Definition of human papillomavirus type 16 DNA levels in low and high grade cervical lesions by a simple polymerase chain reaction technique

Association of Human Papillomavirus Type 16 E7 and HLA Class I Antigen Expression in Cervical Premalignant and Malignant Lesions

In the present experiment we studied the correlation between HPV16 infection and expression of HLA-I antigen in cervical premalignant and malignant lesions (cervicitis, CIN, cervical squamous carcinomas and adenocarcinoma samples). The HPV16 E7 DNA load and the expression of HLA-I antigen in the samples were measured by real-time fluorescence quantitative polymerase chain reaction (RFQ-PCR) and immunohistochemical S-P staining, respectively. Our data indicate that HPV16 E7 load was highly and positively associated with the development of cervical lesions (Spearman's correlation coefficient r=0.848, p<0.001), the negative rate of HLA-I antigen was significantly distinguished among groups (p<0.001), and HPV16 E7 infection and downregulation of HLA-I antigen were highly correlated in cervical lesions (Pearson's correlation coefficient r=-0.487, p<0.001). HPV16 E7 may play an important role in the downregulation of HLA-I antigen in cervical lesions, which results in the immune escape of the virus and the occurrence, development, invasion and metastasis of cancer. Furthermore, quantitative PCR for HPV16 E7 may play an important role in the early detection of cervical diseases and in guiding future therapy toward prevention.

Comparison of the hybrid capture test and polymerase chain reaction in identifying women who have an atypical squamous cell of undetermined significance papanicolaou smear and need colposcopy

OBJECTIVES

The objective of this study was to detect human papillomavirus (HPV) in women with a newly diagnosed atypical squamous cells of undetermined significance (ASCUS) using the hybrid capture (HC) test and the polymerase chain reaction (PCR). We sought to evaluate the accuracy of both tests in identifying women with a concomitant cervical intraepithelial neoplasia (CIN).

MATERIALS AND METHODS

We studied 360 women who had a diagnosis of ASCUS and were referred to the colposcopy clinic. Subjects were between 18 and 50 years, had newly diagnosed ASCUS, had no history of cervical biopsies or treatment, and were not pregnant. A cell sample for HPV testing and colposcopically directed biopsies of lesions were obtained. HPV was detected using the Digene HC and PCR systems (Digene, Silver Spring, MD).

RESULTS

Biopsies showed concomitant CIN in 80 patients (22.2%). Of these, 19 had CIN2 or CIN3. HPV-DNA was detected in 76 of the 360 women (21.1%) using HC and in 166 of 348 women (47.7%) using PCR. The concordance between HC and PCR for detecting HPV was 65%. The sensitivity, specificity, and positive and negative predictive values of HC for detecting CIN were 48%, 86%, 50%, and 85%, respectively. The sensitivity, specificity, and positive and negative predictive values of PCR for detecting CIN were 67%, 58%, 31%, and 86%, respectively. Focusing on CIN2 and CIN3 alone, these values were 79%, 82%, 20%, and 99% for HC, respectively, and 89%, 55%, 10%, and 99% for PCR, respectively.

CONCLUSION

The specificity of HC was higher than the specificity of PCR. For this reason, the HC might be more useful than PCR as a secondary triage method for detecting CIN in women who have incident ASCUS and need colposcopy.

High human papillomavirus oncogene mRNA expression and not viral DNA load is associated with poor prognosis in cervical cancer patients

PURPOSE

Cervical cancer is now known to be caused by infection with an oncogenic type of the human papillomavirus (HPV). However, little is known about the continued role of HPV once cancer has been established. Here, we describe the quantitative relation between HPV DNA copy number and mRNA expression of the viral oncogenes (E6 and E7) and the prognostic value of both measures in cervical cancer patients.

EXPERIMENTAL DESIGN

We studied the number of viral DNA copies and the level of HPV E6/E7 mRNA expression in 75 HPV 16-positive or HPV 18-positive International Federation of Gynecology and Obstetrics stage Ib and IIa cervical cancer patients. Measurements were done with quantitative PCR. DNA copy number analysis was done on pure tumor cell samples enriched with flow sorting. mRNA expression data were compensated for the percentage of tumor cells included.

