Human papillomavirus genotype as a predictor of persistence and development of high-grade lesions in women with minor cervical abnormalities

Differences and changes in human papillomavirus type 16 variant status in human immunodeficiency virus-positive adults are not uncommon

Human papillomavirus type 16 (HPV-16) genotype variants have been the subject of several investigations, but study participants have rarely been sampled more than once. In this study, among a cohort of human immunodeficiency virus (HIV)-infected adults, HPV-16 variants were investigated in samples collected concurrently from the anus and cervix, as well as in serial samples collected from the same anatomical site at 12-month intervals. HPV-16 variants in stored extracts of cervical and anal samples were determined from subjects with multiple visits and at least one sample positive for HPV-16. Seven polymorphic nucleotide positions within the E6 region were analysed by pyrosequencing to determine genotype variants. Of 364 samples examined, 176 anal and 39 cervical swabs from 84 different subjects yielded unequivocal sequences of eight major HPV-16 variants. Eight samples contained probable novel HPV-16 variants and in one sample two variants were detected. In eight out of 29 (27.6%) anal-cervical sample pairs positive for HPV-16, discordant variants were found. From 57 anal and nine cervical sample series of HPV-16-positive samples, a change in HPV-16 variant status over time was seen in nine (13.6%) instances (seven anal and two cervical) from eight different participants. Changes in HPV-16 variants in HIV-infected adults were seen most frequently when different anatomical sites were sampled, but were also observed over time.

Association of HPV16 E6 variants with diagnostic severity in cervical cytology samples of 354 women in a US population

It has been suggested that DNA sequence variants of HPV16 contribute to differences in the behavior of individual cervical lesions. To address this question, we have analyzed the association of HPV16 variants with diagnostic severity in 354 HPV16-positive Oklahoman women. HPV16 variant status was determined by PCR amplification and DNA sequencing of the E6 open reading frame. European sequences were identified in 86% of samples and 14% were non-European. Of the 51 non-European cases, 61% were Asian-American, 23% African and 16% were Native American variants. European prototype and related variants were present in comparable numbers (43% each) but the relative proportion of each differed with diagnostic category. In general, the proportion of European variants and non-European variants increased with diagnostic severity while the European prototype decreased. When adjusted for age and race (white, black or Hispanic), the increased risk for carcinoma/severe dysplasia for non-European variants was statistically significant with an odds ratio of 3.8 (1.3-10.7). However, the analogous comparison for the European variants, although also showing increased association with carcinoma/severe dysplasia, did not reach statistical significance (OR = 1.6 (95% CI 0.7-3.6). Overall, HPV16 European sequences (both prototype and related variants), were predominant in Oklahoman women including those with cancers. This suggests that while there appear to be differences among the HPV16-variant categories in risk for progression to invasive cancer, all variant categories are associated with the development of invasive cancer.

Epidemiology and genotype distribution of human papillomavirus (HPV) in women of Sardinia (Italy)

The human papillomavirus (HPV) infection is necessary for the development of cervical cancer. Our study aims to evaluate the rate of HPV circulation in our population, to identify the prevalent genotypes and to establish correlation with cervical abnormalities. Furthermore, the awareness of women about HPV issues was investigated. This study included 864 women attending the Oncologic Prevention Service for their routine Pap test screening or the Health Promotion Mother-Child Service for counselling about sexual activity, from July 2006 to September 2007. All the participants gave their informed consent to be enrolled in the study and were invited to fill in a questionnaire about the socio-cultural state, sexual activity and awareness about HPV. The women samples were tested for HPV-DNA and HPV genotypes: any type of HPV-DNA was detected in 31.0% of the women; single or multiple infections sustained by HPV-16 or HPV-18 represented 43.5% of all HPV infections, accounting for infections in 11.8% of the recruited women. The HPV and high-risk HPV (HR-HPV) prevalence significantly declined in women older than 46 years. The Pap test result was available in 490 women; 48.1% of the Pap test positive women had also an HPV infection and among these 22.7% were infected by HPV-16 and/or HPV-18 genotype, while 51.9% (94/181) were HPV negative. The analysis by binary logistic regression showed that genotype 16 and/or 18 is a risk factor for the Pap positive test with a odds ratio (OR) of 2.9 (95% C.I. 1.4-5.9) and 3.6 (95% C.I. 1.58-8.42) respectively, while age is a protective factor (OR 0.97, C.I. 95% 0.96-0.99); furthermore, the mean age at the first sexual intercourse and the mean number of partners since the beginning of sexual activity, were statistically associated with the risk of HPV infection. More than half of women were aware about HPV, its sexual transmission and of its correlation with cervix cancer. Our findings evidenced that HPV infection is frequent in women aged 18-46 years in Sardinia and particularly that 16 and 18 HPV genotypes are detectable in more than 40% of the infected women. The proportion of women informed about HPV issues is sufficient to guarantee an aware approach to HPV vaccination.

Decreased p21 expression in HPV-18 positive cervical carcinomas

The aim of this study was to investigate the relationship between different human papillomavirus (HPV) genotypes and the expression of p53, p21 and p27 in cervical carcinomas. A total of 103 cases of cervical carcinomas were assayed for expression of p53, p21 and p27 by immunohistochemistry. HPV typing was carried out by two polymerase chain reaction-based methods. Overall, HPV prevalence was 97.1% among the cervical carcinomas in this study. HPV-16 was detected in 66% of the tumors, HPV-18 in 7.8%, HPV-16/18 in 7.8% and other HPV types in 15.5%. The expression of p53 and p27 was not related to HPV genotype. However, in the HPV-18 positive cervical carcinomas, expression of p21 was significantly decreased or completely absent (P = 0.019). Our results indicated that down-regulation of p21 was strongly associated with HPV-18 positive cervical carcinomas. The significantly lower expression of p21 protein in HPV-18 positive samples compared to HPV-18 negative cervical carcinomas supports the hypothesis that inactivation and degradation of p21 proteins by HPV-18 E7 may play an important role in the carcinogenesis of HPV-18 positive cervical neoplasia.

Molecular variants of HPV-16 associated with cervical cancer in Indian population

Human papilloma virus is a causative factor in the etiology of cervical cancer with HPV16 being the most prevalent genotype associated with it. Intratype variations in oncogenic E6/E7 and capsid L1 proteins of HPV 16 besides being of phylogenetic importance, are associated with risk of viral persistence and progression. The objective of this multicentric study was to identify HPV-16 E6, E7 and L1 variants prevalent in India and their possible biological effects. Squamous cell cervical cancer biopsies were collected from 6 centres in India and examined for the presence of HPV 16. Variants of HPV-16 were characterized by full length sequence analysis of L1, E6 and E7 genes in 412 samples. Similar distribution of the variants was seen from the different centres/regions, with the European variant E350G being the most prevalent (58%), followed by American Asian variant (11.4%). Fifty six changes were seen in E6 region, 31 being nonsynonymous. The most frequent being L83V (72.3%), Q14H (13.1%) and H78Y (12.1%). Twenty-nine alterations were seen in E7 region, with 12 being nonsynonymous. The most frequent being F57V (9%). L1 region showed 204 changes, of which 67 were nonsynonymous. The most frequent being 448insS (100%), and 465delD (100%), H228D (94%), T292A (85%). The identified variants some new and some already reported can disrupt pentamer formation, transcriptional regulation of the virus, L1 protein interface interaction, B and T cell epitopes, p53 degradation, and thus their distribution is important for development of HPV diagnostics, vaccine, and for therapeutic purpose.

