Human papillomavirus and cervical carcinogenesis

Molecular cloning, biophysical and in silico studies of Human papillomavirus 33 E2 DNA binding domain

Human papillomavirus 33, a high-risk HPV strain, is mainly responsible for HPV infection and cervical cancer in Asian countries. The E2 protein of HPV 33 is a DNA-binding protein that plays a crucial role in viral replication and transcription. We have cloned, overexpressed, and purified the DNA binding domain of the E2 protein. Size exclusion chromatography results suggested that the protein exists in a homodimeric state in the native form. Circular dichroism data showed that the protein has a higher content of β-sheet. The melting temperature obtained from differential scanning calorimetry is 52.59 °C, and the protein is stable at pH 8 and is in a dimeric form at basic pH. The protein is monomeric or unfolded at a very low pH. Chemical denaturation studies suggested that the protein denatured and dissociated simultaneously. The DNA binding activity of the protein was also confirmed and it showed binding affinity in the order of 106 M-1. The protein structure was modeled using homology modeling and other bioinformatic tools. The virtual screening and molecular dynamic simulation studies were performed to find compounds that can act as potent inhibitors against E2 DBD. This study expands the understanding of the conserved structural and binding properties of HPV33 E2 DBD and provides the first report on the characterization of the viral protein.Communicated by Ramaswamy H. Sarma.

Comparative Analysis of Conventional Cytology and Liquid-Based Cytology in the Detection of Carcinoma Cervix and its Precursor Lesions

Context

The conventional smears (CS) and Liquid based cytology (LBC) are important tools to detect carcinoma cervix and its precursor lesions.

Aims

The present study was done to compare the cytomorphological features of cervical lesions using both techniques and compare with the histopathological diagnosis.

Settings and Design

This was a prospective observational study over a period of 1.5 years at a tertiary care hospital.

Methods and Material

A total of 969 women in the age group of 21-65 years presenting with either routine screening or complaints of vaginal bleeding, discharge, or pelvic pain were enrolled for the study. Both the CS and LBC smears were analyzed and compared with the corresponding histopathology diagnosis. The data was analyzed using Statistical Package for the Social Sciences (SPSS) software and P values <0.05 were considered significant.

Results

There were 8.57% unsatisfactory smears in CS as compared to 0.5% in LBC smears. Liquid-based cytology was superior to conventional preparations in terms of smear adequacy, lesser hemorrhagic and inflammatory background, and presence of more endocervical cells. Liquid-based cytology showed a better yield in detecting all the types of epithelial cell lesions with a concordance rate of 73.9% between the two techniques. On histopathology correlation of these lesions, LBC had a higher sensitivity (96.67%) and diagnostic accuracy (99.08%) as compared to CS (73.33% and 92.66%, respectively).

Conclusions

Liquid-based cytology is superior to conventional cytology for the detection of epithelial cell lesions. Reduction in the unsatisfactory smears, a cleaner background, and better representation of the sample are more significantly appreciated on LBC in contrast to CS.

C33-A cells transfected with E6*I or E6*II the short forms of HPV-16 E6, displayed opposite effects on cisplatin-induced apoptosis

The HPV-16 E6/E7 bicistronic immature transcript produces 4 mature RNAs: the unspliced HPV-16 E6/E7^pre-mRNA product and 3 alternatively spliced mRNAs. The 3 spliced mRNAs encode short forms of the E6 oncoprotein, namely E6*I, E6*II and E6^E7. In this study we showed that transfection of C-33A cells with monocistronic constructs of these cDNAs fused to GFP, produced different effects on apoptosis, after the treatment with cisplatin. Transfection of C-33A cells with the full-length E6-GFP oncoprotein resulted in a 50% decrease in cell death, while the transfection with the E6*I-GFP construct showed only a 25% of diminution of cell death, compared to the control cells. Transfection with the E6^E7-GFP or E7-GFP construct had no effect on the number of the apoptotic cells, compared with control cells. Conversely, transfection with the E6*II construct resulted in higher cell death than the control cells. Taken together, these results suggested that E6*I or E6*II, the short forms of HPV-16 E6, displayed opposite effects on cisplatin-induced apoptosis, when transfected in C-33A cells.

Site of infections associated with human papillomavirus

INTRODUCTION

Human papillomavirus (HPV) is the most clinically common sexually transmitted infection due to its carcinogenic power and the high number of lesions that it causes at different sites of the human body.

MATERIAL AND METHODS

Genital tract organs are the most common sites where the virus can be found, but by increasing the sensitivity of diagnostic technique, it is possible to identify viral presence in different regions of the body such as the stomach, the lung, and the urinary tract. These findings break with the traditional HPV skin/genital tropic profile and demonstrate that the virus is capable of infecting a wide variety of cells, tissues, and organs or can, at least, survive in these areas. The widespread presence of the HPV in the human body, often in latent form, led us to consider the hypothesis that HPV latency may be associated with no disease.

CONCLUSION

This observation raises further questions about the possibility of the virus not causing disease in specific sites of the human body, but rather, behaving like a commensal/opportunistic microorganism.

The regulation of inflammatory pathways and infectious disease of the cervix by seminal fluid

The connection between human papillomavirus (HPV) infection and the consequent sequelae which establishes cervical neoplastic transformation and invasive cervical cancer has redefined many aspects of cervical cancer research. However there is still much that we do not know. In particular, the impact of external factors, like seminal fluid in sexually active women, on pathways that regulate cervical inflammation and tumorigenesis, have yet to be fully understood. HPV infection is regarded as the initiating noninflammatory cause of the disease; however emerging evidence points to resident HPV infections as drivers of inflammatory pathways that play important roles in tumorigenesis as well as in the susceptibility to other infections such as human immunodeficiency virus (HIV) infection. Moreover there is emerging evidence to support a role for seminal fluid, in particular, the inflammatory bioactive lipids, and prostaglandins which are present in vast quantities in seminal fluid in regulating pathways that can exacerbate inflammation of the cervix, speed up tumorigenesis, and enhance susceptibility to HIV infection. This review will highlight some of our current knowledge of the role of seminal fluid as a potent driver of inflammatory and tumorigenic pathways in the cervix and will provide some evidence to propose a role for seminal plasma prostaglandins in HIV infection and AIDS-related cancer.

