sequences of six HPV types (HPV-16, -58, -33, -59, -11, and -68) were determined and showed 99% identities with their reported genomes.

Human papillomavirus profile of women in Belize City, Belize: correlation with cervical cytopathologic findings

Cervical carcinoma is the most common cancer among Belizean women; however, data regarding the frequency of human papillomavirus (HPV) genotypes and their association with cervical cancer are nonexistent. We therefore included HPV genotyping as part of a week-long cervical cancer screening campaign conducted in Belize City in 2007. Conventional Papanicolaou smears with Hybrid Capture (HC) 2 HPV testing were performed on 463 women. All HC2-positive samples were genotyped using a developmental GP5+/GP6+ polymerase chain reaction-coupled Luminex assay for 2 low-risk and 18 high-risk HPV types. The prevalence of high-risk HPV was 15.6% in the total population, 10.1% in those with normal cytologic findings, and 93.3% in women with a high-grade squamous intraepithelial lesion. Of patients with HPV infections, 35% had multiple types (5.4% of the total group). Of all women and of women with normal cytologic findings, 5.2% and 2.8%, respectively, had HPV16 or 18. For all women, HPV16, 18, 56, and 52 were present in decreasing order of frequency. HPV11 was present in only one patient, and none had HPV6. HPV16 was found in 47% of high-grade squamous epithelial lesions; however, no case of HSIL had HPV18 or 45. HPV35 and HPV58 were the next most common types in high-grade squamous intraepithelial lesion, each occurring in 20% of cases of high-grade squamous intraepithelial lesion, followed by HPV31 in 13.3%. Although women younger than 25 years old were underrepresented, these data suggest that the HPV profile of this cohort of Belizean women differs somewhat from that in the region. In addition, these data are of importance with regard to the development of HPV vaccines that will be used in less developed countries, where care should be taken not to implement vaccination at the cost of basic screening and diagnostic services.

Age-specific prevalence of infection with human papillomavirus in females: a global review

PURPOSE

Global data on age-specific prevalence of human papillomavirus (HPV) infection overall, and for high-risk HPV types 16 and 18, are essential for the future implementation of HPV prophylactic vaccines for cervical cancer prevention.

METHODS

A systematic review of peer-reviewed publications was conducted to summarize worldwide data on genital HPV-DNA prevalence in women. Studies with clear descriptions of polymerase chain reaction or hybrid capture detection assays were included.

RESULTS

A total of 346,160 women were included in 375 studies. Of 134 studies with age-stratified HPV prevalence data (116 low sexual risk populations, 18 high sexual risk populations), over 50% were from Europe and the Middle East (38%) and North America (19%), with smaller proportions from Asia and Australia (21%), Central and South America (11%), and Africa (10%). Across all geographical regions, data on HPV prevalence were generally limited to women over 18 years of age. Consistently across studies, HPV infection prevalence decreased with increasing age from a peak prevalence in younger women (< or =25 years of age). In middle-aged women (35-50 years), maximum HPV prevalence differed across geographical regions: Africa (approximately 20%), Asia/Australia (approximately 15%), Central and South America (approximately 20%), North America (approximately 20%), Southern Europe/Middle East (approximately 15%), and Northern Europe (approximately 15%). Inconsistent trends in HPV prevalence by age were noted in older women, with a decrease or plateau of HPV prevalence in older ages in most studies, whereas others showed an increase of HPV prevalence in older ages. Similar trends of HPV 16 and/or 18 prevalence by age were noted among 12 populations with available data.

DISCUSSION

Genital HPV infection in women is predominantly acquired in adolescence, and peak prevalence in middle-aged women appears to differ across geographical regions. Worldwide variations in HPV prevalence across age appear to largely reflect differences in sexual behavior across geographical regions. Further studies of HPV prevalence in adolescents are needed for all geographic regions.

Effect of thiolated polymers to textural and mucoadhesive properties of vaginal gel formulations prepared with polycarbophil and chitosan

The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 +/- 4.16 and 41.17 +/- 2.34 micromol of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test. The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during the 3 month stability analysis under controlled room temperature and accelerated conditions.

