Plasma cytokine levels and human papillomavirus infection at the cervix in rural Nigerian women

INTRODUCTION

We conducted a study to test the hypothesis that systemic dysregulation of Th1/Th2 cytokine levels was associated with detection of carcinogenic or overall human papillomavirus (HPV) at the cervix among 964 women residing in a rural village in Nigeria.

METHODS

Levels in plasma were measured for 19 cytokines, including Th1-like cytokines IL-2, IL-12 (p40), TNF-a, IFN-g; Th2-like cytokines IL-4, IL-5, IL-6, IL-10, IL-13; innate/inflammation cytokines IL-1a, IL-1b, IL-8, eotaxin, MCP-1, MIP-1a, and IL-7; and cell development cytokines G-CSF, VEGF, and IL-17. Analysis was restricted to 5 cytokines, TNF-α (Th1), IL-8 (Th2), eotaxin and MCP-1 (innate/inflammation), and G-CSF (cell development), whose levels were detected in 80% or more of the samples measured as well as had a coefficient of variation of <30%.

RESULTS

Strong correlations were noted between levels of eotaxin and TNF-α (r=0.75), IL-8 and MCP-1 (r=0.60), eotaxin and G-CSF (r=0.44), and G-CSF and IFN-γ (r=0.43). Detection of carcinogenic or non-carcinogenic HPV DNA was unrelated to cytokine levels, except for levels of eotaxin and TNF-α, which were inversely correlated, albeit weakly, with detection of any carcinogenic HPV (P=0.048 and P=0.067, respectively). In analyses stratified by age group, levels of eotaxin were inversely correlated with detection of any HPV DNA (P=0.026) and carcinogenic HPV (P=0.042) in older, but not younger, women.

CONCLUSIONS

Our results do not support the hypothesis of association between systemic cytokine dysregulation and detection of HPV at the cervix in Nigerian women, but subgroup analyses raise questions about inverse associations between eotaxin and TNF-α in older women.

Novel genital alphapapillomaviruses in baboons (Papio hamadryas anubis) with cervical dysplasia

Genital Alphapapillomavirus (αPV) infections are one of the most common sexually transmitted human infections worldwide. Women infected with the highly oncogenic genital human papillomavirus (HPV) types 16 and 18 are at high risk for development of cervical cancer. Related oncogenic αPVs exist in rhesus and cynomolgus macaques. Here the authors identified 3 novel genital αPV types (PhPV1, PhPV2, PhPV3) by PCR in cervical samples from 6 of 15 (40%) wild-caught female Kenyan olive baboons (Papio hamadryas anubis). Eleven baboons had koilocytes in the cervix and vagina. Three baboons had dysplastic proliferative changes consistent with cervical squamous intraepithelial neoplasia (CIN). In 2 baboons with PCR-confirmed PhPV1, 1 had moderate (CIN2, n = 1) and 1 had low-grade (CIN1, n = 1) dysplasia. In 2 baboons with PCR-confirmed PhPV2, 1 had low-grade (CIN1, n = 1) dysplasia and the other had only koilocytes. Two baboons with PCR-confirmed PhPV3 had koilocytes only. PhPV1 and PhPV2 were closely related to oncogenic macaque and human αPVs. These findings suggest that αPV-infected baboons may be useful animal models for the pathogenesis, treatment, and prophylaxis of genital αPV neoplasia. Additionally, this discovery suggests that genital αPVs with oncogenic potential may infect a wider spectrum of non-human primate species than previously thought.

Classification and nomenclature system for human Alphapapillomavirus variants: general features, nucleotide landmarks and assignment of HPV6 and HPV11 isolates to variant lineages

BACKGROUND

Papillomaviruses constitute a family of viruses that can be classified into genera, species and types based on their viral genome heterogeneity. Currently circulating infectious human Alphapapillomaviruses (alpha-PVs) constitute a set of viral genomes that have evolved from archaic times and display features of host co-speciation. Viral variants are more recently evolved genomes that require a standardized classification and nomenclature.

OBJECTIVES

To describe a system for the classification and nomenclature of HPV viral variants and provide landmarks for the numbering of nucleotide positions.

METHODS

The complete 8 kb genomes of the alpha-9 species group and HPV6 and 11 types, collected from isolates throughout the world were obtained from published reports and GenBank. Complete genomes for each HPV type were aligned using the E1 start codon and sequence divergence was calculated by global and pairwise alignments using the MUSCLE program. Phylogenetic trees were constructed from the aligned sequences using a maximum likelihood method (RAxML).

RESULTS

Pairwise comparisons of nucleotide differences between complete genomes of each type from alpha-9 HPV isolates (HPV16, 31, 33, 35, 52, 58 and 67) revealed a trimodal distribution. Maximum heterogeneity for variants within a type varied from 0.6%-2.3%. Nucleotide differences of approximately 1.0%-10.0% and 0.5%-1.0% of the complete genomes were used to define variant lineages and sublineages, respectively. Analysis of 43 HPV6 complete genomes indicated the presence of 2 variant lineages, whereas 32 HPV11 isolates were highly similar and clustered into 2 sublineages. A table was constructed of the human alpha-PV landmark nucleotide sequences for future reference and alignments.

CONCLUSIONS

A proposed nomenclature system for viral variants and coordination of nucleotide positions will facilitate the comparison of variants across geographic regions and amongst different populations. In addition, this system will facilitate study of pathogenic, tissue tropism and functional differences amongst variant lineages of and polymorphisms within HPV variants.

Novel betapapillomavirus associated with hand and foot papillomas in a cynomolgus macaque

Betapapillomavirus is a genus of papillomaviruses (PVs) commonly found in human skin and associated with both benign and malignant skin lesions. Only 2 previous beta-PVs have been fully characterized in nonhuman species. This report describes a novel beta-PV, named Macaca fascicularis PV type 2 (MfPV2), isolated from exophytic skin papillomas on the hands and feet of a 2-year-old male cynomolgus monkey (M. fascicularis). On histology the papillomas were composed of diffusely thickened epidermis with superficial foci of cytomegaly, cytoplasmic pallor, marginalized chromatin, and rare eosinophilic intranuclear inclusion bodies. Positive immunostaining for p16 and the proliferation marker Ki67 was present multifocally within affected epidermis, most prominently within basal-type cells. Complete sequence identity (100%) was noted between PV genomes fully sequenced from hand and foot lesions. The MfPV2 genome was 7632 base pairs in length and included putative open reading frames (ORFs) for E1, E2, E4, E6, E7, L1, and L2 genes, similar to other PVs. The closest relatives to MfPV2 based on the L1 ORF sequence were all beta-PVs. These included human PV (HPV) 9, HPV115, HPV76, HPV75, and MfPV1 (60-70% pairwise identity for all), the latter of which was also isolated from hand and foot papillomas in a cynomolgus macaque. Phylogenetic analysis placed MfPV2 in a new species group (beta-6), distinct from HPVs (beta-1 to beta-5) and MfPV1 (beta-1). These findings characterize a new nonhuman beta-PV and provide additional support for the idea that tissue tropism among ancestral primate PVs developed prior to divergence of certain Old World primate lineages.