Depletion of polycistronic transcripts using short interfering RNAs: cDNA synthesis method affects levels of non-targeted genes determined by quantitative PCR

Background

Short interfering RNAs (siRNAs) are often used to deplete viral polycistronic transcripts, such as those encoded by human papillomavirus (HPV). There are conflicting data in the literature concerning how siRNAs targeting one HPV gene can affect levels of other genes in the polycistronic transcripts. We hypothesised that the conflict might be partly explained by the method of cDNA synthesis used prior to transcript quantification.

Findings

We treated HPV16-positive cervical keratinocytes with siRNAs targeting the HPV16 E7 gene and used quantitative PCR to compare transcript levels of E7 with those of E6 and E2, viral genes located upstream and downstream of the target site respectively. We compared our findings from cDNA generated using oligo-dT primers alone with those from cDNA generated using a combination of random hexamer and oligo-dT primers. Our data show that when polycistronic transcripts are targeted by siRNAs, there is a period when untranslatable cleaved mRNA upstream of the siRNA binding site remains detectable by PCR, if cDNA is generated using random hexamer primers. Such false indications of mRNA abundance are avoided using oligo-dT primers. The period corresponds to the time taken for siRNA activity and degradation of the cleaved transcripts. Genes downstream of the siRNA binding site are detectable during this interval, regardless of how the cDNA is generated.

Conclusions

These data emphasise the importance of the cDNA synthesis method used when measuring transcript abundance following siRNA depletion of polycistronic transcripts. They provide a partial explanation for erroneous reports suggesting that siRNAs targeting HPV E7 can have gene-specific effects.

Comparison of oncogenic HPV type-specific viral DNA load and E6/E7 mRNA detection in cervical samples: results from a multicenter study

High-risk human papillomavirus (HR-HPV) genotype viral load and E6/E7 mRNA detection are proposed as surrogate markers of malignant cervical lesion progression. Currently, the use of commercially available DNA-based or mRNA-based tests is under investigation. In this study, the viral DNA load and E6/E7 mRNA detection of the five most common HR-HPV types detected in cervical cancer worldwide were compared in 308 cervical samples by using in-house type-specific quantitative real-time PCR assays and PreTect HPV-Proofer test, respectively. Sensitivity and negative predictive values were higher for the HPV-DNA assays combined (95.0% and 96.0%, respectively) than the RNA assays (77.0% and 88.0%, respectively); conversely, the mRNA test showed a higher specificity and higher positive predictive value (81.7% and 66.9%, respectively) than the DNA test (58.6% and 52.5%, respectively) for detecting histology-confirmed high-grade cervical intraepithelial neoplasia. A significantly higher association between viral DNA load and severity of disease was observed for HPV 16 and 31 (γ = 0.62 and γ = 0.40, respectively) than for the other HPV types screened. A good degree of association between the two assays was found for detection of HPV 16 (k = 0.83), HPV 18 (k = 0.72), HPV 33 (k = 0.66), and HPV 45 (k = 0.60) but not for HPV 31 (k = 0.24). Sequence analysis in L1 and E6-LCR regions of HPV 31 genotypes showed a high level of intra-type variation. HR-HPV viral DNA load was significantly higher in E6/E7 mRNA positive than negative samples (P < 0.001), except for HPV 31. These findings suggest that transcriptional and replicative activities can coexist within the same sample.

Cutaneous squamous cell carcinoma and human papillomavirus: is there an association?

BACKGROUND

The role of human papillomavirus (HPV) in the induction and maintenance of cervical, anogenital, and some oropharyngeal carcinomas is well recognized, but its role in cutaneous squamous cell carcinoma (SCC) remains to be elucidated. HPV is thought to act as a possible cocarcinogen in the development of SCC.

OBJECTIVE

To review the literature assessing the correlation between and possible causation of HPV and cutaneous SCC in immunocompetent and immunocompromised populations.

METHODS

We reviewed HPV sampling and detection methods, epidemiologic studies examining HPV carriage in immunocompetent and immunosuppressed individuals, and evidence asserting an association between HPV and cutaneous SCC.

RESULTS

Although an abundant body of evidence points toward a link between HPV and cutaneous SCC, many studies indicate otherwise. Recent studies have focused on viral activity in addition to DNA presence.

CONCLUSION

The possibility exists that HPV may play a role in the induction but not maintenance of cutaneous SCC.

Pathology and epidemiology of HPV infection in females

Human papillomaviruses (HPVs) are a large family of small double-stranded DNA viruses that infect squamous epithelia. It has been established that infection with specific HPV types is a contributing factor to different types of anogenital cancer, including vulval, vaginal, anal, penile, and head and neck cancers. Approximately 4% of all cancers are associated with HPV. HPV infection is the major cause of cervical cancer and genital warts. Genital HPV infections are very common, are sexually transmitted, and have a peak prevalence between ages 18 and 30. Most of these infections clear spontaneously, but in 10-20% of women, these infections remain persistent and are at risk of progression to grade 2/3 cervical intraepithelial neoplasm (CIN) and eventually to invasive cancer of the cervix (ICC). CINs are genetically unstable lesions with a 30-40% risk of progression to ICC. If left untreated, they form a spectrum of increasing cytological atypia, ranging from low-grade CIN1 to high-grade CIN3; the latter are caused almost exclusively by high-risk HPVs, HPV 16 and 18. Infection with HPV requires a microabrasion in the genital epithelium. The oncogenic properties of high-risk HPV reside in the E6 and E7 genes, which if inappropriately expressed in dividing cells deregulate cell division and differentiation. HPV DNA testing has been shown consistently to be superior to cytology in terms of sensitivity and positive predictive value and will become a major tool in cervical cancer screening, at least in the developed countries.