Human papillomavirus (HPV) infection and intraepithelial neoplasia and invasive cancer of the uterine cervix: a case-control study in Zaragoza, Spain

Introduction

The raw incidence of cancer of the uterine cervix is Spain is 7,8 per 100.000 inhabitants (adjusted incidence is 5.6). The incidence of this tumor is still low, but a steady increase has been seen, probably related to increasing risk factors.

Aim

To determine the frequency of infection by different types of human papillomavirus (HPV) in Papanicolau smears from women with and without cancer of the uterine cervix in Spain.

Patients and methods

A case-control study was performed in women with and without cervical cancer from Zaragoza, Spain. Pap smears from 600 cases (540 women with cervical intraepithelial neoplasms (CIN) and 60 with invasive cancer) and 1200 controls (women without those lesions) were tested by polymerase chain reaction (PCR) and typed by oligonucleotide microarray-based detection.

Results

HPV was detected in 93.3% of all samples with invasive cancer versus 17.5% of controls. OR for invasive cancer was 55 (95% CI 21.5–140,5). Statistically significant associations were also found for different grades of cervical dysplasia.

Conclusion

The strong association found between HPV infection, specifically types 16 and 18 and cancer of the uterine cervix in Zaragoza, Spain, stresses the importance of ongoing efforts to institute a vaccine program with recently approved HPV vaccines in order to prevent cervical cancer in this population.

Pitfalls in the epidemiologic classification of human papillomavirus types associated with cervical cancer using polymerase chain reaction: driver and passenger

Cervical cancer is a common malignancy in women worldwide, and it has now been established that the human papillomavirus (HPV) is both necessary and causal for these lesions. HPV itself is both ubiquitous and markedly heterogeneous but can nevertheless be classified as either a high-risk type or a low-risk type based upon its frequency of detection in cervical cancer. Given that the association between HPV and cervical cancer is causal, the classification of this virus has been strengthened by large-scale epidemiologic studies and is widely accepted across many disciplines. It is evident, however, that cervical cancer is frequently associated with multiple HPV types. Therefore, it is crucial to distinguish causal types of HPV (drivers) from noncausal types (passengers) in cervical lesions. In this review, we highlight the current pitfalls of using polymerase chain reaction methods instead of Southern blot hybridization for detecting HPV and discuss the distinction between driver and passenger HPVs with regard to the viral type, the length of the viral genome, and the levels of viral DNA associated with cervical cancer. Finally, we newly propose three categories of HPV instead of two risk groups, based on similarities between viral genes.

The apoptotic effect of intercalating agents on HPV-negative cervical cancer C-33A cells

Cervical cancer is one of the leading causes of female cancer death worldwide with about 500,000 deaths per year. Both mitomycin C and cisplatin are alkylating agents, which bind and intercalate DNA, and thus used as anti-cancer drugs. In these studies, we focused on investigating the apoptotic effects of intercalating agents on HPV-negative cervical cancer C-33A cells. Accordingly, C-33A cells were treated with carboplatin, mitomycin C or cisplatin. Cell cycle analysis revealed that treatment with mitomycin C and cisplatin but not with carboplatin resulted in apoptosis. Both mitomycin C and cisplatin induced apoptosis in C-33A cells via caspase-8 and -3 processing in a Fas/FasL-dependent manner and also suppressed IL-18 expression, while they down-regulated IkappaB expression and up-regulated p65 expression. These results suggest that both mitomycin C and cisplatin induce apoptosis, not only via the caspase-8 and -3 dependent Fas/FasL pathway, but also via the regulation of NF-kappaB activity and IL-18 expression in HPV-negative cervical cancer C-33A cells.