Gene expression profiles in HPV-infected head and neck cancer

Epidemiological and laboratory evidence indicate that, in addition to tobacco and alcohol, human papillomaviruses (HPV) play an important aetiological role in a subset of head and neck squamous cell carcinoma (HNSCC). To evaluate the molecular pathogenesis of HPV-infected HNSCC, we compared gene expression patterns between HPV-positive and -negative HNSCC tumours using cDNA microarrays. Tumour tissue was collected from 42 histologically confirmed HNSCC patients from an inner-city area of New York. Total DNA and RNA were extracted and purified from frozen tumour samples and gene expression levels were compared to a universal human reference RNA standard using a 27 323 cDNA microarray chip. HPV detection and genotyping were performed using an MY09/11-PCR system and RT-PCR. HPV was detected in 29% of HNSCC tumours. Most harboured only HPV16 and expressed the HPV16-E6 oncogene. HPV prevalence was highest in pharyngeal tumours (45%). Gene expression patterns that differentiated HPV-positive from negative tumours were compared by supervised classification analysis, and a multiple-gene signature was found to predict HPV16 prevalence in primary HNSCC with a false discovery rate < 0.2. Focusing on never-smokers, we further identified a distinct subset of 123 genes that were specifically dysregulated in HPV16-positive HNSCC. Overexpressed genes in HPV-positive HNSCC tumours included the retinoblastoma-binding protein (p18), replication factor-C gene, and an E2F-dimerization partner transcription factor (TFDP2) that have also been found to be overexpressed in cervical cancer. An additional subset of genes involved in viral defence and immune response, including interleukins and interferon-induced proteins, was found to be down-regulated in HPV-positive tumours, supporting a characteristic and unique transcriptional profile in HPV-induced HNSCC.

Cervical HPV DNA detection as a predictor of a recurrent SIL diagnosis among untreated women

OBJECTIVES

This study was conducted to test whether patient history of untreated cervical intraepithelial neoplasia (CIN) 1 or low-grade squamous intraepithelial lesions (LGSIL) modifies the interpretation of a positive HPV DNA result with regards to subsequent squamous intraepithelial lesions (SIL).

METHODS

Seventy-three women with recurrent SIL were compared to 105 controls who remain cytologically normal during follow up. Cervical samples collected at enrollment were assayed for HPV DNA in the subject and control groups.

RESULTS

Women with and without a history of LGSIL who tested positive for HPV DNA were at a similarly increased risk of having (recurrent) LGSIL as compared to controls. However, in women with a history of LGSIL, HPV DNA appeared to be less predictive for high-grade squamous intraepithelial lesions (HGSIL) than in women without a history of disease.

CONCLUSIONS

Past history of untreated CIN1 or LGSIL does not modify the predictive value of a positive HPV DNA test for subsequent LGSIL. The observed difference of the predictive value of a positive HPV DNA test for the risk of recurrent HSIL compared to incident HSIL should be pursued.

Determinants of human papillomavirus 16 serological conversion and persistence in a population-based cohort of 10 000 women in Costa Rica

Determinants of human papillomavirus (HPV)-16 serological conversion and persistence were assessed in a population-based cohort of 10 049 women in Guanacaste, Costa Rica. Serologic responses to HPV-16 were measured in 7986 women by VLP-based enzyme-linked immunosorbent assay at both study enrolment (1993/94) and at 5–7 years of follow-up. Seropositive women were defined as ⩾5 standard deviations above the mean optical density obtained for studied virgins at enrolment (n=573). Seroconnversion (n=409), persistence (n=675), and clearance (n=541) were defined based on enrolment and follow-up serology measurements. Age-specific distributions revealed that HPV-16 seroconversion was highest among 18- to 24-year-old women, steadily declining with age; HPV-16 seropersistence was lowest in women 65+ years. In age-adjusted multivariate logistic regression models, a 10-fold risk increase for HPV-16 seroconversion was associated with HPV-16 DNA detection at enrolment and follow-up; two-fold risk of seroconversion to HPV-16 was associated with increased numbers of lifetime and recent sexual partners and smoking status. Determinants of HPV-16 seropersistence included a 1.5-fold risk increase associated with having one sexual partner during follow-up, former oral contraceptive use, and a 3-fold risk increase associated with HPV-16 DNA detection at both enrolment and follow-up. Higher HPV-16 viral load at enrolment was associated with seroconversion, and higher antibody titres at enrolment were associated with seropersistence.

A case-control study of endogenous hormones and cervical cancer

Both parity and oral contraceptive use are associated with elevated circulating levels of sex hormones, at least transiently, and with increased risk of cervical cancer in human papillomavirus (HPV)-infected women. We directly evaluated whether elevations in the physiologic levels of these hormones predispose to the development of cervical neoplasia. We identified 67 premenopausal and 43 postmenopausal women with cervical intraepithelial neoplasia 2, 3, or cervical cancer (>/=CIN2) diagnosed during enrollment of a population-based cohort of 10 077 women. Four controls, two chosen randomly and two chosen from women testing positive for cancer-associated HPV, were matched to each case on menopausal status, age, days since last menses (pre), or years since menopause (post). Sex hormone-binding globulin, oestradiol, oestrone, oestrone-sulphate, dehydroepiandrosterone sulphate, and progesterone were measured in enrollment plasma. There was no consistent association between the sex hormones and risk of >/=CIN2. Excluding cases with invasive disease had a minimal impact on results. Though this case-control study was based on a well-defined population, it was limited by reliance on a single measure of hormone levels taken at the time of diagnosis. Nonetheless, our results do not support the hypothesis that plasma levels of sex hormones have an important bearing on the risk of cervical neoplasia in HPV-infected women.

A population based study of herpes simplex virus 2 seroprevalence in rural Costa Rica

OBJECTIVES

To determine seroprevalence and determinants of herpes simplex virus 2 (HSV-2) seropositivity, in a random sample of a population based cohort of 10 049 women of Guanacaste, Costa Rica, using a highly sensitive and specific serological assay.

METHODS

Seroprevalence was determined by a type specific HSV-2 ELISA assay in an age stratified random sample of 1100 women. Univariate and multivariate logistic regression was used to calculate odds ratios and 95% confidence intervals for risk factors of seropositivity.

RESULTS

Overall age adjusted HSV-2 seroprevalence was 38.5% (95% CI, 37.5 to 39.5), and it was strongly associated with increasing age (p(Trend<0.0001)), both among monogamous women and women with multiple sexual partners. A greater number of lifetime sexual partners increased the risk of seropositivity, with a 28.2% (95% CI, 24.4 to 32.2) seroprevalence among monogamous women and 75% (95% CI, 65.6 to 83.0) seroprevalence for those with four or more partners (OR = 7.6 95% CI, 4.7 to 12.4 p(Trend<0.0001)). Barrier contraceptive use was negatively associated with HSV-2 seropositivity (OR 0.54, 95% CI, 0.31 to 0.94). Women with antibodies against HPV 16, 18, or 31 were 1.6 times more likely to be HSV-2 seropositive (OR 1.6, 95% CI, 1.2 to 2.1).

CONCLUSIONS

HSV-2 infection is highly endemic in Guanacaste, even among lifetime monogamous women, suggesting a role of male behaviour in the transmission of the infection. Until vaccination against HSV-2 is available, education to prevent high risk sexual behaviour and the use of condoms appear as preventive measures against HSV-2.

Seroprevalence of human papillomavirus-16, -18, -31, and -45 in a population-based cohort of 10000 women in Costa Rica

Human papillomavirus (HPV) seroprevalence and determinants of seropositivity were assessed in a 10049-woman population-based cohort in Guanacaste, Costa Rica. Serologic responses based on VLP-based ELISA were obtained from the plasma collected at study enrollment in 1993/1994 for HPV-16 (n=9949), HPV-18 (n=9928), HPV-31 (n=9932), and HPV-45 (n=3019). Seropositivity was defined as five standard deviations above the mean optical density obtained for studied virgins (n=573). HPV-16, -18, -31, and -45 seroprevalence was 15, 15, 16, and 11%, respectively. Of women DNA-positive for HPV-16, -18, -31, or -45, seropositivity was 45, 34, 51, and 28%, respectively. Peak HPV seroprevalence occurred a decade after DNA prevalence; lifetime number of sexual partners was the key determinant of seropositivity independent of DNA status and age. DNA- and sero-positive women showed the highest risk for concurrent CIN3/cancer, followed by DNA-positive, sero-negative women.