Entire genome characterization of human papillomavirus type 16 from infected Thai women with different cytological findings

Global prevalence of human papillomavirus type 16 (HPV16) exceeds that of other types. This project has been aimed at attaining basic molecular knowledge of HPV16 by sequencing the whole genome of HPV16 isolated from Thai women at various clinical stages of disease progression. Our group analyzed seven samples of HPV16 in infected women ranging from normal to cervical cancer and discovered two critical non-synonymous changes within the coding region converting the E2-219P prototype to E2-219T in cervical cancer and the L2-269S prototype to L2-269D in CIN III, respectively. Phylogenetic analysis based on the whole genome with special emphasis on the genes E2, E6, L1, and L2 showed the Thai samples to be more closely related to the European than the non-European strains. The vaccine strain's L1 polypeptides showed close relationship to our samples. The results provide basic data for future research on cervical cancer pathogenesis and representative data of HPV16 genome in Southeast Asia.

The evaluation of human papillomavirus genotyping in cervical liquid-based cytology specimens; using the Roche Linear Array HPV genotyping assay

OBJECTIVE

To ascertain the usefulness of the Roche Linear Array human papillomavirus (HPV) genotyping assay for assessing HPV genotypes in liquid-based cytology (LBC) samples and to evaluate this methodology within a cytopathology laboratory. These tests are of importance as persistent infection with high-risk HPV genotypes is considered a causal factor in the development of cervical cancer.

METHODS

A total of 175 cervical LBC samples were tested using the Roche Linear Array HPV genotyping test. The suitability of the assay use in routine cytopathology laboratory was considered. HPV genotypes were matched to the cervical cytology results, which included negative, borderline nuclear abnormalities, mild, moderate and severe dyskaryosis.

RESULTS

The assay could be applied to screening samples with the combined result available at the reporting stage. There were no test failures. All samples used after cytological analysis had sufficient DNA for testing. The results were reproducible and easily read and there was concordance of results between biomedical scientists. The results of the assay showed co-infection with multiple HPV genotypes was common in both high-grade and low-grade cytology samples. The percentage of HPV+ samples in the normal cytology samples (although in this grouping the number of samples was low) was 37%. In the cytology samples reported as severe dyskaryosis the HPV genotypes most commonly found were HPV16 and HPV51.

CONCLUSION

The assay was able to detect multiple HPV infection with a wide range of genotypes in LBC samples sent for routine cytological analysis. It would be suitable for use in a cytopathology laboratory. The results of the assay show that the genotype profile has some variation from other geographical regions, and more work is needed to determine population prevalence, to ascertain the impact of the HPV vaccine, to evaluate test for cure and HPV triage management.

Epidemiological data of different human papillomavirus genotypes in cervical specimens of HIV-1-infected women without history of cervical pathology

AIM

To study the epidemiology of different human papillomavirus (HPV) genotypes in cervical samples of HIV-1-infected women with normal Papanicolau smears.

DESIGN

: Retrospective analysis of a prospective cohort.

PATIENTS AND METHODS

We selected HIV-1-infected women with 2 consecutive normal Papanicolau smears at baseline and at least 1 baseline and 1 follow-up cervical sample. HPV infection was assessed by second-generation hybrid capture (HC-2) and multiplex polymerase chain reaction (mPCR). HPV genotypes were determined by mPCR.

RESULTS

From a cohort of 139 women followed up to 4 years, 93 women meeting the inclusion criteria were analyzed. The mean period between samples was 20 months (range, 6-44 months). HPV baseline prevalence was 63% [59/93; 95% confidence interval (CI), 53% to 73%] using polymerase chain reaction and 41% (38/93; 95% CI, 31% to 51%) using HC-2, P = 0.007 (kappa, 0.45; P = 0.001). The most prevalent high oncogenic risk genotypes (HR-HPV) were HPV-16 (28%), HPV-33 (18%), HPV-52 (12%), HPV-58 (11%), and HPV-39 (11%). Infection with multiple HPV genotypes was detected in >40% of women. HPV infection persisted at follow-up in 86% (51/59; 95% CI, 77% to 95%) by polymerase chain reaction and 76% (29/38; 95% CI, 62% to 90%) by HC-2. HPV infection persisted in 55% of women with samples available beyond 3 years. The actuarial probabilities of clearance and incidence of HPV infection at 36 months were 16% and 45%, respectively.

CONCLUSIONS

HPV infection is highly prevalent and persistent among HIV-1-infected women with normal Papanicolau smears. HR-HPV genotypes other than HPV-16 (HPV-33, HPV-52) are frequently detected in HIV-infected women. mPCR provides better surveillance of HPV infection than HC-2 methods.

Risk factors for human papillomavirus exposure and co-factors for cervical cancer in Latin America and the Caribbean

The incidence of cervical cancer in Latin America and the Caribbean (LAC) is among the highest in the world. Because there are major demographic shifts happening in LAC countries (population growth, urbanization and ageing) cervical cancer incidence and mortality will likely continue to be a significant public health problem. Overall human papillomavirus (HPV) prevalence in the LAC general population has been found to be 2-fold higher than the average worldwide prevalence. The large HPV and cancer burden may be explained by the highly prevalent HPV variants of HPV types -16 and 18, which have an increased oncogenic potential. Given the major mode of transmission of genital HPV is sexual, certain, patterns of sexual behaviour (early age at first sexual intercourse, number of sexual partners and sexual behaviour of the partner) are associated with an increased risk of HPV genital acquisition. Although HPV infection is necessary for carcinogenesis, certain co-factors (high parity, long term use of oral contraceptives, smoking and co-infection with the human immunodeficiency virus (HIV)) help in the progression from infection to cancer. Many studies that have contributed to this evidence have been carried out in LAC and are reviewed and summarised in this article. Since HPV vaccines will likely take years to implement, and many more years to show impact on disease, cervical cancer screening programmes remain as the key intervention to control disease in LAC in the years to come.

Human papillomavirus 16 E6 variants differ in their dysregulation of human keratinocyte differentiation and apoptosis

L83V-related variants of human papillomavirus (HPV) 16 E6, exemplified by the Asian-American variant Q14H/H78Y/L83V, were shown to be more prevalent than E6 prototype in progressing lesions and cervical cancer. We evaluated functions relevant to carcinogenesis for the E6 variants L83V, R10/L83V and Q14H/H78Y/L83V as well as the prototype in a model of human normal immortalized keratinocytes (NIKS). All E6 expressing NIKS equally abrogated growth arrest and DNA damage responses. Organotypic cultures derived from these keratinocytes demonstrated hyperplasia and aberrantly expressed keratin 5 in the suprabasal compartment. In contrast, differentiation and induction of apoptosis varied. The E6 variant rafts expressed keratin 10 in nearly all suprabasal cells while the prototype raft showed keratin 10 staining in a subset of suprabasal cells only. In addition, E6 variant NIKS expressing R10G/L83V and Q14H/H78Y/L83V were more prone to undergo cell-detachment-induced apoptosis (anoikis) than NIKS expressing E6 prototype. The combined differentiation and apoptosis pattern of high-risk E6 variants, especially of Q14H/H78Y/L83V, may reflect a phenotype beneficial to carcinogenesis and viral life cycle.

Persistence of genital human papillomavirus infection in a long-term follow-up study of female university students

BACKGROUND

Little is known about the epidemiology of human papillomavirus (HPV) infections that persist for more than a few years.

METHODS

Four to 12 years after participation in a longitudinal study of incident HPV infection, a cohort of former university students returned for a follow-up visit that included HPV genotyping of cervical and vulvovaginal swab specimens and collection of colposcopy-directed biopsy specimens.

RESULTS

Of 147 women with HPV infection detected during their undergraduate years, 24 (16.3%) were positive for 1 or more of the same HPV types at follow-up. Overall, 27 (4.8%) of 567 type-specific HPV infections persisted, and DNA sequence analyses of a subset revealed that all were variant specific. Long-term HPV persistence was positively associated with frequent but sporadic detection of the same HPV type early during the course of the infection and with abnormal Pap tests and genital warts; it was negatively associated with marriage and was not associated with the number of intercurrent sex partners.