Mitomycin C induces apoptosis via Fas/FasL dependent pathway and suppression of IL-18 in cervical carcinoma cells

Mitomycin C (MMC) is used fairly widely as an anticancer drug, as it possesses mechanisms of action which are preferable to other chemotherapeutic compounds, including cisplatin, docetaxel, and lovastatin. In the previous study, we established the RSV-luc promoter analysis system, which is used to screen drugs against cervical carcinomas caused by HPV infection. We then demonstrated the repression of HPV E6-activated RSV promoter activity by anticancer agents such as carboplatin (CA), cisplatin (CIS), and MMC. In these studies, we focused on the investigation of apoptotic mechanisms in MMC-treated cervical carcinoma cell lines, most notably SiHa/pRSV-luc (KCTC 0427BP) and SiHa. DNA fragmentation assays and TUNEL staining revealed that MMC and CIS, but not CA, resulted in apoptosis. MMC treatment induced a reduction in the expressions of the E6 oncogene and IL-18, in a p53-independent manner. MMC also increased FasL expression and induced the processing of caspases-8 and -3. Our results indicated that MMC induced apoptosis in SiHa/pRSV-luc and SiHa cells via caspase-8 and -3 processing, in a Fas/FasL-dependent manner. MMC also suppressed the expression of IL-18 in the same cells. MMC also down-regulated IkappaB expression, and up-regulated p65 expression. These results suggest that MMC induces apoptosis, not only through caspase-8 and -3 dependent Fas/FasL pathway, but also via the regulation of NF-kappaB activity and IL-18 expression.

Genetic polymorphisms of FAS and FASL (CD95/CD95L) genes in cervical carcinogenesis: An analysis of haplotype and gene-gene interaction

OBJECTIVE

Whereas human papillomavirus (HPV) infection is necessary but not sufficient for cervical carcinogenesis, host genetic variations may confer individual susceptibility. Resistance to apoptosis is a hallmark of cancer in which FAS/FAS ligand signaling plays an important role. The present study examines the hypothesis that genetic polymorphisms in FAS and FAS ligand genes, alone or in combination, are associated with cervical carcinogenesis.

METHODS

The genotypes of FAS -670A/G, FAS -1377G/A, and FASL -844C/T were assessed in 143 patients with high-grade squamous intraepithelial lesions (HSIL), 175 patients with invasive squamous cell carcinomas (SCC), and in age-matched controls by real-time PCR with allele-specific TaqMan probes. The status of cervical high-risk HPV infection was determined and adjusted to test the independence of genotype in the risk assessment.

RESULTS

The A-allele and AA-genotype frequencies of FASA -670G were significantly higher in HSIL/SCC than in controls (60% vs. 54%, P = 0.04, OR 1.26 [95% CI 1.01-1.57]; 38.0% vs. 28.6%, P = 0.02, OR 1.70 [95% CI 1.07-2.70]). No association between FAS -1377 or FASL -844 polymorphisms and HSIL/SCC could be identified. The FAS -1377A/-670A haplotype conferred a higher risk for HSIL/SCC (OR 3.05, 95% CI 1.28-7.30) than FAS -670A alone (OR 1.26, 95% CI 1.28-7.30). The interaction between FAS -670AA and FASL -844CC genotypes was associated with a risk of HSIL/SCC (OR 2.13, 95% CI 1.06-4.29) higher than that of the FAS -670AA genotype alone (OR 1.70, 95% CI 1.07-2.70).

CONCLUSIONS

The FAS -1377A/-670A haplotype in combination with FASL -844C is associated with cervical carcinogenesis.

Human papillomavirus and abnormal Pap test results in Vietnamese-American women: a pilot case-control study

OBJECTIVE

To evaluate the relationship between abnormal Pap test results and human papillomavirus (HPV) in Vietnamese-American women, who have the highest cervical cancer incidence in the United States.

MATERIALS AND METHODS

In 2001, we obtained specimens from 117 Vietnamese women, 24 with abnormal Pap test results including atypical squamous cells of undetermined significance (cases) and 93 with normal Pap test results (controls), as classified by the 1991 Bethesda System. We used L1 consensus primers MY09/MY11 to perform HPV polymerase chain reaction analysis and type-specific probes to perform genotyping.

RESULTS

Thirteen cases (54%) and 6 controls (6%) were HPV positive (p < .001). Ten of 24 cases (42%) and 0 controls (0%) had high-risk HPV types (16, 18, 45, 53, 56, or 66; p < .001). High-risk HPV types were significantly associated with increasing severity of Pap test results.