RESULTS

The number of viral DNA copies was not predictive of survival in cervical cancer patients. In contrast, high HPV E6/E7 mRNA expression was strongly related to an unfavorable prognosis (P = 0.006). In a multivariate Cox model for overall survival, including all known prognostic variables and stratified for HPV type, the level of E6/E7 mRNA expression was an independent prognostic indicator, second only to lymph node status. No correlation was observed between DNA copy number and the level of HPV E6/E7 mRNA expression, which reflects that not all DNA copies are equally transcriptionally active.

CONCLUSIONS

Cervical cancer patients with high HPV E6/E7 oncogene mRNA expression have a worse survival independently from established prognostic factors.

Squamous cell carcinoma of the penis in a man with a human papilloma virus 31 infection

We report a 51-year-old man with squamous cell carcinoma (SCC) on his penis. He was surgically treated for his phimosis when he was 20 years old. He presented with an indurated nodule on the tip of his penis. The tumor was treated with partial penectomy and standard inguinal lymphadenectomy. Histological examination revealed that the tumor was a well-differentiated type of SCC. A polymerase chain reaction was performed to detect human papilloma virus (HPV) DNA. The result revealed the presence of HPV in the SCC. The results of sequencing analysis showed that the DNA was HPV 31.

Quantitative analysis of human papillomavirus type 16 in cervical neoplasm: A study in Chinese population

BACKGROUND

Human papillomavirus (HPV) infection was recognized as a major causal factor for the development and progression of squamous intraepithelial lesions (SIL). It is possible to use HPV test for the detection of cervical lesions as an adjunct to cervical cytology.

OBJECTIVES

To evaluate the relation between HPV 16 viral load and the severity of cervical lesions in a Chinese population.

METHODS

Study population was recruited from the colposcopy and general outpatient clinic. The presence of HPV 16 E6 and E7 in cytological specimens was detected using HPV 16 specific polymerase chain reaction (PCR). The viral load in the specimens that were positive for HPV 16 specific PCR, was quantified by using real-time PCR assay.

RESULTS

The study recruited 394 women, in which 148 were high-grade SIL (HG-L), 121 were low-grade SIL (LG-L) and 125 were Normal. Sufficient DNA integrity was proven in 347 samples. Among 121 positive cases for HPV 16, 70 were HG-L, 34 were LG-L and 17 were Normal. Using quantitative real-time PCR, the percentages of samples with greater DNA copies were found to increase with the severity of diseases. There was also a significant difference in DNA copies among the three groups (HG-L versus Normal, p<0.001; HG-L versus LG-L, p<0.001). Area under receiver operating characteristic (ROC) curve of the HG-L versus LG-L and Normal was 0.836 indicating that quantitative PCR had a good diagnostic value in differentiating HG-L from the LG-L and Normal groups.

CONCLUSIONS

Our data suggested HPV 16 viral load was significantly related to the severity of cervical lesions. Evaluation of viral burden could be a potential clinical tool in management of cervical lesions.

Elevated Amount of Human Papillomavirus 31 DNA in a Squamous Cell Carcinoma Developed from Bowenoid Papulosis

A 50-year-old woman presented with asymptomatic, multiple black macules on the genitalia for 6 months. She presented multiple, round to irregularly shaped, black macules on her labia major and perineum. A keratotic reddish nodule was found on one of the macules. The results of laboratory investigations showed pancytopenia and a decreased CD4/CD8 ratio. A lymphocyte stimulation test showed a decreased response. The histological examination of a biopsy specimen led us to the diagnosis of bowenoid papulosis (BP) for the macules and squamous cell carcinoma (SCC) for the nodule. The macules and nodule were removed successfully. An elevated amount of HPV DNA was demonstrated in SCC compared with that of BP. The HPV DNA in SCC and BP was shown to be HPV-31. These observations indicated that the elevated amount of HPV-31 DNA could have led to the emergence of SCC from BP under the condition of decreased cellular immunity.