Polymorphism of the insulin gene is associated with increased prostate cancer risk

High insulin levels are linked with increased cancer risk, including prostate cancer. We examined the associations between prostate cancer with polymorphisms of the insulin gene (INS) and its neighbouring genes, tyrosine-hydroxylase and IGF-II (TH and IGF2). In this study, 126 case-control pairs matched on age, race, and countries of origin were genotyped for +1127 INS-PstI in INS, -4217 TH-PstI in TH, and +3580 IGF2-MspI in IGF2. The homozygous CC genotype of +1127 INS-PstI occurred in over 60% of the population. It was associated with an increased risk of prostate cancer in nondiabetic Blacks and Caucasians (OR=3.14, P=0.008). The CC genotype was also associated with a low Gleason score <7 (OR=2.60, P=0.022) and a late age of diagnosis (OR=2.10, P=0.046). Markers in the neighbouring genes of INS showed only null to modest associations with prostate cancer. The polymorphism of INS may play a role in the aetiology of prostate cancer. Given the high prevalence of the CC genotype and its association with late age of onset of low-grade tumours, this polymorphism may contribute to the unique characteristics of prostate cancer, namely a high prevalence of indolent cancers and the dramatic increase in incidence with age.

Human leukocyte antigen class I and II alleles and risk of cervical neoplasia: results from a population-based study in Costa Rica

To examine human leukocyte antigen (HLA) involvement in the development of all grades of cervical neoplasia, a nested case-control study of 10,077 women in Guanacaste, Costa Rica, was conducted. Participants had invasive cervical cancer, high-grade squamous intraepithelial lesions (HSILs; n=166), or low-grade squamous intraepithelial lesions (LSILs); were positive for human papillomavirus (HPV) with no evidence of cervical neoplasia (n=320); or were HPV negative with no evidence of cervical neoplasia but with a history of high-risk sexual behavior (n=173). Compared with women who were HPV negative, women with HLA-DRB1*1301 were associated with decreased risk for cancer/HSILs (odds ratio [OR], 0.4; 95% confidence interval [CI], 0.2-0.7) and for LSILs/HPV (OR, 0.6; 95% CI, 0.3-0.9). Women with both HLA-B*07 and HLA-DQB1*0302 had an 8.2-fold increased risk for cancer/HSILs (95% CI, 1.8-37.2) and a 5.3-fold increased risk for LSILs/HPV (95% CI, 1.2-23.7). These results support the hypothesis that multiple risk alleles are needed in order to increase risk for cervical neoplasia, but a single protective allele may be sufficient for protection.

The von Hippel-Lindau gene product inhibits renal cell apoptosis via Bcl-2-dependent pathways

Previous studies have reported a protective role for the von Hippel-Lindau (VHL) gene products against pro-apoptotic cellular stresses, but the mechanisms remain unclear. In this study, we examined the role of VHL in renal cells subjected to chemical hypoxia, using four VHL-negative and two VHL-positive cell lines. VHL-negative renal carcinoma cells underwent apoptosis following chemical hypoxia (short-term glucose deprivation and antimycin treatment), as evidenced by morphologic changes and internucleosomal DNA cleavage. Reintroduction of VHL expression prevented this apoptosis. VHL-negative cells displayed a significant (greater than 5-fold) activation of caspase 9 and release of cytochrome c into the cytosol following chemical hypoxia. In contrast, VHL-positive cells showed minimal caspase 9 activation, and absence of cytochrome c release under the same conditions. Caspase 8 was only minimally activated in both VHL-negative and -positive cells. In addition, VHL-positive cells displayed a striking up-regulation of Bcl-2 expression (5-fold) following chemical hypoxia. Antisense oligonucleotides to Bcl-2 significantly down-regulated Bcl-2 protein expression in VHL-positive cells and rendered them sensitive to apoptosis. Overexpression of Bcl-2 in VHL-negative cells conferred resistance to apoptosis. Our results suggest that VHL protects renal cells from apoptosis via Bcl-2-dependent pathways.

An association of cervical inflammation with high-grade cervical neoplasia in women infected with oncogenic human papillomavirus (HPV)

Previous reports of genital conditions, such as nonspecific genital infection/sore or vaginal discharge associated with cervical cancer (L. A. Brinton et al., J. Natl. Cancer Inst. (Bethesda), 79: 23-30, 1987; C. J. Jones et al., Cancer Res., 50: 3657-3662, 1990), suggest a possible link between either genital tract inflammation or changes in bacteria flora consistent with bacterial vaginosis (BV) and cervical cancer. To test whether changes in vaginal bacterial flora or the degree of cervical inflammation are associated with women having a human papillomavirus (HPV) infection or with women infected with oncogenic HPV having high-grade cervical lesions (high-grade squamous intraepithelial lesions or cancer), we conducted a case-control study of women <50 years old enrolled in the Costa Rican natural history study of HPV and cervical neoplasia. To test whether BV and inflammation were associated with HPV DNA positivity, Analysis 1 was restricted to women with no or mild (low-grade or equivocal) cytological abnormalities, and the degree of inflammation and Nugent score (a measure of BV) were compared between women infected (n = 220) and not infected (n = 130) with HPV. To test whether BV and inflammation were associated with high-grade lesions, Analysis 2 was restricted to women infected with oncogenic HPV, and the degree of inflammation and Nugent score were compared between women with (n = 95) and without (n = 158) high-grade cervical lesions. In Analysis 1, BV and cervical inflammation were not associated with HPV infection. In Analysis 2, BV was not associated with high-grade lesions. However, we found a marginally significant positive trend of increasing cervical inflammation associated with high-grade lesions in oncogenic HPV-infected women, (P(trend) = 0.05). Overt cervicitis was associated with a 1.9-fold increase in risk of high-grade lesions (95% confidence interval, 0.90-4.1). The results of this study suggest that cervical inflammation may be associated with high-grade lesions and may be a cofactor for high-grade cervical lesions in women infected with oncogenic HPV.

HPV co-factors related to the development of cervical cancer: results from a population-based study in Costa Rica

We examined factors associated with high-grade squamous intraepithelial lesions (HSIL) and cervical cancer among human papillomavirus (HPV)-infected women in a prevalent case-control study conducted within a population-based cohort of 10 077 women in Costa Rica. We compared 146 women with HPV-positive HSIL or cancer (HSIL/CA) against 843 HPV-positive women without evidence of HSIL/CA. Subjects completed a risk factor questionnaire. We evaluated the associations between exposures and HSIL/CA among women positive for any HPV and restricted to those positive for high-risk HPV types. Risk of HSIL/CA increased with increasing number of live births (P(trend)= 0.04). Women who smoked 6+ cigarettes/day had a RR for HSIL/CA of 2.7 (95% CI = 1.1-6.7) compared to non-smokers. Current use of barrier contraceptives was associated with a reduction in risk of HSIL/CA (RR = 0.39; 95% CI = 0.16-0.96). Sexual behaviour and a self-reported history of sexually transmitted diseases (STDs) other than HPV were not associated with HSIL/CA. Oral contraceptive use was associated with HSIL/CA among women with <3 pregnancies. Effects were similar in analysis restricted to women positive for high-risk HPV types. Among women positive for high-risk HPV types, 44% of HSIL/CA could be attributed to multiparity (>/=3 pregnancies) and/or smoking. Among HPV-positive women, multiparity and smoking are risk factors for HSIL/CA. Oral contraceptive use may be associated with HSIL/CA in subgroups of women.