Activation of the interleukin-32 pro-inflammatory pathway in response to human papillomavirus infection and over-expression of interleukin-32 controls the expression of the human papillomavirus oncogene

High-risk variants of human papillomavirus (HPV) induce cervical cancer by persistent infection, and are regarded as the principal aetiological factor in this malignancy. The pro-inflammatory cytokine interleukin-32 (IL-32) is present at substantial levels in cervical cancer tissues and in HPV-positive cervical cancer cells. In this study, we identified the mechanism by which the high-risk HPV-16 E7 oncogene induces IL-32 expression in cervical cancer cells. We used antisense transfection, over-expression, or knock-down of IL-32 to assess the effects of the HPV-16 E7 oncogene on IL-32 expression in cervical cancer cells. Cyclo-oxygenase 2 (COX-2) inhibitor treatment was conducted, and the expression levels, as well as the promoter activities, of IL-32 and COX-2 were evaluated in human HPV-positive cervical cancer cell lines. E7 antisense treatment reduced the expression levels and promoter activities of COX-2, which is constitutively expressed in HPV-infected cells. Constitutively expressed IL-32 was also inhibited by E7 antisense treatment. Moreover, IL-32 expression was blocked by the application of the selective COX-2 inhibitor, NS398, whereas COX-2 over-expression resulted in increased IL-32 levels. These results show that the high-risk variant of HPV induces IL-32 expression via E7-mediated COX-2 stimulation. However, E7 and COX-2 were down-regulated in the IL-32γ over-expressing cells and recovered by IL-32 small interfering RNA, indicating that E7 and COX-2 were feedback-inhibited by IL-32γ in cervical cancer cells.

Correlation of p53 and Ki-67 (MIB-1) expressions with clinicopathological features and prognosis of early stage cervical squamous cell carcinomas

AIM

To evaluate the prognostic significance of the expression of p53 and Ki-67, and their correlation with various clinicopathological factors in patients with squamous cell carcinoma of the uterine cervix treated by radical hysterectomy.

METHODS

Two hundred and thirty five patients diagnosed between 1987 and 2004 were investigated for p53 and Ki-67 expression by immunohistochemistry. The relationship of these proteins and other potential prognostic factors with recurrence-free survival (RFS) was evaluated.

RESULTS

The mean age of the patients was 43.9 years (range, 27-68). There were 28 cases with stage IA2 (11.9%) and 207 cases with stage IB1 (88.1%). The overall 5-year RFS was 91.1% (95% confidence interval [CI] 86.0, 94.4). p53 and Ki-67 expressions were seen in 33.6% and 81.3% of cases, respectively. p53 expression was significantly associated only with parametrial or marginal involvement (P = 0.005), while Ki-67 expression significantly correlated only with larger tumor (P = 0.011) and parametrial or marginal involvement (P = 0.024). There was significant correlation between the expression of p53 and Ki-67 (P = 0.021). In multivariate analysis, Ki-67 expression (hazard ratio for >or=3rd vs 1st tertile [>or=30% vs <20% expression] = 16.0, 95%CI 2.1-124.5; P = 0.0015) appeared to be an independent prognostic factor for RFS, while no prognostic significance of p53 expression was found.

CONCLUSION

Ki-67 expression is an independent prognostic parameter for RFS in patients with early stage squamous cell carcinoma of the uterine cervix. Ki-67 expression at or above the cut-off point of 30.0% had significantly poorer RFS.

Lack of heterogeneity of HPV16 E7 sequence compared with HPV31 and HPV73 may be related to its unique carcinogenic properties

To assess the role of human papillomavirus virus (HPV) genetics in cervical lesions, we sequenced the E7 gene of HPV16, 31, or 73 from singly infected women who (1) cleared the infection quickly, (2) had type-specific persistent infection, or (3) progressed to CIN2 or worse lesions. Four of the 296 HPV16 E7 nucleotides were variable, compared with 7 of 296 for HPV31 E7 and 4 of 296 for HPV73 E7. While most of the polymorphisms in HPV31 and -73 resulted in non-synonymous amino acid changes, the polymorphisms in the HPV16 E7 resulted in synonymous changes. The lack of heterogeneity of HPV16 E7 suggests high evolutionary purifying selection that might be related to the unique carcinogenicity of HPV16.

Tumor Morphology and Immunohistochemical Expression of Estrogen Receptor, Progesterone Receptor, p53, and Ki67 in Urogenital Carcinomas of California Sea Lions (Zalophus californianus)

Metastatic carcinoma of urogenital origin is a common cause of mortality in free-ranging California sea lions (Zalophus californianus). The etiology of this cancer is likely multifactorial, with viral infection, genetic factors, and exposure to environmental organochlorine contaminants possible contributing factors. In this study, expression of estrogen receptor α (ER α), progesterone receptor (PR), p53, and Ki67 were evaluated by immunohistochemistry in 12 sea lions with metastatic carcinoma, genital epithelial dysplasia, and intraepithelial neoplasia; 4 with genital epithelial dysplasia and intraepithelial neoplasia without metastases; and 6 control animals. Dysplastic and neoplastic lesions were identified in multiple areas of the cervix, vagina, penis, prepuce, and urethra in affected animals, suggesting multicentric development. Lesions were graded according to degree of epithelial dysplasia and infiltration and lesions of different grades were evaluated separately. Estrogen receptor expression was lower in intraepithelial lesions compared with normal genital epithelium, and expression in metastatic lesions was completely absent. There was progesterone receptor expression in neoplastic cells in intraepithelial lesions of all grades and in metastases, with no significant difference between lesion grades or between control and affected epithelium. Ki67 index and p53 expression increased with lesion grade and were higher in lesions than normal epithelium. Metastatic tumors exhibited highly variable morphology; however, proliferation index, ER α, PR, and p53 expression were similar in tumors with different patterns of growth. These results suggest that endogenous hormones, environmental contaminants that interact with steroid hormone receptors, and alterations in p53 may play a role in urogenital carcinogenesis in California sea lions.