Type-specific associations of human papillomavirus load with risk of developing cervical carcinomain situ

We have previously shown that high human papillomavirus (HPV) 16 load in Papanicolaou smears negative for dysplasia is strongly associated with risk for carcinoma in situ (CIS) of the cervix. Here we study the amount of HPV DNA for some of the most frequent high-risk HPV types as determinants of progression to cervical CIS. Real-time PCR is used to estimate the normalized viral load of HPV 16, 18, 31, 33, 35, 39, 45, 52, 58 and 67 in 457 cases of cervical CIS and 552 matched population controls. A total of 2,747 archival Pap smears from gynecologic health examinations, collected over a period of up to 26 years, were analyzed to assess viral load during the infection history. Cervical smear samples differ widely in amount of DNA, underscoring the need for normalization of HPV load to number of cells in the sample. The risk of developing cervical CIS increases with higher viral load for most of the HPV types studied. The range of copy numbers per cell does not differ between HPV types but the odds ratio for CIS in the percentile with highest viral load is substantially higher for HPV 16 (OR = 36.9; 95% CI = 8.9-153.2) than for HPV 31 (OR = 3.2; 95% CI = 1.1-9.1) or HPV 18/45 (OR = 2.6; 95% CI = 1.0-6.4). Therefore, HPV viral load may be predictive of future risk of cervical CIS at a stage when smears are negative for squamous abnormalities, but differences between HPV types need closer attention.

Viral load as a predictor of the risk of cervical intraepithelial neoplasia

HPV infections are believed to be a necessary cause of cervical cancer. Viral burden, as a surrogate indicator for persistence, may help predict risk of subsequent SIL. We used results of HPV test and cytology data repeated every 4-6 months in 2,081 women participating in a longitudinal study of the natural history of HPV infection and cervical neoplasia in São Paulo, Brazil. Using the MY09/11 PCR protocol, 473 women were positive for HPV DNA during the first 2 visits. We retested all positive specimens by a quantitative, low-stringency PCR method to measure viral burden in cervical cells. Mean viral loads and 95% CIs were calculated using log-transformed data. RRs and 95% CIs of incident SIL were calculated by proportional hazards models, adjusting for age and HPV oncogenicity. The risk of incident lesions increased with viral load at enrollment. The mean number of viral copies/cell at enrollment was 2.6 for women with no incident lesions and increased (trend p = 0.003) to 15.1 for women developing 3 or more SIL events over 6 years of follow-up. Compared to those with <1 copy per cell in specimens tested during the first 2 visits, RRs for incident SIL increased from 1.9 (95% CI 0.8-4.2) for those with 1-10 copies/cell to 4.5 (95% CI 1.9-10.7) for those with >1,000 copies/cell. The equivalent RR of HSIL for >1,000 copies/cell was 2.6 (95% CI 0.5-13.2). Viral burden appears to have an independent effect on SIL incidence. Measurement of viral load, as a surrogate for HPV persistence, may identify women at risk of developing cervical cancer precursors.

Diagnosing human papillomaviruses: recent advances

The biological importance of a group of human papillomaviruses, known as high-risk human papillomaviruses, as the key causal agent for almost all cervical cancer has now been established. Many aspects of the natural history of high-risk human papillomaviruses as sexually transmitted infections and as oncogenic agents have been researched. Although human papillomavirus diagnosis is largely confined to DNA detection techniques in cervical smears, there is accumulating evidence that the best polymerase chain reaction and hybrid capture techniques are more sensitive and probably of similar specificity compared with cervical cytology as a triage test for women with borderline smear abnormalities and for screening older women. This is strong presumptive evidence that high-risk human papillomavirus testing could be useful in cervical screening. Current research is aimed at establishing a place for high-risk human papillomavirus testing in routine screening practice. Randomised clinical trials, long-term natural history studies, mathematical modelling, and economic and psychosocial studies are being used to demonstrate whether this testing can improve both the effectiveness and efficiency of cervical screening in a range of situations.