CONCLUSIONS

Compared with those with normal Pap test results, Vietnamese-American women with abnormal Pap test results were more likely to have high-risk HPV types. Higher cervical cancer incidence among these women is likely the result of less frequent Pap screening rates and not different biology.

Cervical cancer among Hmong women in California, 1988 to 2000

BACKGROUND

The Hmong immigrated to the United States from Laos after the Vietnam conflict ended. Hmong encounter numerous readjustment issues, including health care. Traditional Hmong health beliefs and practices encompass more spiritual than biological etiologies. Hmong usually seek the first course of treatment from traditional healers, as they had in Laos. This practice delays early diagnosis and treatment of disease because biomedicine is used only as a last resort. This study examined cervical cancer incidence, mortality, and other tumor characteristics in the Hmong female population of California between 1988 and 2000.

METHODS

Data from the California Cancer Registry were used to calculate annual average incidence, mortality, and age-specific rates for Hmong women diagnosed with cervical cancer. The population at risk was estimated with linear interpolation using data from the 1990 and 2000 censuses.

RESULTS

Hmong women experienced incidence and mortality rates three and four times higher than Asian/Pacific Islander and non-Hispanic white women, respectively. Fifty-one percent of Hmong women chose no treatment, compared to 5.8% for Asian/Pacific Islander women and 4.8% for non-Hispanic white women. Hmong women aged >/= 40 years carried an unequal burden of cervical cancer. They were more likely to be diagnosed with cervical cancer at later stages and poorer histologic grades, and had a lower survival rate than younger Hmong females.

CONCLUSIONS

Cervical cancer is clearly a public health issue that threatens the health and well-being of Hmong women. Culturally sensitive screening and prevention programs need to be developed to target older Hmong women using bilingual and bicultural Hmong women health educators using verbal communication.

Human papillomavirus genomes in squamous cell carcinomas of the uterine cervix

The association between invasive cervical carcinoma and human papillomavirus (HPV) has now been established beyond doubt, but this is not necessarily a direct-and-effect association. To assess the causality of HPV, we analyzed HPV genomes in squamous cell carcinomas (SCCs) [corrected] of the uterine cervix by both blot hybridization and PCR. Genital HPV sequences were found in 231 (79%) of 294 SCCs by blot hybridization with more than five copies of entire HPV genomes identified in some cases including HPV 16 (92 cases), HPV 58 (32 cases), and HPV 52 (24 cases). By PCR-direct sequence analysis in 250 of 294 SCCs, genital HPV sequences were found in 240 samples (96%). The partial L1 sequences of HPV 16 were identified in 123 cases, and those of HPVs 18 and 31 were found in 24 and 20 cases, respectively. In addition, multiple HPV types were identified in 29 (12%) of 250 SCCs, and the HPV copy number, detected by PCR only, was less than 0.05. Marked discrepancies were therefore evident between the two analytical techniques. In this report, we discuss the causality of HPV for SCC with regard to the length of the viral genome, the amount of viral DNA, and multiple HPVs in single SCCs.

Distribution of human papillomavirus in a family planning population in nairobi, kenya

BACKGROUND

In sub-Saharan Africa, cervical cancer is the leading cancer among women. The causative role of different human papillomavirus (HPV) types in cervical cancer is established, but the distribution of HPV types within this region is largely unknown.

GOAL

The goal was to study the distribution of HPV among family planning clinic attendees in Nairobi, Kenya.

STUDY DESIGN

This was a cross-sectional study of persons attending a family planning center in Nairobi, Kenya.