Endoplasmic reticulum/cytosolic localization of von Hippel-Lindau gene products is mediated by a 64-amino acid region

Inactivation of the von Hippel-Lindau (VHL) tumor-suppressor gene causes both the familial cancer syndrome VHL disease and corresponding sporadic tumor types, including renal-cell carcinoma. Subcellular localization of VHL gene products was determined by indirect immunofluorescence. Both native and exogenously expressed VHL proteins displayed a cytoplasmic peri-nuclear immunostaining pattern, which co-localized with markers for the endoplasmic reticulum (ER). In addition, subcellular fractionation indicated that both native and exogenously expressed VHL products are found predominantly in the cytosolic compartment. Deletion analyses demonstrated that a 64-amino acid region of VHL (residues 114-177) is responsible for cytosolic as well as ER subcellular localization. Taken together, the immunostaining and biochemical fractionation studies suggest that VHL localizes to the cytosolic face of the ER. The relationship between VHL subcellular localization and VHL-associated ubiquitination was examined. Chimeric VHL-green fluorescent protein (GFP) products, which localized to the peri-nuclear region, were shown to undergo ubiquitination. VHL amino acids 114-177 were necessary and sufficient for this modification. Consistent with a role of VHL in ubiquitination, expression of VHL led to enhanced ubiquitination of cellular proteins, and amino acids 114-177 were also critical for this effect. Therefore, amino acids 114-177 were required for accurate VHL subcellular localization, ubiquitination of VHL-GFP products and VHL-dependent increases in cellular ubiquitination. Since mutations in this region of VHL are frequently detected in renal-cell carcinomas, these results suggest that proper VHL subcellular localization and associated ubiquitination functions may be necessary for VHL-mediated tumor suppression.

VHL induces renal cell differentiation and growth arrest through integration of cell-cell and cell-extracellular matrix signaling

Mutations in the von Hippel-Lindau (VHL) gene are involved in the family cancer syndrome for which it is named and the development of sporadic renal cell cancer (RCC). Reintroduction of VHL into RCC cells lacking functional VHL [VHL(-)] can suppress their growth in nude mice, but not under standard tissue culture conditions. To examine the hypothesis that the tumor suppressor function of VHL requires signaling through contact with extracellular matrix (ECM), 786-O VHL(-) RCC cells and isogenic sublines stably expressing VHL gene products [VHL(+)] were grown on ECMs. Cell-cell and cell-ECM signalings were required to elicit VHL-dependent differences in growth and differentiation. VHL(+) cells differentiated into organized epithelial sheets, whereas VHL(-) cells were branched and disorganized. VHL(+) cells grown to high density on collagen I underwent growth arrest, whereas VHL(-) cells continued to proliferate. Integrin levels were up-regulated in VHL(-) cells, and cell adhesion was down-regulated in VHL(+) cells during growth at high cell density. Hepatocyte nuclear factor 1alpha, a transcription factor and global activator of proximal tubule-specific genes in the nephron, was markedly up-regulated in VHL(+) cells grown at high cell density. These data indicate that VHL can induce renal cell differentiation and mediate growth arrest through integration of cell-cell and cell-ECM signals.

Complete nucleotide sequence and analysis of a novel human papillomavirus (HPV 84) genome cloned by an overlapping PCR method

Molecular diagnosis of human papillomaviruses (HPVs) in cervicovaginal samples reveals a plethora of known and novel HPV genomes. We describe the use of an overlapping PCR method to clone and analyze the complete genome of HPV 84 from cervicovaginal cells obtained from a 21-year-old Caucasian female with a normal Pap smear. The 7948-bp complete nucleotide sequence of HPV 84 was determined from five overlapping PCR products by sequence walking. A BLAST homology search demonstrated that HPV 84 was most closely related to HPV 61 (89%), HPV 72 (86%), and HPV 83 (85%) by nucleotide sequence analysis of the L1 open reading frame, placing it in the HPV genome homology group A3. Previously, this virus had been identified as Pap155. Based on extensive epidemiological data, HPV 84 is a highly prevalent genital papillomavirus primarily detected in normal and HIV-infected women.

A prospective study of human papillomavirus (HPV) type 16 DNA detection by polymerase chain reaction and its association with acquisition and persistence of other HPV types

Human papillomavirus (HPV)-16 causes about half the cases of cervical cancer worldwide and is the focus of HPV vaccine development efforts. Systematic data are lacking as to whether the prevention of HPV-16 could affect the equilibrium of infection with other HPV types and thus alter the predicted impact of vaccination on the occurrence of cervical neoplasia. Therefore, the associations of HPV-16 detection with subsequent acquisition of other HPV types and with the persistence of concomitantly detected HPV types were examined prospectively among 1124 initially cytologically normal women. Preexisting HPV-16 was generally associated with an increased risk for subsequent acquisition of other types. HPV-16 did not affect the persistence of concomitant infections, regardless of type. These findings suggest that the prevention or removal of HPV-16 is not likely to promote the risk of infection with other types, a theoretical concern with current vaccination efforts.

The relation of type 2 diabetes and cancer

Increasing evidence indicates that individuals with type 2 diabetes (diabetes) are at elevated risk for several common human malignancies, including cancers of the colon, breast, endometrium, pancreas, and liver. In particular, the consistent positive results reported by prospective investigations make it unlikely that methodologic issues, occult tumors, or chance results could explain the findings. Since diabetes and impaired fasting glucose together affect >25% of Americans above age 50, even a moderate etiologic association (e.g., relative risk = 1.5) would explain >10% of involved malignancies. Laboratory studies have suggested biologically plausible mechanisms. Insulin, for example, is typically at high levels during the development and early stages of diabetes. Activation of the insulin receptor by its ligand, or cross-activation of the insulin-like growth factor-I receptor, has been shown to be mitogenic and promote tumorigenesis in various model systems. A "unifying concept," in fact, holds that hyperinsulinemia may underlie the cancer associations of several additional risk factors, including high waist circumference, visceral fat, waist-to-hip ratio, body mass index, sedentary lifestyle, and energy intake. In this review, we assess current evidence regarding the relation of type 2 diabetes with cancer, and evaluate the findings in terms of well-accepted criteria for establishing causality.

The von Hippel-Lindau tumor suppressor gene protects cells from UV-mediated apoptosis

The familial cancer syndrome, von Hippel-Lindau (VHL) disease, characterized by a predisposition to renal cell carcinoma and certain other tumor types, is caused by mutational inactivation of the VHL tumor suppressor gene. Loss of VHL gene function is detected also in the vast majority of sporadic renal cell carcinomas. Previous reports have determined a protective role for VHL in response to serum withdrawal and glucose deprivation. In this study, the effect of UV irradiation on VHL-negative and VHL-positive renal carcinoma cells was examined. VHL-negative 786-O renal carcinoma cells underwent apoptosis following UV irradiation. In contrast, reintroduction of wild-type VHL expression protected 786-O cells from UV-mediated cell death. p53 and Bax levels were equivalent in VHL-negative and VHL-positive 786-O cells. Strikingly, cyclin-dependent kinase inhibitors p21 and p27 underwent proteasome-dependent degradation in VHL-negative 786-O cells following UV treatment. However, p21 and p27 protein levels were stable in VHL-positive cells. Also, levels of the anti-apoptotic proteins, Bcl-2 and Bcl-xL were elevated in VHL-positive cells, consistent with the protection from apoptotic stimuli. UV treatment led to increased S phase in VHL-negative, but not VHL-positive cells. Thus, following UV irradiation, diminution of p21 and p27 levels resulted in a hyperproliferative state in VHL-negative cells, leading to apoptosis. These results suggest that loss of VHL function promotes apoptosis and may provide selective pressure toward cells that are able to escape apoptosis, leading to tumorigenesis.