CONCLUSIONS

HPV variant and behavioral risk factor analyses indicated that long-term detection of the same HPV type was more consistent with viral persistence than with reinfection. Although long-term persistence was not common, it was associated with detection of HPV-related pathologies.

Interaction between polymorphisms of the human leukocyte antigen and HPV-16 variants on the risk of invasive cervical cancer

Background

Persistent infection with oncogenic types of human papillomavirus (HPV) is the major risk factor for invasive cervical cancer (ICC), and non-European variants of HPV-16 are associated with an increased risk of persistence and ICC. HLA class II polymorphisms are also associated with genetic susceptibility to ICC. Our aim is to verify if these associations are influenced by HPV-16 variability.

Methods

We characterized HPV-16 variants by PCR in 107 ICC cases, which were typed for HLA-DQA1, DRB1 and DQB1 genes and compared to 257 controls. We measured the magnitude of associations by logistic regression analysis.

Results

European (E), Asian-American (AA) and African (Af) variants were identified. Here we show that inverse association between DQB1*05 (adjusted odds ratio [OR] = 0.66; 95% confidence interval [CI]: 0.39–1.12]) and HPV-16 positive ICC in our previous report was mostly attributable to AA variant carriers (OR = 0.27; 95%CI: 0.10–0.75). We observed similar proportions of HLA DRB1*1302 carriers in E-P positive cases and controls, but interestingly, this allele was not found in AA cases (p = 0.03, Fisher exact test). A positive association with DRB1*15 was observed in both groups of women harboring either E (OR = 2.99; 95% CI: 1.13–7.86) or AA variants (OR = 2.34; 95% CI: 1.00–5.46). There was an inverse association between DRB1*04 and ICC among women with HPV-16 carrying the 350T [83L] single nucleotide polymorphism in the E6 gene (OR = 0.27; 95% CI: 0.08–0.96). An inverse association between DQB1*05 and cases carrying 350G (83V) variants was also found (OR = 0.37; 95% CI: 0.15–0.89).

Conclusion

Our results suggest that the association between HLA polymorphism and risk of ICC might be influenced by the distribution of HPV-16 variants.

Does pretreatment HPV viral load correlate with prognosis in patients with early stage cervical carcinoma?

OBJECTIVE

Recent data suggest that pretreatment HPV (Human papillomavirus) viral load is useful to predict the severity of intraepithelial lesions of the uterine cervix and formulate a treatment plan. However, the relationship between initial HPV viral load and prognosis of cervical cancer patients has not yet been clearly defined. The objective of this study was to determine whether HPV viral load has prognostic significance in patients with early stage cervical carcinoma treated by surgery.

METHODS

A retrospective review of all patients with early stage cervical carcinoma who underwent radical hysterectomy and pelvic lymphadenectomy at our institution from August 2003 to December 2007 was conducted. Patients were included only if they had pretreatment Hybrid Capture II test for HPV DNA detection.

RESULTS

We identified 34 patients who met the inclusion criteria. Two groups were identified: patients who had low HPV viral load (</=100 RLU) versus those who had high viral load (>100 RLU). There were no differences in age, FIGO stage, histology, pathologic risk factors - tumor size, deep stromal invasion, lymph-vascular space invasion, parametrial extensions, vaginal margin involvement, and lymph node metastasis - and adjuvant CCRT. There was no significant difference of disease-free survival regard to pretreatment HPV viral load (p=0.7756).

CONCLUSION

In our study, survival was not significantly different between early stage cervical cancer patients who had low and high pretreatment HPV viral load. It seems that pretreatment HPV viral load may not be of help to predict disease prognosis.

Mutation in the immunodominant epitope of the HPV16 E7 oncoprotein as a mechanism of tumor escape

Infection with high-risk types of human papillomavirus (HPV) can cause the development of malignant tumors. To study mechanisms responsible for immune escape of tumor cells infected with HPV16, we previously used mouse oncogenic TC-1 cells producing HPV16 E6 and E7 oncoproteins to derive TC-1 clones resistant to immunization against E7. We have found immunoresistance of the clones to correlate with the point mutation in the E7 oncogene, which resulted in the N53S substitution in the immunodominant epitope RAHYNIVTF (aa 49-57). Here, we have shown that this mutation reduced stabilization of H-2D(b) molecules on RMA-S cells and eliminated immunogenicity of E7. The resistance of TC-1 clones was E7-specific as immunization against E6 inhibited tumor growth. Transduction of the TC-1/F9 clone carrying the mutated epitope with the wild-type E7 gene restored susceptibility to immunization against E7. Our results suggest that mutagenesis of tumor antigens can lead to the escape of malignant cells and should be considered in the development and evaluation of cancer immunotherapy.

Isolation and functional analysis of five HPVE6 variants with respect to p53 degradation

Persistent infection with high risk human papillomavirus is a necessary risk factor in the etiology of invasive cervical carcinoma. With regard to molecular details, the best studied types are HPV16 and HPV18 which are found in 70% of cervical cancer worldwide, however factors associated with the progression of individual cervical intraepithelial neoplasias into cancer are still poorly understood. Intratype amino acid variations in the immortalizing and transforming early proteins E6 and E7 were described to be associated with progressive disease and linked to increased viral persistence or progression. One of the key actions of high risk HPVE6 proteins is the inhibition of the function of p53, a tumor suppressor protein, by enhancing its degradation through the ubiquitin pathway. In this study, variants of five HPV type E6 proteins (HPV35, 53, 56, 66, and 70) isolated from patient materials are described and functional analysis of them were done with respect to p53 degradation. Interestingly the E6 protein of HPV type 53, which has no consistent risk classification in the literature showed the highest variability in our study. The analysis of all variants revealed no differences with regard to the degradation ability for p53 compared to the prototype E6 proteins, suggesting that the variants tested revealed no altered functions related to the carcinogenicity of the respective HPV types. It therefore seems more likely that variations in the E6 gene sequence may allow evasion from the hosts immune system, supporting increased viral persistence.

Baseline assessment of prevalence and geographical distribution of HPV types in Chile using self-collected vaginal samples

BACKGROUND

Chile has broad variations in weather, economics and population from the far desert north (Region 1) to the cold, icy south (Region 12). A home-based self-collected vaginal sampling was nested in the 2003 Chilean population-based health survey in order to explore the possibility of a type-specific geographical variation for human papillomavirus

METHODS

The population was a national probability sample of people 17 years of age and over. Consenting women provided self-collected cervicovaginal swabs in universal collection media (UCM). DNA was extracted and typed to 37 HPV genotypes using PGMY consensus PCR and line blot assay. Weighted prevalence rates and adjusted OR were calculated.

RESULTS

Of the 1,883 women participating in the health survey, 1,219 (64.7%) provided a cervicovaginal sample and in 1,110 (56.2% of participants and 66.5% of those eligible) the samples were adequate for analysis. Refusal rate was 16.9%. HPV prevalence was 29.2% (15.1% high-risk HPV and 14.1% low-risk HPV). Predominant high-risk types were HPV 16, 52, 51, 56 and 58. Predominant low-risk HPVs were HPV 84, CP6108, 62, 53 and 61. High-risk and low-risk HPV rates were inversely correlated between the regions. High-risk HPV prevalence was highest among the youngest women, whereas low-risk HPV increased slightly with age.

CONCLUSION

Self-obtained vaginal sampling is adequate for monitoring HPV in the community, for identifying high-risk areas, and for surveying the long term impact of interventions.

Prevalence of high-risk human papillomavirus types in Mexican women with cervical intraepithelial neoplasia and invasive carcinoma

Background

Prevalence of high risk (HR) human papillomavirus (HPV) types in the states of San Luis Potosí (SLP) and Guanajuato (Gto), Mexico, was determined by restriction fragment length-polymorphism (RFLP) analysis on the E6 ~250 bp (E6-250) HR-HPV products amplified from cervical scrapings of 442 women with cervical intraepithelial neoplasia and invasive carcinoma (280 from SLP and 192 from Gto). Fresh cervical scrapings for HPV detection and typing were obtained from all of them and cytological and/or histological diagnoses were performed on 383.