Biomarkers in cervical precancer management: the new frontiers

The major cause of cervical cancer and its pre-invasive lesions is persistent infections with oncogenic human papillomavirus (HPV). Viral replication and integration in the cervix depends on the ordered expression of viral gene products, which can lead to overexpression of multiple molecular proteins or biomarkers. These novel biomarkers allow the monitoring of essential molecular events in histological or cytological specimens and are likely to improve the detection of lesions that have a high risk of progression in both primary screening and triage settings. This review focuses on these molecular markers and their role in the diagnosis and management of cervical dysplasia and cancer.

Prevention, diagnosis, and treatment of cervical cancer

This article reviews the current data on human papillomavirus as the cause of most cervical cancer cases, data on the recently approved human papillomavirus vaccines, and updated information concerning the Bethesda System for interpretation of Papanicolaou test results. Current recommendations for surgical treatment, concurrent chemotherapy, and radiation therapy and recent advances in systemic therapy for advanced or metastatic cervical cancer are reviewed.

Human papillomavirus in cervical screening and vaccination

Recent decades have witnessed a reduction in the incidence of cervical cancer in countries where screening programmes have achieved broad coverage. The recognized importance of high-risk HPV (human papillomavirus) infection in the aetiology of cervical cancer may introduce a role for HPV DNA testing in cervical screening programmes. Positive HPV DNA tests indicate women at risk of cervical cancer with greater sensitivity, but reduced specificity, compared with exfoliative cytology. Combining HPV testing with cytology may be useful in the triage of minor cytological abnormalities into those requiring referral to colposcopy (HPV positive) compared with those who can be safely managed by cytological surveillance (HPV negative). With its high sensitivity and high-negative-predictive value, HPV testing may also be useful for predicting treatment failure, since residual disease is very unlikely in the event of a negative HPV test. Ultimately, prevention is better than cure, and the advent of HPV prophylactic vaccines may obviate the need for population-based cervical screening programmes in the future. A multivalent vaccine administered to adolescents prior to the onset of sexual activity and boosted at regular intervals throughout their sexually active life may provide protection against type-specific HPV infection, malignant precursors and invasive cervical disease. Several large randomized placebo-controlled trials have been conducted with promising results. For those generations of women already exposed to high-risk HPV infection, therapeutic vaccines may offer advantages over conventional treatment, although much work still needs to be done.

Increased Ki-67 proliferative index and absence of P16INK4 in CIN-HPV related pathogenic pathways different from cervical squamous intraepithelial lesion

BACKGROUND/AIM

It is generally assumed that similar pathways are involved in human papillomavirus (HPV) induced pathogenesis of cervical squamous intraepithelial lesions (SILs) and cancers and a subset of conjunctival intraepithelial neoplasm (CIN)-that the malignancies or pre-cancerous lesions arise through HPV oncoproteins E6 and E7, which disrupt the pathways of p53 and the product of the retinoblastoma (Rb) gene and, in turn, increase the protein product of gene p16INK4 through the mechanism of positive feedback. Several cell cycle molecules are detected to test this hypothesis.

METHODS

Nine cases of CIN and eight non-CIN cases were analysed for the expression of Ki-67, pRb, p53, and p16INK4 via immunohistochemistry. Nine cases of cervical high grade squamous intraepithelial lesion (HSIL), and 10 cases of cervical low grade squamous intraepithelial lesion (LSIL) were included for stain control of p16INK4a, and comparison of p16INK4a expression to CIN cases. A nested polymerase chain reaction and a genechip HPV typing were used to detect HPV infection and types in the CIN and non-CIN samples

RESULTS

HPV positivity was demonstrated in all of the CIN lesions but in none of the non-CIN lesions. The Ki-67 proliferative index (Ki-67 PI) was statistically higher in the CIN group than the non-CIN group; however, there were no differences of expression of pRb and p53 between the two groups and no expression of p16INK4 in all cases. All nine cases of HSIL, and seven out of 10 cases of LSIL used for stain control were immunoreactive for p16INK4a. There were statistically significant differences in overexpression of p16INK4a between the CINs and SILs

CONCLUSIONS

The Ki-67 proliferative index may be a sensitive marker for CIN lesions and these results, with significant differences in overexpression of p16INK4a between CINs and SILs, may provide new evidence that HPV related mucosal dysplasia in different anatomical locations may lead to dissimilar molecular pathways.

Human papillomavirus 16 infection in adenocarcinoma of the cervix

The impact of the success of organised cervical screening programme results in a steady decline of the incidence of squamous cell carcinoma of the cervix but a concomitant increase in the incidence of the less common histological subtypes, particularly adenocarcinoma of the cervix (ACC). Although Human papillomavirus (HPV) infection is believed to be a necessary cause of cervical cancer, its role in the pathogenesis of ACC is not well established. Established associations between oncogenic strains of HPV and ACC are based on molecular studies carried out on entire tumour block sections. In this study, the cervical adenocarcinoma cells of a 10-year cohort of women diagnosed with ACC were dissected using the PixCell II Laser Microdissecting System to detect the HPV 16 genome sequence using the real-time quantitative polymerase chain reaction to confirm the presence of HPV DNA within ACC cells. By coupling these two sophisticated techniques, the HPV DNA copy number cell could be calculated to investigate its role. The prevalence of HPV 16 infection in this cohort was 24%, which is significantly higher than the control group (chi(2), P=0.014). Women with ACC also had significantly higher HPV DNA copy number per cell compared to the control group (P=0.00007). Higher HPV DNA copy number is associated with risk of developing ACC.