Elongin BC complex prevents degradation of von Hippel-Lindau tumor suppressor gene products

Inactivation of the von Hippel-Lindau (VHL) tumor suppressor gene causes the familial cancer syndrome, VHL disease, characterized by a predisposition to renal cell carcinoma and other tumor types. Loss of VHL gene function also is found in a majority of sporadic renal carcinomas. A preponderance of the tumor-disposing inherited missense mutations detected in VHL disease are within the elongin-binding domain of VHL. This region mediates the formation of a multiprotein VHL complex containing elongin B, elongin C, cul-2, and Rbx1. This VHL complex is thought to function as an E3 ubiquitin ligase. Here, we report that VHL proteins harboring mutations which disrupt elongin binding are unstable and rapidly degraded by the proteasome. In contrast, wild-type VHL proteins are directly stabilized by associating with both elongins B and C. In addition, elongins B and C are stabilized through their interactions with each other and VHL. Thus, the entire VHL/elongin complex is resistant to proteasomal degradation. Because the elongin-binding domain of VHL is frequently mutated in cancers, these results suggest that loss of elongin binding causes tumorigenesis by compromising VHL protein stability and/or potential VHL ubiquitination functions.

Liver cell-specific transcriptional regulation of connexin32

Gap junctional intercellular communication facilitates liver homeostasis and growth control in the liver. The major gap junction protein expressed by hepatocytes is connexin32 (Cx32) and non-parenchymal hepatic cells do not express this gene. We investigated the regulation of Cx32 transcription by trans-activating factors in liver cells. Transient transfection assays using deletions of the rat Cx32 promoter (nt -753 to -33) linked to the luciferase gene were performed in MH1C1 rat hepatoma cells that express endogenous Cx32 compared with WB-F344 rat liver epithelial cells that do not. The basal promoter element was located within nt -134 to -33 and was 1.4-fold more active in MH1C1 cells than WB-F344 cells whereas the entire promoter fragment (nt -754 to -33) was four-fold more active in MH1C1 cells. Specific nuclear protein-DNA complexes that bound to Sp1 consensus sites within the basal promoter were formed using nuclear extracts from both types of cells. Additional promoter sequences increased promoter activity more strongly in MH1C1 cells than WB-F344 cells and this was correlated with the binding of hepatocyte nuclear factor-1 (HNF-1) to two HNF-1 consensus sites centered at -187 and -736. Expression of HNF-1 and binding to these elements was only observed with MH1C1 cells. Other specific protein-DNA complexes were formed, however, that included YY-1- and NF-1-containing complexes, but these were not related to promoter activity. Dexamethasone increased Cx32 promoter activity and expression in MH1C1 cells, but had little effect in WB-F344 cells and did not alter protein-DNA complex formation. These data suggest that Sp1 is responsible for Cx32 promoter basal activity, that HNF-1 determines the cell-specific expression of Cx32, and that dexamethasone increases Cx32 expression through other mechanisms.

Population-based study of human papillomavirus infection and cervical neoplasia in rural Costa Rica

BACKGROUND

Human papillomavirus (HPV) is the main cause of cervical neoplasia. Because few population-based studies have investigated the prevalence of type-specific infection in relation to cervical disease, we studied a high-risk population, estimating the prevalence of HPV infection and the risk associated with various HPV types.

METHODS

We screened 9175 women in Guanacaste, Costa Rica, to obtain a referent standard final diagnosis, and tested 3024 women for more than 40 types of HPV with a polymerase chain reaction-based system.

RESULTS

Among women with normal cytology, HPV infections peaked first in women younger than 25 years, and they peaked again at age 55 years or older with predominantly non-cancer-associated types of HPV and uncharacterized HPV types. Low-grade squamous intraepithelial lesions (LSILs) (n = 189) decreased consistently with age. The prevalence of high-grade squamous intraepithelial lesions (HSILs) (n = 128) peaked first around age 30 years and again at age 65 years or older. Seventy-three percent of LSILs were HPV positive, with HPV16 being the predominant type (16% of positive subjects). HPV was found in 89% of HSILs and 88% of cancers, with HPV16 being strongly predominant (51% and 53% of positive subjects). Virtually all HSILs and cancers had cancer-associated HPV types, with high odds ratios (ORs) and attributable fractions around 80%. Risk for HPV16 was particularly high (OR for HSILs = 320, 95% confidence interval [CI] = 97-1000; OR for cancer = 710, 95% CI = 110-4500).

CONCLUSIONS

We confirm the early decline of HPV infection with age but note increased prevalence after menopause, which could be related to a second peak of HSILs, an observation that warrants further investigation. At least 80% of HPVs involved in cervical carcinogenesis in this population have been characterized. Polyvalent vaccines including the main cancer-associated HPV types may be able to prevent most cases of cervical disease in this region.

Human papillomavirus and the risk of cervical cancer

Human papillomavirus (HPV) is now recognized as the driving force behind the dysregulation of the cell cycle that underlies cervical malignant transformation. Although nearly all cervical cancers contain HPV genomes, the vast majority of HPVs are not oncogenic but merely induce benign lesions. Because progressive abnormalities take at least a decade to develop into invasive cancers, young women with low-grade lesions can often be managed with watchful waiting rather than ablative therapy.

Seroreactivity to human papillomavirus types 16, 18, 31, and 45 virus-like particles in a case-control study of cervical squamous intraepithelial lesions

Serum IgG antibodies to human papillomavirus (HPV) types 16, 18, 31, and 45 virus-like particles were measured in a nested case-control study of cervical squamous intraepithelial lesions. HPV-16 seroreactivity was strongly associated with HPV-16 DNA detection (odds ratio, 9.0; 95% confidence interval, 4.4-19.4), and similar type specificity was observed for HPV-31 and -45. In contrast, seroreactivity to any type was associated with elevated seroreactivity to all others. Among cases and controls, HPV-16 showed the highest seroprevalence, with 23.8% of 80 cases and 10.5% of 258 controls seroreactive to HPV-16 alone, and another 27.5% and 5.4%, respectively, seroreactive to HPV-16 plus other types. Overall, 24 (30.0%) cases and 17 (6.6%) controls were seroreactive to multiple types. These data suggest that seroreactivity to a given type reflects mainly type-specific HPV infection as measured by DNA detection and may also signal past exposure to other types that are now only serologically detected.