Results

Low grade intraepithelial squamous lesions (LSIL) were diagnosed in 280 cases (73.1%), high grade intraepithelial squamous lesions (HSIL) in 64 cases (16.7%) and invasive carcinoma in 39 cases (10.2%). In the 437 cervical scrapings containing amplifiable DNA, only four (0.9%) were not infected by HPV, whereas 402 (92.0%) were infected HR-HPV and 31 (7.1%) by low-risk HPV. RFLP analysis of the amplifiable samples identified infections by one HR-HPV type in 71.4%, by two types in 25.9% and by three types in 2.7%. The overall prevalence of HR-HPV types was, in descending order: 16 (53.4%) > 31 (15.6%) > 18 (8.9%) > 35 (5.6) > 52 (5.4%) > 33 (1.2%) > 58 (0.7%) = unidentified types (0.7%); in double infections (type 58 absent in Gto) it was 16 (88.5%) > 31 (57.7%) > 35 (19.2%) > 18 (16.3%) = 52 (16.3%) > 33 (2.8%) = 58 (2.8%) > unidentified types (1.0%); in triple infections (types 33 and 58 absent in both states) it was 16 (100.0%) > 35 (54.5%) > 31 (45.5%) = 52 (45.5%) > 18 (27.3%). Overall frequency of cervical lesions was LSIL (73.1%) > HSIL (16.7%) > invasive cancer (10.2%). The ratio of single to multiple infections was inversely proportional to the severity of the lesions: 2.46 for LSIL, 2.37 for HSIL and 2.15 for invasive cancer. The frequency of HR-HPV types in HSIL and invasive cancer lesions was 16 (55.0%) > 31 (18.6%) > 35 (7.9%) > 52 (7.1%) > 18 (4.3%) > unidentified types (3.6%) > 33 (2.9%) > 58 (0.7%).

Conclusion

Ninety percent of the women included in this study were infected by HR-HPV, with a prevalence 1.14 higher in Gto. All seven HR-HPV types identifiable with the PCR-RFLP method used circulate in SLP and Gto, and were diagnosed in 99.3% of the cases. Seventy-one percent of HR-HPV infections were due to a single type, 25.9% were double and 2.7% were triple. Overall frequency of lesions was LSIL (73.1%) > HSIL (16.7%) > invasive cancer (10.2%), and the ratio of single to multiple infections was inversely proportional to severity of the lesions: 2.46 for LSIL, 2.37 for HSIL and 2.15 for invasive cancer. The frequency of HR-HPV types found in HSIL and invasive cancer was 16 (55.0%) > 31 (18.6%) > 35 (7.9%) > 52 (7.1%) > 18 (4.3%) > unidentified types (3.6%) > 33 (2.9%) > 58 (0.7%). Since the three predominant types (16, 31 and 18) cause 77.9% of the HR-HPV infections and immunization against type 16 prevents type 31 infections, in this region the efficacy of the prophylactic vaccine against types 16 and 18 would be close to 80%.

Human papillomavirus type 16 variant analysis of E6, E7, and L1 genes and long control region in biopsy samples from cervical cancer patients in north India

High-risk human papillomaviruses (HPVs), particularly HPV types 16 and 18 (HPV-16 and HPV-18, respectively), play a cardinal role in the etiology of cervical cancer. The most prevalent type, HPV-16, shows intratypic sequence variants that are known to differ in oncogenic potential and geographic distribution. This study was designed to analyze sequence variations in E6, E7, and L1 genes and the LCR (for long control region) of HPV-16 in cervical cancer patients to identify the most prevalent and novel HPV-16 variants and to correlate them with the severity of the disease. Cervical biopsies from 60 HPV-16-positive cancer cases were analyzed by PCR and DNA sequencing. The most frequently observed variations were T350G (100%) in E6, T789C (87.5%) in E7, A6695C (54.5%) in L1, and G7521A (91.1%) in the LCR. In addition, only one novel variant (T527A) in E6 and four new variants each in L1 (A6667C, A6691G, C6906T, and A6924C) and in the LCR (C13T, A7636C, C7678T, and G7799A) were identified. While E7 was found to be highly conserved, the variant 350G of E6 was the most prevalent in all of the histopathological grades. The majority of LCR variants were found at the YY1 transcription factor binding sites. Interestingly, a complete absence of the Asian lineage and a high prevalence of European lineages in E6, E7, L1, and the LCR (85, 86.7, 67.7, and 63.3%, respectively) indicate a possible epidemiological linkage between Europe and India with regard to the dissemination of HPV-16 infections in India.

Human papillomavirus (HPV) in atypical squamous cervical cytology: the Invader HPV test as a new screening assay

In surveillance for cervical neoplasia, a diagnosis of cytologically atypical squamous cells of undetermined significance (ASCUS) presents a significant clinical issue, often dependent on testing for high-risk (HR) human papillomavirus (HPV) for the triage of patients. HPV type 16 now appears to be a critical concern in the follow-up of patients with ASCUS. The Invader HPV (Inv2) test, by Third Wave Technologies, Inc., is a recently developed analyte-specific reagent assay that uses probe sets for the detection of 14 HR HPV subtypes. These probe sets are A5/A6 (HPV types 51, 56, and 66), A7 (HPV types 18, 39, 45, 59, and 68), and A9 (HPV types 16, 31, 33, 35, 52, and 58). This report describes the performance characteristics of the Inv2 test in the screening of ASCUS cervical cytology specimens and correlates the results of the Inv2 test with those of the Hybrid Capture II HPV (HC2) test by Digene. The linear array HPV genotyping test (Roche Molecular Systems) was used as a reference method for the testing of samples with discordant results. Ninety-four Pap smear samples with a cytological diagnosis of ASCUS and 39 samples with a negative diagnosis were tested. The results of the Inv2 test demonstrated a good (86.6%) concordance with those of the HC2 test, with an overall sensitivity and specificity of 96% for the Inv2 test. Additionally, the Inv2 assay, which offers high-throughput, semiautomated DNA extraction, allows the subgrouping of HPV types by differential probe sets, could provide a useful test for screening for HPV, and has the potential to provide an improved means of risk stratification and the selection of patients for further HPV subtyping.

Modeling human papillomavirus and cervical cancer in the United States for analyses of screening and vaccination

Background

To provide quantitative insight into current U.S. policy choices for cervical cancer prevention, we developed a model of human papillomavirus (HPV) and cervical cancer, explicitly incorporating uncertainty about the natural history of disease.

Methods

We developed a stochastic microsimulation of cervical cancer that distinguishes different HPV types by their incidence, clearance, persistence, and progression. Input parameter sets were sampled randomly from uniform distributions, and simulations undertaken with each set. Through systematic reviews and formal data synthesis, we established multiple epidemiologic targets for model calibration, including age-specific prevalence of HPV by type, age-specific prevalence of cervical intraepithelial neoplasia (CIN), HPV type distribution within CIN and cancer, and age-specific cancer incidence. For each set of sampled input parameters, likelihood-based goodness-of-fit (GOF) scores were computed based on comparisons between model-predicted outcomes and calibration targets. Using 50 randomly resampled, good-fitting parameter sets, we assessed the external consistency and face validity of the model, comparing predicted screening outcomes to independent data. To illustrate the advantage of this approach in reflecting parameter uncertainty, we used the 50 sets to project the distribution of health outcomes in U.S. women under different cervical cancer prevention strategies.