Viral load of human papilloma virus 16 as a determinant for development of cervical carcinoma in situ: a nested case-control study

BACKGROUND

Infection with certain types of human papillomavirus (HPV), which is common among young women, increases the risk of cervical cancer. However, less than 1% of young women positive for oncogenic types of HPV develop cervical cancer. We investigated whether the amount of HPV DNA is a useful predictor of progression to cervical carcinoma in situ.

METHODS

We estimated the amount of HPV 16 DNA by a PCR that uses the 5'-exonuclease (Taqman) method, in 478 women with cervical carcinoma in situ and 608 individually matched controls. To adjust for differences in the amount of genomic DNA between samples, we estimated the amount of a nuclear gene (beta-actin). We studied multiple smears (total 3835 archived samples) from each woman, taken over periods of up to 26 years, that covered normal cytology to development of cervical cancer.

FINDINGS

The risk of cervical carcinoma in situ increased with the amount of HPV 16 DNA. Analysis of the first smear from each woman, collected a mean of 7.8 years before cancer diagnosis, showed that women with the 20% highest amount of HPV 16 DNA were at a 60-fold higher risk of developing cervical carcinoma in situ than women negative for HPV 16. The first smear samples were classified as normal by squamous-cell cytology.

INTERPRETATION

Analysis of the amount of HPV DNA can predict cancer risk at a stage when current screening methods are uninformative. Testing for the amount of HPV 16 DNA during gynaecological health checks might strikingly improve our ability to distinguish between infections that have a high or low risk of progressing into cervical cancer.

Consistent high viral load of human papillomavirus 16 and risk of cervical carcinoma in situ: a nested case-control study

BACKGROUND

Persistent infection with certain types of human papillomavirus (HPV) is believed to be a prerequisite for the development of cervical neoplasia. Persistence may depend on certain characteristics, such as viral load, which has so far been given little attention. We investigated the association between HPV 16 viral load and cervical carcinoma in situ.

METHODS

We did a nested case-control study of women participating in cytological screening in Sweden. We used a sensitive quantitative PCR assay to estimate HPV 16 load in multiple smears for each woman, taken during a period of up to 26 years before diagnosis. We calculated C, values, which decrease as the number of viral DNA copies increases.

FINDINGS

2081 smears from 478 cases and 1754 smears from 608 controls were tested. Among cases, we found a consistently increased load of HPV 16 already 13 years or more before diagnosis, and when many smears were still cytologically normal. Women with high HPV 16 viral loads were at least 30 times the relative risk of HPV-16-negative women more than a decade before diagnosis. The increase in relative risk was constant over time. About 25% of women (95% CI 0.12-0.32) infected with a high viral load before age 25 years developed cervical carcinoma in situ within 15 years.

INTERPRETATION

Cervical carcinoma in situ associated with HPV 16 occurs mainly in HPV-16-positive women who have consistently high viral loads long term. Women at high risk could be identified by use of a quantitative HPV test in addition to cytological screening.

Infection and cervical intraepithelial neoplasia

The impact of sexually transmitted diseases (STDs) on the development of cervical intraepithelial neoplasia (CIN) has been increasingly recognized over the last 20 years. Much attention has been focused on human papillomavirus (HPV) and the potential for screening for certain HPV types alongside standard cervical cytology in the hope of identifying those females at particular risk of developing high grade CIN or invasive carcinoma. Some infections, for example herpes simplex virus (HSV), have been heavily investigated in the past as they were thought to be involved in the development of CIN but were subsequently discounted. Also discounted as causes of CIN are Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT). These infections were found to be associated with higher rates of CIN in early studies but transpired to be markers for the presence of other infections and pathology and therefore not themselves directly responsible for cytological changes. The role of bacterial vaginosis (BV) is the focus of several current investigations, not only in the genesis of CIN but also in the development of other gynecological and obstetric conditions and complications. Evidence to implicate Trichomonas vaginalis (TV) in the genesis of CIN is conflicting, but there is some evidence that it may exert its influence in a similar way to that hypothesized for BV, ie via abnormal amines. It is well known that there is a high level of concordance of STDs whereby the presence of one infection greatly increases the likelihood of there being one or more others present. There may be a synergism between some infections with regard to the causation of CIN, although the evidence for this is putative. Presented here is an overview of current and previous research in the field of lower genital tract infection as it relates to the development of CIN.