Adeno-associated virus and development of cervical neoplasia

Evidence from several sources has suggested that adeno-associated virus (AAV) infection might protect against cervical cancer, in part, by interfering with human papillomavirus (HPV)-induced tumorigenesis. Detection of AAV type 2 (AAV-2) DNA in cervical tissues has been reported. However, there have been few in vivo studies of women with cervical HPV infection or neoplasia, and these have reported inconsistent results. Therefore, we used polymerase chain reaction (PCR) assays targeted to the AAV-2 rep and cap genes to test tissue specimens from women in an epidemiological study of cervical neoplasia in Jamaica. We tested 105 women with low-grade cervical intraepithelial neoplasia (CIN-1), 92 women with CIN-3/carcinoma in situ or invasive cancer (CIN-3/CA), and 94 normal subjects. PCR amplification of human beta-globin DNA was found in almost all cervical specimens, indicating that these materials were adequate for PCR testing. The prevalence of HPV DNA, determined by HPV L1 consensus primer PCR was, as expected, strongly associated with presence and grade of neoplasia. Each of the AAV PCR assays detected as few as 10 copies of the virus genome. However, none of the 291 cervical specimens from Jamaican subjects tested positive for AAV DNA. Negative AAV PCR results were also obtained in tests of cervical samples from 79 university students in the United States. Exposure to AAV was assessed further by serology. Using a whole virus AAV-2 sandwich enzyme-linked immunosorbent assay, we found no relationship between AAV antibodies and presence or grade of neoplasia in either the Jamaican study subjects or women enrolled in a U.S. cervical cancer case (n = 74) -control (n = 77) study. Overall, the data provide no evidence that AAV infection plays a role in cervical tumorigenesis or that AAV commonly infects cervical epithelial cells.

Detection of human papillomavirus DNA in cytologically normal women and subsequent cervical squamous intraepithelial lesions

BACKGROUND

Human papillomavirus (HPV) infection has been strongly associated with cervical carcinoma and its cytologic precursors, squamous intraepithelial lesions (SIL). We investigated the risk of SIL prospectively following polymerase chain reaction (PCR)-based DNA testing for a wide range of genital HPV types in a cohort of initially cytologically normal women, to clarify the role of HPV in the etiology of SIL.

METHODS

Starting in April 1989, 17,654 women who were receiving routine cytologic screening at Kaiser Permanente (Portland, OR) were followed for the development of incident SIL. During follow-up, 380 incident case patients and 1037 matched control subjects were eligible for this nested case-control study. Cervical lavages collected at enrollment and, later, at the time of case diagnosis (or the corresponding time for selection of control subjects) were tested for HPV DNA using a PCR-based method. The data were analyzed as contingency tables with two-sided P values or, for multivariable analyses, using odds ratios (ORs) with 95% confidence intervals (CIs).

RESULTS

In comparison with initially HPV-negative women, women who tested positive for HPV DNA at enrollment were 3.8 times (95% CI = 2.6-5.5) more likely to have low-grade SIL subsequently diagnosed for the first time during follow-up and 12.7 times more likely (95% CI = 6.2-25.9) to develop high-grade SIL. At the time of diagnosis, the cross-sectional association of HPV DNA and SIL was extremely strong (OR = 44.4 and 95% CI = 24.2-81.5 for low-grade SIL and OR = 67.1 and 95% CI = 19.3-233.7 for high-grade SIL). HPV16 was the virus type most predictive of SIL, even low-grade SIL.

CONCLUSIONS

These findings are consistent with the hypothesis that HPV infection is the primary cause of cervical neoplasia. Furthermore, they support HPV vaccine research to prevent cervical cancer and efforts to develop HPV DNA diagnostic tests.

Prevalence and predictors of squamous cell abnormalities in Papanicolaou smears from women infected with HIV-1. Women's Interagency HIV Study Group

BACKGROUND

Cervical neoplasia occurs with increased frequency among women infected with HIV-1.

OBJECTIVE

To characterize prevalence of and risk factors for abnormal cervical cytology among women with HIV and to compare them to uninfected women.

METHODS

Baseline cervical cytology was obtained from 1713 women seropositive for HIV and 482 at-risk control women who were enrolled in the Women's Interagency HIV Study, a multicenter prospective cohort study conducted in six U.S. cities. Associations with sociodemographic, medical, and sexual variables were assessed by Fisher's exact test, Mantel extension test, and logistic regression analysis.

RESULTS

Cervical cytology was abnormal in 38.3% of HIV-infected women (atypical squamous cells of uncertain significance [ASCUS] 20.9%, low-grade squamous cells of uncertain significance [LSIL] 14.9%, high-grade squamous cells of uncertain significance [HSIL] 2.3%, cancer 0.2%) and 16.2% of HIV-uninfected women (ASCUS 12.7%, LSIL 2.3%, HSIL 1.2%, cancer 0.0%). Risk factors for any abnormal cytology in multivariate analysis included HIV infection, CD4 cell count, HIV RNA level, detection of human papillomavirus (HPV), a prior history of abnormal cytology, employment, and number of male sex partners within 6 months of enrollment. Prior abortion was associated with a decreased risk of cytologic abnormality.

CONCLUSIONS

Cervical cytologic abnormalities were frequent among women infected with HIV, although high-grade changes were found in only 2.5%. Factors linked to sexual and reproductive history, HPV infection, and HIV disease all influenced risk.

"ASCUS, rule out HSIL": cytologic features, histologic correlates, and human papillomavirus detection

Risk factors, cytologic and histopathologic features, and human papillomavirus (HPV) detection associated with 75 cervical smears classified as atypical squamous cells of undetermined significance, rule out high-grade squamous intraepithelial lesion (ASCUS, rule out HSIL) were reviewed. Cases were identified in a pathology panel review of material collected from 1953 women participating in a 5-year prospective study of HPV infection and squamous intraepithelial lesions at Kaiser Permanente, Portland, Oregon, sponsored by the National Cancer Institute. Initial abnormal smears diagnosed as ASCUS, rule out HSIL by one panelist or diagnosed as ASCUS by one pathologist and as HSIL by another were included. The 75 ASCUS, rule out HSIL smears identified were examined again by two pathologists after the study. These cases were compared with cases of ASCUS, not otherwise specified (ASCUS, NOS) and HSIL identified in the same group of 1953 women. Findings in ASCUS, rule out HSIL included tissue fragments (21%); atypical immature metaplasia (17%); atypical mature metaplasia (15%); small atypical cells (9%); and atypical repair (4%). A final patient classification of HSIL, reflecting all available data, was assigned to 11 (24%) of 46 women with ASCUS, rule out HSIL and to 1(1%) of 80 women with ASCUS, NOS in the original review (P < .001). Detection of oncogenic HPV types at diagnosis in ASCUS, rule out HSIL; ASCUS, NOS; and HSIL was similar, but data were unavailable for many subjects. Among women not tested at diagnosis, enrollment testing (1 to 4 years earlier) revealed that HPV detection in women with ASCUS, rule out HSIL was intermediate in frequency between ASCUS, NOS and HSIL. These data suggest that ASCUS, rule out HSIL is a distinct diagnosis from ASCUS, NOS because it is more often associated with an underlying HSIL. Consequently, women with ASCUS, rule out HSIL should be referred for colposcopic examination.