Results

Approximately 200 good-fitting parameter sets were identified from 1,000,000 simulated sets. Modeled screening outcomes were externally consistent with results from multiple independent data sources. Based on 50 good-fitting parameter sets, the expected reductions in lifetime risk of cancer with annual or biennial screening were 76% (range across 50 sets: 69–82%) and 69% (60–77%), respectively. The reduction from vaccination alone was 75%, although it ranged from 60% to 88%, reflecting considerable parameter uncertainty about the natural history of type-specific HPV infection. The uncertainty surrounding the model-predicted reduction in cervical cancer incidence narrowed substantially when vaccination was combined with every-5-year screening, with a mean reduction of 89% and range of 83% to 95%.

Conclusion

We demonstrate an approach to parameterization, calibration and performance evaluation for a U.S. cervical cancer microsimulation model intended to provide qualitative and quantitative inputs into decisions that must be taken before long-term data on vaccination outcomes become available. This approach allows for a rigorous and comprehensive description of policy-relevant uncertainty about health outcomes under alternative cancer prevention strategies. The model provides a tool that can accommodate new information, and can be modified as needed, to iteratively assess the expected benefits, costs, and cost-effectiveness of different policies in the U.S.

Risk for high-grade cervical intraepithelial neoplasia associated with variants of human papillomavirus types 16 and 18

BACKGROUND

Although the variant lineages of human papillomavirus (HPV) types 16 and 18 are well established, their individual associations with high-grade cervical intraepithelial neoplasia (CIN) have not been extensively evaluated.

METHODS

Study subjects were women participating in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study who were positive for HPV16 or HPV18 at enrollment. These women were followed every 6 months for 2 years. Viral isolates from enrollment samples were characterized by DNA sequencing and classified as variant lineages.

RESULTS

Over a 2-year study period, CIN3 was histologically diagnosed in 291 of the 779 HPV16-positive women and 47 of the 275 HPV18-positive women. Among women without CIN2-3 at enrollment, the risk of subsequent CIN3 was 2.7-fold greater for those with HPV16 African-2 [95% confidence interval (95% CI), 1.0-7.0] and 3.1-fold greater for those with HPV16 Asian American (95% CI, 1.6-6.0), compared with European variants. Relative to infection with HPV18 African variants, the risk associating subsequent CIN3 was 3.8 (95% CI, 0.9-17.2) for infection with HPV18 European variants and 4.8 (95% CI, 1.0-23.6) for infection with HPV18 Asian American variants. Similar associations were observed when the 2-year prevalence of CIN3 was used as the end point. Further, for those with HPV16 European variants, the 2-year prevalence of CIN3 was higher in White women than in African American women (P = 0.01); this trend was reversed for those with HPV16 African-1 variants (P = 0.22). A similar pattern was present for infections with HPV18 European versus African variants.

CONCLUSIONS

The lineages of HPV16 and HPV18 variants are associated with differing risks for high-grade CIN.

High grade cervical lesions are caused preferentially by non-European variants of HPVs 16 and 18

The intratypic variability of HPVs 16 and 18 has been extensively studied and has been used as an important tool in epidemiological studies of viral transmission, persistence and progression to clinically relevant cervical lesions. Infections by non-European variants of HPVs 16 and 18 are associated with an increased risk for the development of high grade squamous intraepithelial lesions (HSIL). Our aim was to correlate the intratypic molecular variability of both HPV types and risk of persistent infection and lesion outcome in a cohort study conducted in Brazil. We characterized molecular variants of HPV types 16 and 18 by sequencing a fragment of the LCR, and of the E6 and L1 genes, for HPV-16 variants only. For both types, European variants composed the most prevalent and diverse group. Persistent infections with HPV-18 were associated with continuous detection of European variants. However, risk for simultaneous detection of HSIL and HPV DNA was higher in women harboring non-European variants of HPV-16. The same trend was observed with HSIL detected during follow-up. Our study confirms the association between non-European variants and risk of cervical neoplasia, and highlights the importance of their geographic distribution for cervical cancer risk assessment.

Association Between HLA-DRB1 polymorphism, high-risk HPV infection and cervical neoplasia in southern Chinese

Multiple determinants are involved in the progression of human papillomavirus (HPV)-infected cervical lesion to invasive cancer. Human leukocyte antigen (HLA) polymorphism seems to play a role. This study examined the association between HLA-DRB1 polymorphism, high-risk HPV infection, and the development of cervical neoplasia in southern Chinese. Three hundred and seventy women with cervical neoplasia (43 cervical intraepithelial neoplasia grade II, 154 grade III, and 173 invasive cancers) and 323 controls were recruited for HLA-DRB1 typing by a sequence-based approach. Cervical specimens were collected for HPV detection by a consensus primer-based polymerase chain reaction, and with the type of HPV identified by hybridization with type-specific oligonucleotide probes. A protective effect of HLA-DRB1*12 for cervical neoplasia was observed, and with stronger associations when subgroup analyses were carried out for patients infected with HPV16 and HPV58. The protective effect of HLA-DRB1*13 that had been reported from other populations was not observed. The data obtained in this study showed that HLA-DRB1*03 conferred a higher risk for HPV18-infected, but not for HPV16-, HPV52-, or HPV58-infected cervical lesions. Although, HPV52 was reported as uncommon worldwide, it was found to be the second most prevalent type in the southern Chinese population. However, no additional risk association was observed when subgroup analyses were performed for HPV52-infected patients. The current study shows that, among southern Chinese, the outcome of HPV-infected cervical lesions is associated with HLA-DRB1 polymorphism. These associations often vary with the type of HPV infection.

HPV16 E6 variants and HLA class II polymorphism among Chinese women with cervical cancer

Infection with human papillomavirus type 16 (HPV16) confers a high risk for the development of cervical cancer. Variants of this virus may interact differentially with host genetic factors, possibly affecting the disease pathogenesis. This study was designed to investigate the association between HPV16 E6 variants and human leukocyte antigen (HLA) polymorphism within a Chinese population. Peripheral blood from HPV16 positive Chinese women with cervical carcinoma, who had previously been tested for HPV16 E6 variants, was used for HLA class II typing. It was found that there was a significant positive association between DQB1*060101 allele and HPV16 As variant-positive cervical cancers (OR, 4.47; Pc=0.0018). A negative relationship was found between DRB1*150101-DQB1*0602 haplotype and decreased risk for HPV16 As variant-positive cervical cancers (OR=0.31; P=0.037). Similar tendency was observed for the haplotype DRB1*070101-DQB1*0201 with HPV16 As variant-positive cervical cancers (OR=0.16, P=0.024). Additionally, as for the HPV16 E6 prototype-positive cervical cancers, a significant positive association was found in DQB1*060101 allele (OR=5.95; P=0.002; Pc=0.036), and similar trends were observed for DQB1*030201 (OR=10.87, P<0.0001; Pc=0.0018), and DPB1*1301(OR=7.40, P=0.002; Pc=0.04). It was found that there was no significant association between DRB1-DQB1 haplotype and HPV16 prototype-positive cervical cancers. These data indicate that host genetic factors, such as HLA polymorphism, may determine the potential oncogenicity of the HPV16 E6 variant. The results suggest that a specific match between E6 variant proteins and HLA class II alleles may contribute to HPV16-related cervical carcinogenesis in a certain Chinese population.

Activities of human papillomavirus 16 E6 natural variants in human keratinocytes

Genetic variations in the E6 oncogene have been associated with different risk for cancer progression. In the present study, the functional significance of human papillomavirus (HPV) polymorphism in the E6 oncogene was investigated. Ten HPV16 E6 variants containing amino acid substitutions in the N-terminal region of E6 were evaluated for different biological and biochemical activities in human keratinocytes, the target cells for HPV infection. Western blot analyses of primary foreskin human keratinocytes or immortalized human keratinocytes, stably transduced with the E6 variants, revealed reduced p53 and Bax levels in all E6 expressing cultures. The reduction induced by most E6 proteins was at similar levels and comparable to the reduction induced by the E6 prototype. The ability of the proteins to induce serum/calcium-differentiation resistant colonies in primary keratinocytes was more variable. Overall activities of the variants ranged between 0.24- and 2.18-fold of the E6 prototype activity. The I27R/L83V variant showed the lowest activity whereas the R8Q variant showed the highest activity. The L83V polymorphism previously associated with risk for cancer progression in some populations, showed significant activity, comparable to that of the E6 prototype, in reducing p53 and Bax levels. Furthermore, this variant showed enhancement in the ability to induce colonies resistant to serum/calcium-triggered differentiation, however, the difference from the prototype was not statistically significant. This, and augmentation of other described functions might result in differences in L83V pathogenicity.