Human papillomavirus (HPV) DNA copy number is dependent on grade of cervical disease and HPV type

The association between human papillomavirus (HPV) DNA copy number and cervical disease was investigated. Viral DNA copy number for the most common high-risk HPV types in cervical cancer (types 16, 18, 31, and 45) was determined in cervical cytobrush specimens from 149 women with high-grade cervical intraepithelial neoplasias (CIN II-CIN III), 176 with low-grade CIN (CIN I), and 270 with normal cytology. Quantitative, PCR-based fluorescent assays for each of the HPV genotypes and for the beta-globin gene were used. The amount of cellular DNA increased significantly with increasing disease; thus, HPV was expressed as copies per microgram of cellular DNA. The assay had a dynamic range of >10(7), allowing documentation for the first time of the wide range of HPV copy numbers seen in clinical specimens. Median HPV DNA copy number varied by more than 10(4) among the viral types. HPV16 was present in the highest copy number; over 55% of HPV16-positive samples contained more than 10(8) copies/microgram. Median copy number for HPV16 showed dramatic increases with increasing epithelial abnormality, an effect not seen with the other HPV types. HPV16 increased from a median of 2.2 x 10(7) in patients with normal cytology, to 4.1 x 10(7) in CIN I patients, to 1.3 x 10(9) copies/microgram in CIN II-III patients. Even when stratified by cervical disease and viral type, the range of viral DNA copies per microgram of cellular DNA was quite large, precluding setting a clinically significant cutoff value for "high" copy numbers predictive of disease. This study suggests that the clinical usefulness of HPV quantitation requires reassessment and is assay dependent.

HPV 16 DNA and mRNA in cervical brush samples quantified by PCR and microwell hybridization

To quantitate HPV 16 DNA and mRNA, biotinylated amplicons from PCR and reverse transcription PCR were captured on streptavidin-coated microtitre plates. The amount of amplicon was determined by colorimetric detection after hybridization with an alkaline phosphatase-labelled probe. Dynamic ranges of between 4 and 6 log10, sufficient to cover the amounts of viral DNA and mRNA prepared from cervical samples were achieved. The reproducibility of the colorimetric detection step was reflected in coefficients of variation (C.V.) below 8%, considerably better than that of chemiluminescence detection. In a series of 89 HPV 16 DNA positive cervical samples, as compared with a CIN I/normal diagnosis subgroup, the number of HPV 16 genome copies per assay was significantly greater in a CIN II subgroup (P = 0.014), and a high-grade neoplasia subgroup (P = 0.040), and the content of HPV 16 mRNA significantly greater in the high-grade neoplasia subgroup (P = 0.0021). The number of mRNA equivalents per copy of viral DNA was higher for E5 than for the other three mRNA species analyzed (P < 0.001), and the concentration of E6*I mRNA was higher than those of the E6 full-length (P < 0.001) and E6*II (P < 0.001) transcripts. Despite these differences, no correlation was found between histological/cytological diagnosis and the amount of viral mRNA relative to the viral load.