RESULTS

HPV data of 429 women were analyzed; 7.0% had low-grade intraepithelial lesions, 6.8% had high-grade intraepithelial lesions, and 0.23% had invasive cancer. One hundred ninety samples (44.3%) were HPV-positive (28.4% were positive for multiple types). The most common HPV types were HPV 52 (17.9% of positive samples), HPV 16 (14.7%), HPV 35 (11.6%), and HPV 66 (9.0%). The risk of high-grade squamous intraepithelial lesions (HSIL) was 88.5 times higher (95% CI, 8.5-1.4 x 10 ) in HPV 16-positive women than in HPV-negative women. Relative risks were 54.3 (95% CI, 4.0-1.4 x 10 ) for HPV 35, 49.2 (95% CI, 3.6-9.5 x 10 ) for HPV 52, and 21.7 (95% CI, 0.0-1.9 x 10 ) for HPV 18. The prevalence of HSIL was not increased in association with HIV-positivity, yet HIV-1 was significantly associated with high-risk HPV types ( P< 0.00001).

CONCLUSION

The pattern of HPV distribution in this population was different from that in other regions in the world, which has important consequences for HPV vaccine development.

Costs and benefits of different strategies to screen for cervical cancer in less-developed countries

BACKGROUND

About 80% of cervical cancers occur in less-developed countries. This disproportionate burden of cervical cancer in such countries is due mainly to the lack of well-organized screening programs. Several cervical cancer screening strategies have been proposed as more cost-effective than cytology screening. We compared the costs and benefits of different strategies and their effectiveness in saving lives in a less-developed country.

METHODS

We used a population-based simulation model to evaluate the incremental societal costs and benefits in Thailand of seven screening techniques, including visual inspection of the cervix after applying acetic acid (VIA), human papillomavirus (HPV) testing, Pap smear, and combinations of screening tests, and examined the discounted costs per year of life saved (LYS).

RESULTS

Compared with no (i.e., not well-organized) screening, all strategies saved lives, at costs ranging from 121 US dollars to 6720 US dollars per LYS, and reduced mortality, by up to 58%. Comparing each strategy with the next least expensive alternative, VIA performed at 5-year intervals in women of ages 35-55 with immediate treatment if abnormalities are found was the least expensive option and saved the greatest number of lives, with a cost of 517 US dollars per LYS. HPV screening resulted in similar costs and benefits, if the test cost is 5 US dollars and if 90% of women undergo follow-up after an abnormal screen. Cytology (Pap smear) was a reasonable alternative if sensitivity exceeds 80% and if 90% of women undergo follow-up. Compared with no screening, use of a combination of Pap smear and HPV testing at 5-year intervals in women of ages 20-70 could achieve greater than 90% reduction in cervical cancer mortality at a cost of 1683 US dollars per LYS, and VIA could achieve 83% reduction at 524 US dollars per LYS.

CONCLUSIONS

Well-organized screening programs can reduce cervical cancer mortality in less-developed countries at low costs. These cost-effectiveness data can enhance decision-making about optimal policies for a given setting.

Burning wood in the kitchen increases the risk of cervical neoplasia in HPV-infected women in Honduras

There is suggestive evidence that the use of wood for cooking increases the risk of invasive cervical cancer. We investigated this association in women with cervical neoplasia in Honduras. Women aged 20-64 years with cervical intraepithelial neoplasia (CIN) grade I (n = 44), CIN II (n = 36) or CIN III (n = 45) were recruited from screening programs in Tegucigalpa City and each was matched by age and clinic to 2 controls (241 total) without cervical abnormalities. The clinics selected women of low socioeconomic status. Cervical scrapes were tested for the presence of human papillomavirus (HPV) DNA using a general primer set directed against the L1 open reading frame, and HPV genotyping was performed. Odds ratios (ORs) were computed through conditional logistic regression; p-values were from tests for linear trend of risk with increasing exposure. HPV DNA was detected in 48% of women with CIN I, 67% with CIN II and 89% with CIN III. The ORs were 1.5, 2.5 and 38.3 respectively. At univariate analysis, age at first intercourse was consistently lower among cases than controls. Risk was reduced by 50% or more in all 3 CIN classes when initiation of sexual activity at age 20 years or older was compared with initiation before age 16 years (p = 0.013 for CIN I). No effect was observed for smoking, oral contraceptives or previous cytologic screening. Effects for number of sexual partners, parity, age at first pregnancy and education were in the expected directions but never persisted after adjustment for HPV. Chronic exposure to wood smoke significantly increased the risk of CIN III (p = 0.022). However, women who said "No" when asked if they ever used wood in the kitchen had a higher risk than those with low or intermediate exposure. This was taken as evidence that the initial screening question had either been misunderstood or that answers were biased. Restricting the analysis to women who reported exposure yielded positive associations in all CIN classes with for CIN III ORs of 2.3 for 25-34 and 9.5 for 35+ years compared with women who had 1-14 years of exposure (p = 0.017). A multivariate analysis of the complete dataset (n = 366) allowed for separate ORs for HPV in each CIN class. Inclusion of age at first intercourse significantly improved this model (p = 0.021). Adding exposure to wood smoke further improved the model only if an interaction between woodsmoke and HPV was allowed for. If, as the data suggest, it was assumed that wood smoke had its effect among HPV-positives only, there was a significant linear dose-response relationship between exposure to woodsmoke and risk of CIN (p = 0.026). This association was independent of other risk factors including education, parity and number of sexual partners. ORs in the final model were 0.37 for age at first intercourse 20 years or higher and 5.69 for more than 35 years of exposure to wood burning in the kitchen. The present study suggests that the use of wood for cooking is a risk factor for cervical neoplasia that deserves further study, given its high prevalence in developing countries.