Soluble interleukin 2 receptor levels and cervical neoplasia: results from a population-based case-control study in Costa Rica

Progression from infection with human papillomavirus (HPV) to cervical cancer in some women is thought to involve a permissive host environment, one in which immune response is mobilized in an inappropriate manner. In a previous study (A. Hildesheim et al., Cancer Epidemiol. Biomark. Prev., 6: 807-813, 1997), increasing levels of soluble interleukin 2 receptor (sIL-2R), a known proxy for general immune activation, was found to be positively associated with increasing levels of cervical neoplasia. We attempted to confirm this finding by conducting a nested case-control study of 478 women within a 10,000-woman population-based cohort in Costa Rica. We selected for the study all of the women diagnosed (at enrollment into the cohort) with: (a) low-grade squamous intraepithelial lesions (LSIL, n = 191); (b) high-grade squamous intraepithelial lesions (HSIL, n = 130); or (c) cancer (n = 37). Controls were 120 cytologically normal, HPV-negative women selected from a random sample of the entire cohort. A questionnaire was administered to participants to elicit information on cervical cancer risk factors. All of the women received a pelvic examination during which cervical cells were collected and used for HPV DNA testing by PCR. Blood samples were also collected. Plasma obtained from the blood samples was tested for sIL-2R levels by ELISA. Results indicated that sIL-2R levels increased with age. Among controls, we observed that 44.3% of women over the age of 50 had high levels of sIL-2R (defined as >735 units/ml) compared with 15.8% of women <30 years of age (P = 0.008). When women with cervical disease (LSIL+) were compared with controls, women in the upper quartile of the sIL-2R distribution had an age-adjusted odds ratio (OR) of 2.1 [95% confidence interval (CI), 1.1-4.1]. Comparing each advancing state of neoplasia with its precursor, we found that women with LSIL had higher sIL-2R levels than controls (OR for upper quartile of sIL-2R, 2.3; 95% CI, 1.1-5.2; comparing LSIL cases with controls); women diagnosed with HSIL were similar to the LSIL group (OR for upper quartile of sIL-2R, 1.1; 95% CI, 0.5-2.4; comparing HSIL cases with LSIL cases); and those with cancer had higher sIL-2R levels than subjects with an HSIL diagnosis (OR for upper quartile of sIL-2R = 1.8; 95% CI, 0.5-7.1; comparing cancer cases with HSIL cases). These data suggest that among our study subjects, sIL-2R levels most likely rise as a response to the events of infection and cancerous invasion, but that sIL-2R levels are unlikely to be predictive of disease progression among women with LSIL.

Regulation of connexin32 and connexin43 gene expression by DNA methylation in rat liver cells

Gap junction proteins (connexins) are expressed in a cell-specific manner and expression is often reduced in neoplastic cells. We investigated the mechanisms of connexin32 (Cx32) and connexin43 (Cx43) expression in hepatic cells using MH1C1 rat hepatoma cells and freshly isolated, adult rat hepatocytes that express Cx32 but not Cx43 and WB-F344 rat liver epithelial cells that express Cx43 but not Cx32. Southern blotting after DNA restriction with MspI and HpaII indicated that two MspI/HpaII restriction sites in the Cx32 promoter (positions -147 and -847) were methylated in WB-F344 cells, but not in MH1C1 cells or hepatocytes. In contrast, an MspI/HpaII restriction site in the Cx43 promoter (position -38) was methylated in MH1C1 cells, but not in WB-F344 cells or hepatocytes. Transient transfection of the cell lines with connexin promoter-luciferase constructs indicated that the Cx32 promoter was 7-fold more active in MH1C1 cells and the Cx43 promoter was 5-fold more active in WB-F344 cells. These results suggest that transcription of Cx32 and Cx43 in hepatic cells is controlled by promoter methylation and by cell-specific transcription factors. Similar mechanisms may be involved in the reduced expression of these genes frequently observed in neoplastic cells.

Transplanted hepatocytes proliferate differently after CCl4 treatment and hepatocyte growth factor infusion

To understand regulation of transplanted hepatocyte proliferation in the normal liver, we used genetically marked rat or mouse cells. Hosts were subjected to liver injury by carbon tetrachloride (CCl4), to liver regeneration by a two-thirds partial hepatectomy, and to hepatocellular DNA synthesis by infusion of hepatocyte growth factor for comparative analysis. Transplanted hepatocytes were documented to integrate in periportal areas of the liver. In response to CCl4 treatments after cell transplantation, the transplanted hepatocyte mass increased incrementally, with the kinetics and magnitude of DNA synthesis being similar to those of host hepatocytes. In contrast, when cells were transplanted 24 h after CCl4 administration, transplanted hepatocytes appeared to be injured and most cells were rapidly cleared. When hepatocyte growth factor was infused into the portal circulation either subsequent to or before cell transplantation and engraftment, transplanted cell mass did not increase, although DNA synthesis rates increased in cultured primary hepatocytes as well as in intact mouse and rat livers. These data suggested that procedures causing selective ablation of host hepatocytes will be most effective in inducing transplanted cell proliferation in the normal liver. The number of transplanted hepatocytes was not increased in the liver by hepatocyte growth factor administration. Repopulation of the liver with genetically marked hepatocytes can provide effective reporters for studying liver growth control in the intact animal.

Viral characteristics of human papillomavirus infection and antioxidant levels as risk factors for cervical dysplasia

Genital human papillomavirus (HPV) infection is the major causal factor of cervical intraepithelial neoplasia (CIN). The potential role of nutrition as an additional, independent risk factor for CIN has not been appropriately addressed in the context of HPV. This case-control study evaluated the etiologic role of HPV in terms of viral type and load and examined the association between CIN and plasma levels of micronutrients adjusting for HPV. Cases (n = 378) with histo-pathologically confirmed CIN and controls (n = 366) with no history of abnormal Pap smears were recruited from colposcopy and gynecology clinics, respectively. Risk of CIN was significantly increased among women who were infected with multiple HPV types (odds ratio [OR] = 21.06), a high viral load (OR = 13.08) and HPV 16 (OR = 62.49). After adjusting for HPV positivity and demographic factors, there was an inverse correlation between plasma alpha-tocopherol and risk of CIN (OR = 0.15). Plasma ascorbic acid was protective at a high level of > or = 0.803 mg/dl (OR = 0.46). CIN was not associated with plasma retinol and beta-carotene levels. The effect of genital HPV infection on CIN development is highly influenced by oncogenic viral type and high viral load. Vitamins C and E may play an independent protective role in development of CIN that needs to be confirmed in prospective studies.

Development of a multi-item scale to quantitatively assess sexual behaviors and the transmission of high- and low-risk human papillomaviruses

BACKGROUND

Epidemiologic research is frequently hindered by the inherent difficulty in quantifying the risk of sexually transmitted disease (STD) acquisition associated with individual patterns of sexual behavior.

GOAL OF THE STUDY

To develop a quantitative sexual behavior risk scale and demonstrate its predictive validity in an assessment of risk factors for incident infection with human papillomaviruses (HPVs).

STUDY DESIGN

Data from a prospective study of HPV infection in female university students was used to generate quantitative multi-item sexual behavior scales which were used in Cox regression analyses.

RESULTS

Although risk was incurred both in casual sexual encounters and in noncasual relationships, risk in these contexts were only weakly correlated. The construction of separate measurement scales was performed.

CONCLUSIONS

Improved precision of measurement of STD risk demonstrated that significant risk was associated with different patterns of sexual behavior and was incurred in both casual and/or noncasual relationships. Scores on the sexual behavior risk scales were highly predictive of incident infection with HPV types of both high and low oncogenic potential.

HPV 16 and cigarette smoking as risk factors for high-grade cervical intra-epithelial neoplasia

Although genital human papillomavirus (HPV) infection is well established as the etiologic agent for cervical intraepithelial neoplasia (CIN), little is known about the cofactors involved in the development of high-grade lesions or the progression of low-grade to high-grade lesions. In our study of HPV-infected women with CIN (163 CIN I, 51 CIN II and 44 CIN III), women with CIN II or III were compared with those with CIN I for risk factors associated with high-grade lesions. After controlling for age, education, ethnicity and frequency of Pap smear screening, infection with HPV 16, but not high viral load or infection with multiple types, was associated with high-grade lesions (OR for CIN II = 11.96, OR for CIN III = 23.74). Risk of CIN III, but not CIN II, increased with number of cigarettes smoked per day (ORs = 1.49 and 3.35 for < or = 10 and > 10 cigarettes per day, respectively) and decreased with frequency of condom use during sex (ORs = 0.60 and 0.32 for women who used condoms occasionally/sometimes and most/all of the time, respectively). There were no associations between high-grade lesions and plasma levels of micronutrients (retinol, beta-carotene, alpha-tocopherol and reduced ascorbic acid). Our results indicate that infection with HPV 16 is associated with high-grade lesions. Additional cofactors, such as cigarette smoking, may be required as a carcinogen to advance HPV-infected cells toward neoplastic progression.