Molecular variants of human papillomavirus type 16 and risk for cervical neoplasia in South Africa

Non-European variants of human papillomavirus (HPV) type 16 are generally associated with a greater risk of cervical neoplasia than European prototype variants. We investigated whether this association would persist in a population in which non-European HPV 16 variants were more common. We sequenced HPV 16 isolates in cervical samples collected from 93 Black South African women enrolled in a cervical cancer screening study and examined associations between cervical neoplasia identified though colposcopy with cervical biopsy and the specific HPV 16 variant identified. The European prototype variant (EP) was the most commonly identified variant in this population (47% of all isolates), but African variants (Af-1 and Af-2) were also quite common (41% of all isolates). In contrast to previous studies, we found no evidence that non-European variants were associated with an increased risk of neoplasia. Rather, most of the HPV 16-associated cancers were found in association with EP (71% of 14 cases). In this setting where African HPV 16 variants were common, no increased risk for cervical neoplasia was found among women with these variants compared with other HPV 16 variants.

Longitudinal study of patients after surgical treatment for cervical lesions: detection of HPV DNA and prevalence of HPV-specific antibodies

The principal aims of this study were to test whether persistence of human papillomavirus (HPV) DNA is predictive of recurrent disease in women after surgical treatment for cervical lesions, to distinguish between persistent and newly acquired HPV infection, and to observe the effect of surgical treatment on levels of HPV-specific antibodies. A group of 198 patients surgically treated for low-grade and high-grade squamous intraepithelial lesions and 35 age-matched controls were monitored for 18 months at 6-month intervals. The presence of HPV DNA in cervical smears was detected by means of consensus polymerase chain reaction, and serum levels of HPV-specific antibodies to HPV types 16, 18, 31, 33, and 45 were measured. In ten patients positive for HPV type 16 in consecutive samples, the HPV 16 variants were identified using a polymerase chain reaction specific for the long control region. Data regarding demographics, risk factors for cervical cancer, and risks related to HPV exposure were collected through a patient questionnaire. Subjects persistently positive for HPV DNA were more likely to present with cytological and/or colposcopical abnormalities. A higher reactivity to HPV-specific antibodies was observed in these women at the 18-month follow-up visit. All ten patients with HPV 16 infection detected in consecutive samples showed persistence of either the same prototype or the same variant during the follow-up period. Risky sexual behavior and smoking were more common in patients than in controls. Persistent HPV infection as demonstrated by both HPV DNA detection and antibody detection appears to be a risk factor for the recurrence of pathological findings in women after surgery. An individually based approach to surgical treatment is an important factor in the outcome of disease at follow-up.

HPV16 variants in squamous intraepithelial lesions in human immunodeficiency virus-negative and -positive Brazilian women

Emerging evidence supports the role of human papillomavirus (HPV) intratype variations in the development of cervical lesions in immunocompetent women, but few studies investigated HPV16 variants in human immunodeficiency virus (HIV)-positive women. This is the first study in Brazil evaluating HPV16 variants in women with (n = 19) and without (n = 22) HIV infection, as well as cervical lesions. Although non-European variants presented an almost 3-fold increase (13.6% vs. 36.8%) among HIV-positive women, associations between HPV16 variants and HIV infection did not reach statistical significance (Fisher's exact test, p = 0.15). No associations were found between non-European variants and HSIL (Fisher's exact test, p = 0.41), although a significant association was observed between European variants and HSIL among HIV-negative women (Fisher's exact test, p = 0.01). In conclusion, in HIV-negative women the HPV16 European variants seem to influence the occurrence of HSIL, whereas in HIV-positive women, similar roles are atributted to both variants.

Immune responses to human papillomavirus

The immune system uses innate and adaptive immunity to recognize and combat foreign agents that invade the body, but these methods are sometimes ineffective against human papillomavirus (HPV). HPV has several mechanisms for avoiding the immune system. HPV infects, and multiplies in keratinocytes, which are distant from immune centers and have a naturally short lifespan. The naturally short life cycle of the keratinocyte circumvents the need for the virus to destroy the cell, which would trigger inflammation and immune response. In addition, HPV downregulates the expression of interferon genes. Despite viral immune evasion, the immune system effectively repels most HPV infections, and is associated with strong localized cell mediated immune responses. New prophylactic L1 virus-like protein vaccines for HPV 16 and 18 and HPV 6, 11, 16, and 18 are in phase 3 trials. Available data suggests that these vaccines are safe, produce high levels of antibodies, and are effective at preventing HPV infection.

Human Papillomavirus Type 16 and 18 Variants: Race-Related Distribution and Persistence

BACKGROUND

Analogous to the geographic distribution of variants of human papillomavirus (HPV) types, the distribution and persistence of these variants among infected individuals may be related to the racial composition of a population living in one geographic region.

METHODS

We studied 1114 women in the United States participating in the Atypical Squamous Cells of Undetermined Significance/Low-Grade Squamous Intraepithelial Lesion Triage Study who were positive for HPV16 and/or HPV18 at enrollment. Race was self-reported. HPV samples were characterized by sequencing the E6 gene and part of the long control region and classified as variants according to established lineages. Subjects were examined for HPV every 6 months for 2 years. All statistical tests were two-sided.

RESULTS

HPV18 African variants were predominant in the 97 HPV18-infected African American women (i.e., 62 women or 63.9%, 95% confidence interval [CI] = 53.5% to 73.4%), and European variants were common in the 168 HPV18-infected white women (i.e., 91 women or 54.2%, 95% CI = 46.3% to 61.9%). HPV16 African variants accounted for 43 (26.5%, 95% CI = 19.9% to 34.0%) of the infections in the 162 HPV16-infected African American women but for only 25 (4.3%, 95% CI = 2.8% to 6.3%) in the 584 HPV16-infected white women. The likelihood of remaining HPV18 positive was statistically significantly higher in white women infected with European than in white women infected with African variants (P = .04); the reverse was observed in African American women (P = .03). A similar pattern was observed for persistence of HPV16 variants, with the likelihood of remaining positive being higher for white women, but lower for African American women, infected with an European variant than with an African variant (P = .03 and P = .16, respectively).

CONCLUSIONS

Variants of HPV16 and HPV18 appear to persist longer in a host whose race indicates an ancestral geographic distribution that was once shared with that of the variant-i.e., European variants persist longer in white women, and African variants persist longer in African American women.

Human papillomavirus type 16 molecular variants in Guarani Indian women from Misiones, Argentina

OBJECTIVE

To identify human papillomavirus type 16 (HPV16) E6 and L1 molecular variants infecting Guarani Indian women settled in Misiones, Argentina, a region with a high prevalence of cervical cancer. Some intratypic molecular variants of HPV16 have been associated with greater oncogenic risk, but their implication in the etiology of cervical cancer is still uncertain.

METHODS

Seventy HPV16 positive cervical samples from Guarani Indian women settled in two different areas of Misiones, Argentina, (34 from the northern area and 36 from the central area), were analyzed. Thirty-seven had normal cytology, 18 had a low-grade squamous intraepithelial lesion (LGSIL), and 15 a high-grade squamous intraepithelial lesion (HGSIL). HPV16 E6 and L1 molecular variants were identified by PCR, followed by dot blot hybridization with 23 and 12 biotinylated oligonucleotide probes, respectively.