Biologia molecular do câncer cervical

A carcinogênese é um processo de múltiplas etapas. Alterações no equilíbrio citogenético ocorrem na transformação do epitélio normal a câncer cervical. Numerosos estudos apoiam a hipótese de que a infecção por HPV está associada com o desenvolvimento de alterações malignas e pré-malignas do trato genital inferior. Neste trabalho são apresentadas as bases para a compreensão da oncogênese cervical. O ciclo celular é controlado por proto-oncogenes e genes supressores. Quando ocorrem mutações, proto-oncogenes tornam-se oncogenes, que são carcinogênicos e causam multiplicação celular excessiva. A perda da ação de genes supressores funcionais pode levar a célula ao crescimento inadequado. O ciclo celular também pode ser alterado pela ação de vírus, entre eles o HPV (Human Papiloma Virus), de especial interesse na oncogênese cervical. Os tipos de HPV 16 e 18 são os de maior interesse, freqüentemente associados a câncer cervical e anal. O conhecimento das bases moleculares que estão envolvidas na oncogênese cervical tem sido possível devido a utilização de técnicas avançadas de biologia molecular. A associação destas técnicas aos métodos diagnósticos clássicos, poderão levar a uma melhor avaliação das neoplasias cervicais e auxiliar no desenvolvimento de novas terapias, talvez menos invasivas e mais efetivas.

The role of p-STAT3 (ser727) revealed by its association with Ki-67 in cervical intraepithelial neoplasia

OBJECTIVES

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) has been described in many types of cancers. However, the role of phospho-STAT3 (p-STAT3) at serine residue 727 is in large part undetermined. Our purposes of this study were to evaluate the expression patterns of p-STAT3 (ser727) in cervical intraepithelial neoplasia (CIN) and to explore its possible role in the progression of cervical cancer.

METHODS

Paraffin-embedded sections from 56 patients including 20 CIN 1, 10 CIN 2, and 26 CIN 3 were collected in this study. Immunohistochemical analysis was performed, and the expression patterns of p-STAT3 (ser727) were categorized by semiquantitative method and further correlated with the CIN histopathologic grade using the chi(2) test with Bonferroni adjustment for multiple comparisons and with the proliferation marker Ki-67 expression using Fisher's Exact Test.

RESULTS

The categorized high p-STAT3 (ser727) expression group in nuclei of dysplastic cells was significantly higher in CIN 3 (76.92%), in comparison with CIN 1/2 (13.33%, P < 0.001). Moreover, both the nuclear and cytoplasmic p-STAT3 (ser727) expressions were correlated with Ki-67 nuclear staining (P < 0.001 and < 0.001, respectively).

CONCLUSIONS

Our result revealed that aberrant expression levels of p-STAT3 (ser727) were significantly correlated with CIN lesion grade and cell proliferation. Evaluation of p-STAT3 (ser727) expression may provide additional prognostic information for the clinical course of the disease and therefore to be developed as a prognostic indicator for cervical cancer.

Human papillomavirus E6/E7 mRNA expression in women younger than 30 years of age

OBJECTIVE

The prevalence of human papillomavirus (HPV) is high in women younger than 30 years of age, most infections being transient. It is not clear, however, to what extent the E6/E7 transcripts are being expressed. This may be of prognostic importance. In this study, we have determined the prevalence of HPV DNA and mRNA in 283 women younger than 30 years of age.

METHODS

E6/E7 transcripts from HPV types 16, 18, 31, 33 and 45 were detected using PreTect HPV-Proofer, while the presence of HPV DNA was detected using Gp5+/6+ consensus PCR and type-specific PCR.

RESULTS

A total of 92 women (32.5%) were positive by consensus PCR, 59 (20.8%) were positive by type-specific PCR, while 41 (14.5%) were positive by PreTect HPV-Proofer. E6/E7 mRNA expression was detected in 38 (64.4%) of the 59 HPV type-specific DNA positive women. For HPV 16, E6/E7 mRNA expression was observed in 8 (32%) of the 25 DNA positive women. No high-grade lesions were observed in the concomitant cytology.

CONCLUSIONS

Among young women having a normal Pap smear, a high HPV prevalence was found. Hence, use of consensus PCR will most probably give a low prognostic value for identifying subsequent severe dysplasia. The five HPV types 16, 18, 31, 33 and 45 accounted for the majority of infections with two out of three having a detectable E6/E7 mRNA expression. Yet, repeated type-specific testing for HPV mRNA may identify young women with a persistent transforming infection being at increased risk for severe dysplasia.

Recent developments in human papillomavirus vaccines

The association of certain high-risk human papillomaviruses with the development of anogenital cancer in humans is well-established. Numerous preclinical studies have underwritten the development of both prophylactic and therapeutic vaccine candidates for clinical evaluation. Prophylactic strategies are utilising virus-like particles composed of the L1 viral capsid protein to induce neutralising antibodies while therapeutic approaches are aimed at generating specific T cells targeted at the viral E6 and/or E7 oncogene products. Thus far, human papillomavirus virus-like particle vaccines have proven to be clinically efficacious in the early trials looking at the prevention of infection. Important future milestones will be showing the prevention of high-grade cervical intraepithelial neoplasia and sufficient longevity for such protection. Different types of therapeutic vaccines including peptide, protein, DNA or viral vector-based vaccines have proven to be safe and immunogenic in patients, although there is often no correlation with clinical outcome. The possibility of combined prophylactic and therapeutic vaccines may offer the best chance for a significant reduction in the incidence of death from cervical cancer worldwide.