A second major native von Hippel-Lindau gene product, initiated from an internal translation start site, functions as a tumor suppressor

The von Hippel-Lindau (VHL) tumor suppressor gene is inactivated in both sporadic and inherited clear cell renal carcinoma associated with VHL disease. We have identified two distinct native products of the human VHL gene, with apparent molecular masses of 24 and 18 kDa. The 18-kDa VHL protein was more abundant in nearly all cell lines examined. Reintroduction of the 18-kDa VHL gene product into renal carcinoma cells lacking wild-type VHL protein led to down-regulation of vascular endothelial growth factor (VEGF) mRNA and glucose transporter GLUT1 protein and suppressed tumor formation in nude mice. The 18-kDa VHL protein also demonstrated binding to elongins B and C. In an in vitro assay, the second in-frame AUG codon present in VHL mRNA was shown to be necessary and sufficient for production of the 18-kDa VHL protein, consistent with an internal translation mechanism. These data provide evidence for a second major VHL gene product, which contains the functional domains of the VHL gene. Moreover, these results indicate that internal translation initiation is an important mechanism for production of the major VHL protein.

A nested case-control study of dietary factors and the risk of incident cytological abnormalities of the cervix

Several earlier case-control studies reported inverse associations of cervical squamous intraepithelial lesions (SIL) with high dietary or biomarker levels of carotenoids, folate, and vitamins C and E. However, most studies did not measure the primary causal factor, cancer-associated genital human papillomaviruses (HPV), now detected by sensitive viral DNA tests. This nested case-control study assessed whether high dietary intakes of these nutrients, plus zinc and vitamin A, reduced SIL risk in cancer-associated HPV DNA-positive women. Using a 60-item food-frequency questionnaire, nutrient estimates were obtained for 33 incident cases with high-grade lesions, 121 with low-grade lesions, 97 with equivocal SIL, and 806 cytologically normal controls sampled from a large prospective cohort study. Baseline cervicovaginal lavages were tested for HPV DNA by the polymerase chain reaction. Among DNA-positive cases (n = 68) and controls (n = 69), age-adjusted odds ratios (ORs) of SIL in the highest vs. the lowest nutrient quartiles were 1.4 [95% confidence interval (CI) = 0.5-4.2] for vitamin A, 0.6 (CI = 0.2-2.0) for beta-carotene, 1.3 (CI = 0.4-3.6) for vitamin C, 1.0 (CI = 0.4-3.6) for vitamin E, 0.7 (CI = 0.3-2.1) for folate, and 0.8 (CI = 0.3-2.2) for zinc. ORs in HPV DNA-negative women approximated 1.0, with the exception of vitamin E (OR = 0.5, CI = 0.3-0.9). These results do not support a protective role for the above nutrients against low-grade or equivocal SIL, which constituted the majority of diagnoses in this study.

Prevalence, risk factors, and accuracy of cytologic screening for cervical intraepithelial neoplasia in women with the human immunodeficiency virus

OBJECTIVES

The objective was to evaluate the sensitivity and specificity of cervical cytology in women infected with the human immunodeficiency virus (HIV), risk factors for abnormal cytology in HIV-infected and uninfected women, and risk factors for histologic diagnosis of cervical intraepithelial neoplasia (CIN) in HIV-infected women.

METHODS

Methods included a cross-sectional analysis of cervical cytology, colposcopic impression, and histology in 248 HIV-infected women and multivariate analyses of risk factors for abnormal cytology in 253 HIV-infected and 220 uninfected women and risk factors for CIN in 186 HIV-infected women.

RESULTS

The sensitivity and specificity of cytology for all CIN grades were 0.60 and 0.80 and, for high-grade CIN, 0.83 and 0.74. The prevalence of abnormal cytology was 32.9% in HIV-infected and 7.6% in HIV-negative women. Independent risk factors for abnormal cytology were immunodeficiency [odds ratio (OR) 8-17, P < 0.001] and human papillomavirus (HPV) infection (OR = 5, P < 0.001). The prevalence of CIN on histology was 32% in HIV-infected women, and the only independent risk factor for CIN was oncogenic HPV type (OR = 5, P = 0.005).

CONCLUSION

Given the high prevalence of abnormal cytology and CIN in HIV-infected women, cytologic screening has significant limitations. Both immunodeficiency and type of HPV infection are important risk factors.

Natural history of cervicovaginal papillomavirus infection in young women

BACKGROUND

Genital human papillomavirus (HPV) infection is highly prevalent in sexually active young women. However, precise risk factors for HPV infection and its incidence and duration are not well known.

METHODS

We followed 608 college women at six-month intervals for three years. At each visit, we collected information about lifestyle and sexual behavior and obtained cervicovaginal-lavage samples for the detection of HPV DNA by polymerase chain reaction and Southern blot hybridization. Pap smears were obtained annually.

RESULTS

The cumulative 36-month incidence of HPV infection was 43 percent (95 percent confidence interval, 36 to 49 percent). An increased risk of HPV infection was significantly associated with younger age, Hispanic ethnicity, black race, an increased number of vaginal-sex partners, high frequencies of vaginal sex and alcohol consumption, anal sex, and certain characteristics of partners (regular partners having an increased number of lifetime partners and not being in school). The median duration of new infections was 8 months (95 percent confidence interval, 7 to 10 months). The persistence of HPV for > or =6 months was related to older age, types of HPV associated with cervical cancer, and infection with multiple types of HPV but not with smoking. The risk of an abnormal Pap smear increased with persistent HPV infection, particularly with high-risk types (relative risk, 37.2; 95 percent confidence interval, 14.6 to 94.8).

CONCLUSIONS

The incidence of HPV infection in sexually active young college women is high. The short duration of most HPV infections in these women suggests that the associated cervical dysplasia should be managed conservatively.

Stringent criteria for histological diagnosis of koilocytosis fail to eliminate overdiagnosis of human papillomavirus infection and cervical intraepithelial neoplasia grade 1

Overdiagnosis of HPV infection in cervical biopsies results in increased health care costs and unnecessary surgical procedures. Stringent criteria for histological diagnosis of koilocytosis were evaluated, using molecular detection of HPV DNA (polymerase chain reaction and Southern blot hybridization) as gold standard. Colposcopic biopsy specimens from 511 patients were studied, including 76 with referral diagnoses of negative cervix and 241 with CIN 1 or koilocytosis. Referral diagnoses for low-grade lesions failed to distinguish between HPV-infected and uninfected patients. False-positive rate for prediction of HPV infection was 74.8%. Biopsy specimens reevaluated using stringent diagnostic criteria showed increasing prevalence of HPV infection among patients whose biopsy specimens showed negative (43.7%), minimal (52.4%), or definite (69.5%) features of koilocytosis (P = .001). Similarly, subjects infected with high viral load or oncogenic HPV infection were more likely to be identified (P = .004 and .04, respectively). Despite increased predictive value of stringent diagnostic criteria, significant number of patients diagnosed as having CIN 1/koilocytosis (34.0%) did not in fact have HPV infection. Because most low-grade lesions spontaneously regress, patients with histological diagnosis of CIN 1 or HPV infection should be observed for a period of several months before definitive ablative treatment is undertaken.