RESULTS

The frequency of HPV16 variants over the Guarani population was 51% EP (European prototype), 32% E-350G, 9% Af1-a (African 1), 4% E-6862C, 3% Af2-a, and 1% AA-a (Asian-American). The distribution of variants was not homogeneous in the two areas under analysis, with the northern area being more diverse showing 74% of European variants, while the central area presented exclusively E variants. No statistically significant association was found between any particular variant and grade of cervical lesion.

CONCLUSION

This study reports for the first time HPV16 E6 and L1 molecular variants infecting women from an aboriginal community inhabiting a rainforest region of South America. The presence of E class variants could be attributed primarily to contacts with the Spanish conquerors, and Af variants from African slaves introduced later in the South American continent.

Epidemiological and functional implications of molecular variants of human papillomavirus

Human papillomavirus genomes are classified into molecular variants when they present more than 98% of similarity to the prototype sequence within the L1 gene. Comparative nucleotide sequence analyses of these viruses have elucidated some features of their phylogenetic relationship. In addition, human papillomavirus intratype variability has also been used as an important tool in epidemiological studies of viral transmission, persistence and progression to clinically relevant cervical lesions. Until the present, little has been published concerning the functional significance of molecular variants. It has been shown that nucleotide variability within the long control region leads to differences in the binding affinity of some cellular transcriptional factors and to the enhancement of the expression of E6 and E7 oncogenes. Furthermore, in vivo and in vitro studies revealed differences in E6 and E7 biochemical and biological properties among molecular variants. Nevertheless, further correlation with additional functional information is needed to evaluate the significance of genome intratypic variability. These results are also important for the development of vaccines and to determine the extent to which immunization with L1 virus-like particles of one variant could induce antibodies that cross-neutralize other variants.

HPV16 E6 natural variants exhibit different activities in functional assays relevant to the carcinogenic potential of E6

Genetic studies have revealed natural amino acid variations within the human papillomavirus (HPV) type 16 E6 oncoprotein. To address the functional significance of E6 polymorphisms, 10 HPV16 E6 variants isolated from cervical lesions of Swedish women were evaluated for their activities in different in vitro and in vivo assays relevant to the carcinogenic potential of E6. Small differences between E6 prototype and variants, and among variants, were observed in transient expression assays that assessed p53 degradation, Bax degradation, and inhibition of p53 transactivation. More variable levels of activities were exhibited by the E6 proteins in assays that evaluated binding to the E6-binding protein (E6BP) or the human discs large protein (hDlg). The E6 prototype expressed moderate to high activity in the above assays. The L83V polymorphism, previously associated with risk for cancer progression in some populations, expressed similar levels of activity as that of the E6 prototype in most functional assays. On the other hand, L83V displayed more efficient degradation of Bax and binding to E6BP, but lower binding to hDlg. Results of this study indicate that naturally occurring amino acid variations in HPV16 E6 can alter activities of the protein important for its carcinogenic potential.

Smokers at Higher Risk for Undetected Antibody for Oncogenic Human Papillomavirus Type 16 Infection

OBJECTIVE

To determine the association between tobacco smoking and serologic evidence of human papillomavirus type 16 (HPV16)-specific antibodies among HPV16 DNA-positive women.

DESIGN, SETTING, AND PARTICIPANTS

Baseline health history, physical examination, and laboratory data for 205 HPV16 DNA-positive women with no prior cytologic evidence of squamous intraepithelial lesions who were enrolled subsequently in a randomized clinical trial.

MAIN OUTCOME MEASURE

HPV16-L1 antibody (anti-HPV16 antibody) detected from serum using RIA or ELISA.

RESULTS

Eighty-seven percent (179 of 205) of women tested positive for HPV16 DNA using cervicovaginal swabs or lavage specimens, and 26 women showed similar results using swab specimens of external genitalia alone. HPV16-infected women who reported increasingly greater levels of daily cigarette smoking were less likely to test positive for anti-HPV16 antibodies than nonsmoking women (P = 0.02). Smokers were twice as likely as nonsmokers to test negative for anti-HPV16 antibodies, even after controlling for the effects of other covariates in the analyses (adjusted odds ratio, 0.5; 95% confidence limits, 0.2-0.9). Although Papanicolaou test findings and smoking characteristics were poorly correlated (r(2) = 0.01), women who showed atypical cells of unknown significance or squamous intraepithelial lesion were twice as likely to test anti-HPV16 antibody positive as women who showed normal Papanicolaou tests (adjusted odds ratio, 2.0; 95% confidence limits, 1.1-3.7).

CONCLUSION

These data suggest that smoking may influence the long-term risk for cancer by perturbing early immune responses to the virus and may increase the likelihood of persistent infection. Patient education messages should alert women to this additional risk of smoking. A clinical trial of smoking cessation should be explored as a therapeutic intervention for primary HPV16 infection.

Genome variation of human papillomavirus types: phylogenetic and medical implications

Human papillomaviruses (HPVs) are described as "types" based on their genome sequences and identified by a number. For example, HPV-6 is associated with genital warts, and HPV-16 with anogenital cancers. The genomes of many HPV types have been reisolated, sequenced and compared to reference "prototypes" countless times by laboratories throughout the world. It was found that each HPV type occurs in the form of "variants", identified by about 2% nucleotide differences in most genes and 5% in less conserved regions. Less than 100 variants of any HPV type have been detected, a scenario that is very different from the quasi-species formed by many RNA viruses. The variants of each HPV type form phylogenetic trees, and variants from specific branches are often unique to specific ethnic groups. Immigrant populations contain, depending on their respective ethnic origins, mixtures of variants. The absence of HPV genomes intermediate to specific types show that all HPV types existed already when humans became a species. Consequently, humans had always suffered from lesions like anogenital cancer, genital warts and common warts. A growing number of epidemiological, etiological and molecular data suggest that variants of the same HPV type are biologically distinct and may confer differential pathogenic risks. Since the distribution of some variants of HPV-16 and 18 correlates with the distribution of human populations that have an increased risk to develop anogenital cancer, the study of HPV type variation may point to one of the reasons for the higher incidence rates of these lesions in specific cohorts.

Incident High-Grade Squamous Intraepithelial Lesions in Senegalese Women With and Without Human Immunodeficiency Virus Type 1 (HIV-1) and HIV-2

BACKGROUND

Women infected with human immunodeficiency virus type 1 (HIV-1) and -2 may be at higher risk of developing cervical cancer than uninfected women. We assessed the relationships among human papillomavirus (HPV) types and persistence, HIV-1 and/or HIV-2 infection, and the development of high-grade cervical squamous intraepithelial lesions (HSILs) in a prospective study.

METHODS

We studied 627 women with and without HIV-1 and/or HIV-2 infection and high-risk HPV infection in Senegal, West Africa, who were assessed every 4 months for HSIL and HPV DNA over a mean follow-up of 2.2 years. Cox regression modeling was used to assess risks associated with development of HSIL.

RESULTS

During follow-up, 71 (11%) of 627 women developed HSIL as detected by cytology. HIV-infected women with high-risk HPV types were at greatest risk for development of HSIL. In multivariable modeling, infection with oncogenic HPV types--both persistent (hazard ratio [HR] = 47.1, 95% confidence interval [CI] = 16.3 to 136) and transient (HR = 14.0, 95% CI = 3.7 to 54)--was strongly associated with HSIL risk. In univariate analyses, HIV-positive women infected with HIV-2 were less likely to develop HSIL (HR = 0.3, 95% CI = 0.1 to 0.9) than HIV-positive women infected with HIV-1. HIV-positive women with CD4+ cell counts between 200 and 500 cells per microliter (HR = 2.2, 95% CI = 0.8 to 6.3) or fewer than 200 cells per milliliter (HR = 5.5, 95% CI = 2.0 to 15.2) were at greater risk of HSIL than HIV-positive women with CD4 counts of more than 500 cells per milliliter. High plasma HIV RNA levels were associated with increased HSIL risk (HR for each order of magnitude increase in the level of plasma HIV RNA = 1.4, 95% CI = 1.1 to 1.7; P = .005). After adjustment for HPV types and persistence, however, HIV type, plasma HIV RNA level, and CD4 count were no longer statistically significantly associated with increased risk of HSIL.