A sensitive, type-specific, fluorogenic probe assay for detection of human papillomavirus DNA

A simple method for the detection of a number of human papillomavirus (HPV) genotypes associated with cervical cancer has been developed. The assay exploits the 5'-->3' exonucleolytic activity of Taq DNA polymerase to increase the signal from fluorescent dyes by releasing them from genotype-specific probes during PCR. The probes are oligonucleotides with a 5' reporter dye (6-carboxyfluorescein), a quencher dye (6-carboxy-tetramethyl-rhodamine), and a phosphate-blocked 3' end. In the intact probe, the proximity of the reporter and the quencher results in suppression of reporter fluorescence by Förster-type energy transfer (V. T. Förster. Ann. Phys. 2:55-75, 1948). If the probe is bound downstream of either primer during PCR, the 5'-->3' exonucleolytic activity of Taq polymerase degrades it, allowing the reporter to diffuse away from the quencher, which results in an increase in reporter fluorescence. The increased fluorescence is directly related to the amount of target DNA and can be detected with an automated fluorometer. Probes for the L1 region of the cervical-cancer-associated HPV types 16, 18, 31, 33, and 35 were synthesized and the assays were optimized. The most sensitive assay can detect as few as two copies of HPV DNA in human cervical specimens.

Human papillomaviruses and cervical cancer

Molecular and epidemiological studies conducted over the last 20 years led to the recognition of certain types of human papillomavirus (HPV) as the etiological agents of cervical cancer, a very common neoplasia, particularly in developing countries. More than 70 HPVs have been described, including both cutaneous and mucosal types. About half of the known HPVs, and an even higher number of variants, have been isolated from genital mucosas. The association of certain types primarily with normal tissues and benign lesions, as opposed to cancer-associated types, has led to the concept of low and high oncogenic risk HPVs, respectively. The latter express oncogenic proteins that interfere with cell growth control functions. As a consequence of the continuous expression of these viral genomes, chromosome instability may occur, leading to fully transformed cells. Studies indicate that persistence of high-risk HPVs may determine progression to more severe stages of cervical disease, while the majority of HPV infections are transient and do not seem to be important in cervical carcinogenesis. The risk for disease progression seems also to be associated with viral burden. Prospective epidemiological studies will contribute to the knowledge of the natural history of HPV infections and provide information on the determinants of viral persistence. Data derived from these studies may define the clinical utility of HPV testing and its use in cervical cancer prevention programs.

Clinical role of HPV testing

The subjectivity of morphologic methods contributes to a "swamping" of colposcopic services, excessive costs, overdiagnosis, and overtreatment. HPV DNA testing provides the objectivity required to clarify difficult patient management issues, including follow-up, for low-grade cytologic abnormalities (ASCUS and LSIL), noncorrelating (nonconfirmed) Pap smears, evaluation of nondiagnostic lower genital tract lesions, and cytology and histology laboratory quality assurance. Additionally, favorable preliminary data on HPV testing as a primary screen raise the exciting prospect of potentially lowering costs of cervical cancer-screening programs, while further decreasing the incidence of cervical cancer.

Human papillomavirus-associated oral epithelial dysplasia (koilocytic dysplasia): an entity of unknown biologic potential

Intraepithelial neoplasia of the female genital tract has long been associated with human papillomavirus infection. To date, there have been no previously published studies of oral dysplasia that have identified light microscopic features predictive of the presence of human papillomavirus. We identified a variant of oral epithelial dysplasia, koilocytic dysplasia, that exhibited light microscopic features suggestive of HPV infection. To determine if these microscopic features were specifically correlated with human papillomavirus infection, DNA in situ hybridization for human papillomavirus 6/11, 16/18, and 31/33/51 was performed on 31 lesions diagnosed histologically as koilocytic dysplasia. Seventeen matched control cases of conventional oral epithelial dysplasia were also analyzed for human papillomavirus. Human papillomavirus DNA was detected significantly more often (p < 0.001) in koilocytic dysplasia (80.6%) than conventional oral epithelial dysplasia (0.0%). Positive cases of koilocytic dysplasia contained either intermediate-risk (31/33/51) or high-risk (16/18) human papillomavirus types whether or not they contained low-risk human papillomavirus types (6/11). The histologic and clinical presentation of koilocytic dysplasia was unique. Lesions demonstrated koilocytes and other microscopic characteristics of human papillomavirus infection, as well as features of conventional epithelial dysplasia. A striking male predominance was noted, as was a relatively young average age of presentation (39.0 years). On the basis of our preliminary analysis, we conclude that oral koilocytic dysplasia represents a unique pathologic entity and that the presence of human papillomavirus can be predicted on light microscopy with at least 80% accuracy. The clinical significance and potential for malignant transformation of koilocytic dysplasia remain to be investigated.