Cancer incidence and survival for indigenous Australians in the Northern Territory

OBJECTIVE

To compare cancer incidence and survival for the Northern Territory (NT) Indigenous population with that of other Australians, and to assess NT Indigenous incidence time trends.

METHODS

Cancer registry data were used to calculate cancer incidence rate ratios (NT Indigenous to total Australian), the average annual change in NT Indigenous cancer incidence and the relative risk of cancer death after diagnosis of cancer (NT Indigenous to combined Western Australian and Tasmanian cases) for 1991-2001.

RESULTS

For NT Indigenous people, incidence rates were high for cancers of the liver, gallbladder, cervix, vulva and thyroid and, in younger people only, for cancers of the oropharynx, oesophagus, pancreas and lung, but low for cancers of the colon and rectum, breast, ovary, prostate, bladder, kidney, melanoma and lymphoma. Incidence rate ratios ranged from 0.1 for melanoma to 7.4 for liver cancer. Incidence increased for breast and pancreatic cancers. Survival was low for almost all specific cancers examined, and for all cancers combined (relative risk of death 1.9, 95% CI 1.7-2.1).

CONCLUSIONS

Compared with other Australians, NT Indigenous people have higher, and increasing, incidence for some cancers (particularly smoking-related cancers) and lower survival for most.

IMPLICATIONS

Cancer has a greater impact on NT Indigenous people than other Australians. Well-established cancer risk factors should be more effectively tackled in Indigenous people and known effective screening programs more effectively implemented. Research is urgently required into the reasons why survival from cancer in NT Indigenous people is so much lower than in other Australians.

Immune responses to human papillomavirus in genital tract of women with cervical cancer

OBJECTIVES

To address a question whether immune responses to HPV infection play a role in control of cervical cancer, we analyzed systemic and mucosal immune responses to HPV in women who underwent radical hysterectomy for cervical cancer (HCC) or loop conization due to cervical dysplasia (LOOP), or had hysterectomy for other reasons (HNN).

METHODS

HPV-specific antibodies in sera and vaginal washes were determined by ELISA using recombinant HPV 16 E7 oncoprotein. Cytokines in vaginal washes were assayed by Linco cytokine multiplex method using Luminex technology. Differential gene expression profiling in cervical tumor was determined by microarray analysis and Real-time RT-PCR.

RESULTS

While levels of HPV-16 E7-specific IgG in vaginal wash were significantly higher in women undergoing HCC and HNN, the levels of the HPV-16 E7-specific IgA in vaginal wash of women with cervical cancer and cervical dysplasia were lower as compared to patients in HNN. Proinflammatory cytokines, such as IL-6 and IL-8, were dominant in vaginal washes of all subjects studied. However, no pattern of Th1-type and Th2-type cytokine induction was observed as demonstrated by protein analysis as well as differential gene expression profiling in cervical tumor.

CONCLUSIONS

These results suggest a selective down-regulation of local HPV-specific IgA responses in women with cervical cancer.

Comparison of Human Papillomavirus Messenger RNA and DNA Detection: A Cross-sectional Study of 4,136 Women >30 Years of Age with a 2-Year Follow-up of High-Grade Squamous Intraepithelial Lesion

The purpose of this study was to compare the detection of human papillomavirus (HPV) DNA with detection of mRNA. The study included 4,136 women >30 years of age. E6/E7 mRNA expression from the carcinogenic HPV types 16, 18, 31, 33, and 45 was detected by the PreTect HPV-Proofer assay, whereas the presence of HPV DNA was detected by Gp5+/6+ consensus PCR followed by type-specific PCR. A total of 4.0% had an abnormal cytologic diagnosis, 3.0% were positive by PreTect HPV-Proofer, 4.4% by type-specific PCR, and 10.4% by consensus PCR. For detection of HPV in high-grade squamous intraepithelial lesion (HSIL), no significant difference was observed between PreTect HPV-Proofer and consensus PCR. For women with a cytologic normal, atypical squamous cell of uncertain significance, and low-grade SIL diagnosis, the detection rate of HPV was significantly higher by Gp5+/6+ consensus PCR (P < 0.005) than by PreTect HPV-Proofer. Histology confirmed 14 of 23 cytologic HSIL as cervical intraepithelial neoplasia grade >2. Of these women, PreTect HPV-Proofer and type-specific PCR detected 12, whereas consensus PCR detected 13. In conclusion, for HSIL, detection of E6/E7 transcripts from HPV types 16, 18, 31, 33, and 45 are present to the same degree as DNA detected by consensus PCR. Equally important, only a small proportion of the HPV DNA-positive women with a normal, atypical squamous cell of uncertain significance or low-grade SIL diagnosis had a detectable mRNA expression. HPV E6/E7 mRNA detection by PreTect HPV-Proofer represents a new promising test as an adjunct to cytology.

Expression of p53, Ki-67, and CD31 in the vaginal margins of radical hysterectomy in patients with stage IB carcinoma of the cervix

OBJECTIVES

This study was undertaken to evaluate the expression of p53, Ki-67, and CD31 both in the tumor and in the vaginal margins of radical hysterectomy in patients with stage IB squamous cell carcinoma of the cervix, as an attempt to use these proteins as possible markers for residual tumor in cervical cancer.

METHODS

Thirty patients with stage IB squamous cell carcinoma of the cervix were submitted to radical hysterectomy (study group), and thirty patients with uterine myoma were submitted to vaginal hysterectomy (control group) and were prospectively studied from November 2001 to September 2002. Tissue samples were taken from the tumor or cervix, anterior vaginal margin (AVM), and posterior vaginal margin (PVM) and were immunohistochemically evaluated by monoclonal antibodies for p53, Ki-67, and CD31. Vaginal samples in which the histological examination showed tumor involvement were excluded from the study.