CONCLUSIONS

HIV-1 and HIV-2 are associated with increased risk for development of HSIL. This risk appears to be associated primarily with increased HPV persistence that may result from immunosuppression related to HIV-1 and/or HIV-2 infection.

Human papillomavirus genotype distribution in low-grade cervical lesions: comparison by geographic region and with cervical cancer

Low-grade squamous intraepithelial lesions (LSIL) associated with certain human papillomavirus (HPV) genotypes may preferentially progress to cervical cancer. HPV genotyping may thus have the potential to improve the effectiveness of screening programs and to reduce overtreatment. LSIL cases (n = 8,308) from 55 published studies were included in a meta-analysis. HPV genotype distribution was assessed by geographic region and in comparison with published data on cervical squamous cell carcinoma (SCC). HPV detection in LSIL was 80% in North America but less than 70% in other regions, most likely reflecting regional differences in LSIL diagnosis. Among 5,910 HPV-positive LSILs, HPV16 was the most common genotype (26.3%) followed by HPV31 (11.5%), HPV51 (10.6%), and HPV53 (10.2%). HPV-positive LSILs from Africa were 2-fold less likely to be infected with HPV16 than those in Europe, and HPV-positive LSILs from North America were more likely to be infected with HPV18 than those from Europe or South/Central America. Interpretation for rarer genotypes was hampered by variation in HPV testing methodology. SCC/LSIL prevalence ratios indicated that HPV16 was 2-fold and HPV18 was 1.5-fold more common in SCC than in HPV-positive LSIL, thus appearing more likely to progress than other high-risk genotypes (SCC/LSIL prevalence ratios between 0.05 and 0.85). HPV53 and HPV66 showed SCC/LSIL ratios of 0.02 and 0.01, respectively. HPV genotype distribution in LSIL differs from that in cervical cancer, highlighting the importance of HPV genotype in the risk of progression from LSIL to malignancy. Some regional differences in the relative importance of HPV genotypes in LSIL were noted.

Human papillomavirus (HPV) DNA detection in self-collected urine

OBJECTIVE

Non-invasive sampling of human genitals to identify high-risk individuals with subclinical oncogenic HPV infection remains a challenge. The study was designed to see if self-collected urine can be used as a simple, non-invasive sampling for screening HPV, particularly for screening/monitoring general population or young adolescents or infants, if they are to be immunized by HPV vaccines.

METHOD

Self-collected urine samples from 100 sexually unexposed college going girls and cervical scrapes from 104 normal healthy sexually active married women were used in this study. Additionally, a group of 55 women were recruited for collecting first urine and later scraped cervical cells to validate urine sampling by directly comparing HPV positivity between the two types of biological specimens. A dry 'paper smear' method for specimen collection and a simple single tube protocol was employed for PCR detection of HPV infection.

RESULTS

Out of 100 sexually inexperienced college going girls, only 6 (6%) were positive for HPV infection as revealed by L1 consensus primer and 4 (4%) of them were positive for HPV 16 but none was found positive for HPV 18 DNA. Out of 104 sexually active married women who were cytologically reported as negative by Pap test, 11 (10.5%) were found HPV positive and 7 (6.7%) of them had infection of high-risk HPV type 16. Both urine and later cervical scrapes from a group of 55 women collected as dry 'paper smear' showed perfect matching positivity for HPV between urine and cervical scrape.

CONCLUSIONS

The use of urine coupled with its dry collection as 'paper smear' facilitating their easy transport, storage and direct PCR detection of HPV DNA opens up an alternative non-invasive approach for population screening of HPV infection, at least in such cases as children and infants in whom invasive samples are difficult to obtain.

Interaction of host and viral risk factors for development of cervical carcinoma in situ

Infection by oncogenic human papillomavirus (HPV) is a necessary but not sufficient cause of cervical carcinoma. Several host genetic and viral factors have been reported to increase the risk of carcinoma development given an HPV infection. In our study, we have analysed the contribution of HPV 16 E6 sequence subtype and allelic variation at human leukocyte antigen (HLA) class II loci to the risk of developing cervical carcinoma in situ. Non-European-like HPV 16 E6 sequence subtypes were not found to be associated with an increased risk of cervical carcinoma, as compared to European-like variants. However, an association was found between the HPV 16 E6 L83V variant and the DR*04-DQ*03 haplotype. This association has been observed in several independent studies and shows that both the host HLA class II genotype and viral subtype will affect the risk of an infection progressing into cervical carcinoma.

HPV16 E2 gene disruption and polymorphisms of E2 and LCR: some significant associations with cervical cancer in Indian women

OBJECTIVES

We evaluated the status of the HPV16 E2 gene (disrupted or intact), nucleotide sequence alterations within intact E2 genes and LCR of HPV16 isolates in a group of CaCx cases (invasive squamous cell carcinomas, n = 81) and population controls (normal cervical scrapes, n = 27) from Indian women.

METHODS

E2 disruption was detected by amplifying the entire E2 gene with single set of primers, while overlapping primers were used to determine if any particular region got selectively disrupted. Nucleotide variations in E2 and LCR were analyzed by PCR amplification followed by bi-directional sequencing. The associations between the viral factors and CaCx were analyzed using Fisher's Exact or Chi-squared test and interpreted as OR (95% CI) and P values.

RESULTS

E2 disruption was significantly higher among the cases [3.38 (1.07-10.72); P = 0.02], which was maximum in the region between nucleotides 3650 and 3872 (DNA-binding region). The European (E) variant was found to be the prevalent subgroup (87.76% among cases and 96.30% among the controls), and the remaining samples were Asian-American variants. Among the E subgroup, variation at position 7450 (T > C) within the E2-binding site-IV was found to be significantly higher among the E2 undisrupted cases (21/37; 56.76%), compared to controls (5/18; 27.78%) [3.41 (1.01-11.55); P = 0.03].

CONCLUSIONS

Besides HPV16 E2 disruption, LCR 7450T > C variation within undisrupted E2 of E subgroup appears to be a major factor contributing to the risk of CaCx development in Indian women. Furthermore, polymorphisms in the E2 gene of HPV16 may not be significant for disease risk.

Variants of human papillomaviruses 16 and 18 and their natural history in human immunodeficiency virus-positive women

Highly oncogenic human papillomavirus (HPV) 16 and 18 variants might be expected to be particularly aggressive in HIV-positive women. The association of HPV16 and 18 variant lineages with race, human immunodeficiency virus (HIV) coinfection, CD4+ T-cell count, HIV-RNA level, time-to-clearance of HPV infection and presence of squamous intraepithelial lesions (SIL) among women in the Women's Interagency HIV Study was studied. Subjects were followed semi-annually with Pap smear and cervicovaginal lavage (CVL). HPV DNA was detected in CVLs using MY09/11 L1 PCR assay. Specimens positive for HPV16/18 underwent E6 PCR and sequencing to determine the variant present. Specimens from 195 HPV16- and 162 HPV18-positive women were classified into variant lineages based on sequencing results. African variants of HPV16 and HPV18 were significantly more prevalent among African-Americans than among Caucasians [42 versus 14 % (P=0·001) and 60 versus 13 % (P<0·001), respectively]. However, it was not possible to detect associations between the HPV16 or 18 variant lineages and other factors studied. African variants of HPV16/18 were more common in women of African descent living outside Africa, which could reflect mixing behaviours and/or immunogenetic factors. However, in a large population of HIV-infected women, the variant of HPV16 or 18 was unrelated to persistence of infection or presence of SIL. If non-European variants are more oncogenic, the effect may involve a late stage in cervical tumorigenesis.