Relationships between 80 human papillomavirus genotypes and different grades of cervical intraepithelial neoplasia: association and causality

To clarify the causal relationship between human papillomavirus (HPV) and cervical intraepithelial neoplasia (CIN), we analyzed 386 unfixed biopsy specimens by blot hybridization at Tm -40 degrees C, targeting 38 skin and 42 genital HPVs. By the recognition of PstI, BanI, and MspI cleavage patterns, single genital, but no skin's HPVs were identified with more than 10 copies per cell in 354 CIN (88 CIN I, 94 CIN II, and 172 CIN III). HPVs 40, 42, 43, 54, 62, or 71 was found in 10 CIN I, while HPVs 18, 30, 39, 51, 56, 59, 66, 68, 69, or 82 was found in 35 CIN I, 20 CIN II, or 8 CIN III. On the other hand, HPVs 16, 31, 33, 35, 52, 58, or 67 was identified in 43 CIN I, 74 CIN II, or 164 CIN III. The results are strongly indicative that most genital HPVs have potency to induce CIN I; however, HPV 16 and its closely related types are able to efficiently induce CIN III. We discuss the definition of causal HPV for CIN with regard to viral prevalence and viral load.

Co-factors related to the causal relationship between human papillomavirus and invasive cervical cancer in Honduras

BACKGROUND

A case-control study was conducted in Honduras to identify co-factors in the carcinogenic pathway by which human papillomavirus (HPV) causes invasive cervical cancer.

METHODS

Ninety-nine cases aged 23-65 (median 47) years participated. Two controls were matched to each case by age and clinic where they first presented for cytological screening; controls had no cervical abnormalities. Information on risk factors was obtained by personal interviews in the clinics regarding sociodemographic, reproductive and behavioral characteristics. Human papillomavirus was detected in cervical scrapes by general primer-mediated polymerase chain reaction (PCR) followed by sequence analysis to identify the different types present.

RESULTS

All cases had squamous cell tumours and most were FIGO (International Federation of Gynecologists and Obstetricians) class II or higher; HPV was strongly associated with cervical cancer (odds ratio [OR] = 7.66, 95% CI : 3.88-15.1). Among HPV-positive women, dose-response relationships were observed for education, age at first intercourse and exposure to wood smoke that persisted after adjustment for previous screening. Among HPV-negative women, the number of sexual partners and parity were associated with cervical cancer. The protective effect of previous cytological screening operated independently of HPV.

CONCLUSIONS

Our findings speak for the powerful role that both primary and secondary education plays in fostering a lifestyle that reduces the risk of invasive cervical cancer. The data suggest that important elements of such a lifestyle include later age at first sexual intercourse, a limited number of pregnancies, greater likelihood of undergoing cytological screening and reduced exposure to carcinogens in the household environment.