RESULTS

Patient's mean age was 48.7 +/- 10.4 years (27-73 years). The clinical stage was IB1 in 22 patients (73.3%) and IB2 in eight patients (26.7%). The expressions of p53, Ki-67, and CD31 were significantly higher in the tumor than in the benign cervix (P < 0.001). Higher expressions of these markers were noted in the vaginal margins of radical hysterectomy in patients with cervical carcinoma compared to the vaginal margins of control patients. This association was demonstrated for p53 in the AVM proximal (P = 0.045), for Ki-67 in AVM proximal (P < 0.001), AVM distal (P < 0.001), PVM proximal (P = 0.009), and PVM distal (P < 0.001), and for CD31 in AVM proximal (P = 0.003) and AVM distal (P = 0.018). There was no difference in p53, Ki-67, and CD31 expression between the proximal and distal regions of the vaginal margins in patients with carcinoma of the cervix.

CONCLUSION

The expressions of p53, Ki-67, and CD31 were significantly higher in both the histologically positive (cervical tumor) and negative (vaginal margins) tissues of patients who had undergone radical hysterectomy for cervical cancer compared to the benign control tissues.

The regulatory E2 proteins of human genital papillomaviruses are pro-apoptotic

Cervical carcinomas are frequently associated with infection by human papillomaviruses (HPVs). These viruses encode two oncogenes E6 and E7, which promote cell proliferation and immortalization. The viral E2 protein represses transcription of the E6/E7 oncogenes and activates viral DNA replication together with the viral E1 helicase. The E2 protein is specifically inactivated in HPV18-associated carcinoma, suggesting that it may prevent carcinogenic progression. Indeed, E2 was shown to exhibit a strong anti-proliferative action when ectopically expressed in cervical carcinoma cells, as it induces both G1 cell cycle arrest and cell death by apoptosis. While the cell cycle arrest is due to E2-mediated transcriptional repression of the viral oncogenes, the induction of apoptosis appears to be an autonomous function of E2. The amino-terminal transactivation domain (TAD) of the E2 protein is required for its pro-apoptotic activity, but transcriptional transactivation is not involved. E2 induces apoptosis through the extrinsic pathway, involving the initiator caspase 8. In addition, E2 is cleaved by caspases during apoptosis, providing an example of an apoptotic inducer, which is itself a target for caspase cleavage. The cleaved E2 protein exhibits an enhanced apoptotic activity, suggesting that it may participate in an amplification loop. This article reviews our current knowledge of the pro-apoptotic activity of the oncogenic papillomavirus E2 proteins, and discusses the implications for the viral vegetative cycle.

Cervical and vaginal epithelial neoplasms in cynomolgus monkeys

Papillomavirus-associated cervical cancer is the second most common neoplasm in women but has rarely been reported in animals. This report describes cervical and vaginal intraepithelial neoplasms identified in routine histologic specimens obtained from 20 (5.2%) of 385 female cynomolgus macaques (Macaca fascicularis) being used in long-term studies. Lesion incidence was similar in both control and hormonally treated animals (4.7% and 5.5%, respectively). Neoplasms included benign vaginal papillomas, mild to severe intraepithelial dysplasias, and two invasive cervical carcinomas. Common morphologic features included koilocytosis, nuclear atypia, and expansion of the basal epithelium. Selective staining of lesions with at least one of three papillomavirus antibodies was observed in all cases (20 of 20). In contrast, immunostaining of lesions was negative for Epstein-Barr-related virus proteins (0 of 20). The unique similarities between the observed lesions and those seen in women suggest that macaques may provide a suitable animal model for study of papillomavirus oncogenesis.

Acquisition of high-level chromosomal instability is associated with integration of human papillomavirus type 16 in cervical keratinocytes

Whereas two key steps in cervical carcinogenesis are integration of high-risk human papillomavirus (HR-HPV) and acquisition of an unstable host genome, the temporal association between these events is poorly understood. Chromosomal instability is induced when HR-HPV E7 oncoprotein is overexpressed from heterologous promoters in vitro. However, it is not known whether such events occur at the "physiologically" elevated levels of E7 produced by deregulation of the homologous HR-HPV promoter after integration. Indeed, an alternative possibility is that integration in vivo is favored in an already unstable host genome. We have addressed these issues using the unique human papillomavirus (HPV) 16-containing cervical keratinocyte cell line W12, which was derived from a low-grade squamous intraepithelial lesion and thus acquired HPV16 by "natural" infection. Whereas W12 at low passage contains HPV16 episomes only, long-term culture results in the emergence of cells containing integrated HPV16 only. We show that integration of HPV16 in W12 is associated with 3' deletion of the E2 transcriptional repressor, resulting in deregulation of the homologous promoter of the integrant and an increase in E7 protein levels. We further demonstrate that high-level chromosomal instability develops in W12 only after integration and that the forms of instability observed correlate with the physical state of HPV16 DNA and the level of E7 protein. Whereas intermediate E7 levels are associated with numerical chromosomal abnormalities, maximal levels are associated with both numerical and structural aberrations. HR-HPV integration is likely to be a critical event in cervical carcinogenesis, preceding the development of chromosomal abnormalities that drive malignant progression.

The interaction between steroid hormones, human papillomavirus type 16, E6 oncogene expression, and cervical cancer

Various risk factors have been implicated in the causation of cervical cancer including human papillomavirus (HPV), the early genes (E6 and E7 ) of which encode the main transforming proteins. Studies have suggested that steroid hormones may enhance the expression of these genes leading to loss of p53 gene-mediated cell apoptosis. A total of 120 cervical tissue samples were obtained from patients with proven cervical cancer. Patients who used depo-medroxyprogesterone acetate steroid contraception were recruited as part of the steroid arm. Only HPV DNA type 16 samples were used for the study. Controls included three cell lines (CaSki, SiHa, & C33A) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH) was used as an internal housekeeping gene. Of 120 patients, there were 111 patients with HPV type 16 identified. Of this number, RNA was present in 63 samples. There were 30 women (30/63) who used steroid contraception. In relation to patients who used contraception, HPV 16 E6 gene expression was present in 79% (n = 23) and 88% (n = 30) of steroid users compared to nonusers, respectively. In total there were 25 patients (40%) with expression of the HPV 16 E6*I gene and 30 patients with expression of the E6*II gene. There were 57% of steroid users (n = 17) who had expression of the E6*I/E6*II gene, compared to 52% (n = 17) of nonusers (P = 0.800). From a molecular level, this study does not confirm the role of injectable progesterones in cervical carcinogenesis.

Risk factors related to the development and mortality from invasive cervical cancer clinical utility and impact on prevention

The focus of this article is to explore the various risk factors related to cervical cancer and the practical context in which they can be applied. The ability to link dinical outcomes (disease presence, persistence, progression, and recurrence) with antecedent risk factors is strengthened by a new understanding of the molecular mechanisms that are responsible for malignant transformation.

Primary prevention of uterine cervix cancer: focus on vaccine history and current strategy

Primary prevention of uterine cervix cancer spans the gamut of human papillomavirus vaccine development, dietary adjustment, chemoprevention, and risk reduction. Lifestyle and social behaviors impact on risk for cervical cancer. Before examining the growing body of molecular evidence, animal studies, and phase I clinical trials that suggest that a virus-based vaccine for cervical cancer may soon become a reality, one must reflect on what has gone before in the vaccine-based battle with viral disease.

Prognostic factors and new therapeutic approaches to cervical cancer

Recent advances in the detection and therapy of carcinoma of the cervix and its squamous intra-epithelial precursor lesions exploit the knowledge that these lesions are a consequence of infection with high risk (HR) human papillomavirus (HPV). HPV infections over-ride cell cycle controls and antibody based immunodetection of proteins that regulate DNA replication may facilitate mass automated cervical smear screening. Detection of HR HPV DNA in smears from selected patient groups will improve detection of high grade precursor lesions and immunodetection of the cell cycle dependent kinase inhibitor p16(INK4a) seems to specifically and sensitively identify HGSIL. Immunisation with HPV early proteins has been shown to have both prophylactic and therapeutic efficacy in animal papillomavirus infections and immunotherapies for low grade intra-epithelial lesions are realistic. Such vaccines are likely to be combined with immunomodulators in order to maximise the response. Immunotherapies for HPV associated high grade pre-cancers and invasive cancers are problematic in view of tumour immune evasion. However, anti-viral chemotherapies may benefit from the neoplastic phenotypic by the induction of: (1) apoptosis as a consequence of small molecule or anti-sense targeting of individual HPV oncoproteins and (2) replicative senescence by down regulation of the early promoter by E2 or small molecule homologues.

Hygienic hand antiseptics: should they not have activity and label claims against viruses?

Enteric and respiratory viruses are among the most frequent causes of human infections, and hands play an important role in the spread of these and many other viral diseases. Regular and proper hand hygiene by caregivers and food handlers in particular is essential to decontaminate hands and potentially interrupt such spread. What would be considered a proper decontamination of hands? Handwashing with regular soap and water is often considered sufficient, but what of hygienic handwash and handrub antiseptic products? Are they more effective? The evidence suggests that some clearly are. Activity against bacteria may not reflect the ability of hygienic hand antiseptics to deal with viruses, especially those that are nonenveloped. In spite of the acknowledged importance of hands as vehicles for viruses, there is a lack of suitable regulatory mechanism for handwash or handrub products to make claims of efficacy against viruses. This is in contrast with the ability of general-purpose disinfectants to make antiviral claims, although transmission of viruses from surfaces other than those of reusable medical devices may play only a minor role in virus transmission. This review discusses the (1). recent information on the relative importance of viruses as human pathogens, particularly those causing enteric and respiratory infections; (2). the survival of relevant viruses on human hands in comparison with common gram-negative and gram-positive bacteria; (3). the potential of hands to transfer or receive such contamination on casual contact; (4). role of hands in the spread of viruses; (5). the potential of hygienic measures to eliminate viruses from contaminated hands; (6). relative merits of available protocols to assess the activity of hygienic hand antiseptics against viruses; and (7). factors considered crucial in any tests to assess the activity of hygienic hand antiseptics against viruses. In addition, this review proposes surrogate viruses in such testing and discusses issues for additional consideration by researchers, manufacturers, end-users, and regulators.

Restoration of p53 tumor suppressor pathway in human cervical carcinoma cells by sodium arsenite

In most cervical cancer cells, p53 and Rb are disrupted by human papillomaviruses (HPVs) E6 and E7, respectively. Restoration of p53 or Rb function by blocking E6/p53 or E7/Rb pathway might be a potential therapeutic purpose for these cancer cells. Treatment with sodium arsenite (SA) resulted in significant repression of E6 and E7 mRNA levels in SiHa cells. After E6 and E7 repression, p53 was dramatically induced and accumulated in cellular nuclei and Rb was also induced. Two p53-responsive genes, p21(waf1/cip1) and mdm2, were induced after SA treatment. Furthermore, SA also reduced the expressions of Cdc25A and cyclin B, blocked cell cycle progression at G2/M phase, and induced apoptosis in SiHa cells. SA-induced apoptosis was greatly reduced by expression of a dominant-negative mutated p53. In this study, we have first demonstrated that SA did repress E6 and E7 oncogenes, restore the p53 tumor suppressor pathway and induce apoptosis in SiHa cells. Therefore, it would be a potential strategy to promote SA as therapeutic purpose for HPV-positive cancer cells.