A recombinant vaccinia virus encoding human papillomavirus types 16 and 18, E6 and E7 proteins as immunotherapy for cervical cancer

BACKGROUND

Human papillomavirus (HPV) infection, especially with type 16 or 18, is associated with cervical cancer. Two HPV proteins, E6 and E7, are consistently expressed in tumour cells. The objectives of the study were to examine the clinical and environmental safety and immunogenicity in the first clinical trial of a live recombinant vaccinia virus expressing the E6 and E7 proteins of HPV 16 and 18 (TA-HPV).

METHODS

The study was an open label phase I/II trial in eight patients with late stage cervical cancer. The patients were vaccinated with a single dose of TA-HPV and kept in strict isolation to monitor local and systemic side-effects, environmental spread, and anti-E6/E7 immune responses.

FINDINGS

Vaccination resulted in no significant clinical side-effects and there was no environmental contamination by live TA-HPV. Each patient mounted an antivaccinia antibody response and three of the eight patients developed an HPV-specific antibody response that could be ascribed to the vaccination. HPV-specific cytotoxic T lymphocytes, the effector mechanism most likely to be of therapeutic benefit, were detected in one of three evaluable patients.

INTERPRETATION

Further studies to investigate the use ot TA-HPV for immunotherapy of cervical cancer are warranted.

Cervical cancer screening: state of the art

Screening for cervical cancer, the most common form of cancer in women in most developing countries and the second commonest in women in the world as a whole, presents many challenges. Cervical cancer is preventable and it should be a high priority in all national cancer control programmes. It would seem as though, to be highly effective, various methods warrant joint usage, i.e. cytology with virological studies. Their use in both the developed and developing world offer much hope, as does the recent arrival of a physical method for detection.

Epidemiology of cervical intraepithelial neoplasia: the role of human papillomavirus

The evidence implicating specific HPV types in the aetiology of cervical cancer is now strong enough to establish a causative role. HPV infection of the cervix affects the developing immature metaplastic cells of the transformation zone. Cervical neoplasia can be viewed as the interaction of high risk papillomavirus and immature metaplastic epithelium. Once maturity is reached, there is minimal risk of subsequent development of cervical squamous neoplasia. Exposure to HPV is an extremely common event, especially in young sexually active women. Yet, despite frequent HPV exposure at that phase of life in which the cervical transformation zone is at its most vulnerable, established expressed disease is relatively uncommon. Most studies in which the natural history of CIN is not altered by cervical biopsy reveal a progression rate from low to high grade CIN of less than one third. Where viral type is taken into account, however, the progression rate from normal but high risk HPV-infected cervical epithelium to CIN 2 or 3 is higher. Despite this, most cervical abnormalities will not transform into invasive cancer, even if left untreated. The variance between the high rate of HPV infection, the intermediate rate of CIN and the relatively low rate of cervical cancer establishes a stepwise gradient of disease of increasing severity with decreasing prevalence. In an immunocompetent host, HPV infection alone does not appear to be sufficient to induce the step from high grade CIN to invasion. Epidemiological studies indicating that HPV infection with oncogenic viral types is far more common than cervical neoplasia suggest the necessity of cofactors in cervical carcinogenesis. The long time-lag between initial infection and eventual malignant conversion suggests that random events may be necessary for such conversion, and the spontaneous regression of many primary lesions suggests that most patients are not exposed to these random events. Potential cofactors include cigarette smoking, hormonal effects of oral contraceptives and pregnancy, dietary deficiencies, immunosuppression and chronic inflammation. In those women who develop cervical cancer, malignant progression is rarely rapid, more commonly taking many years or decades. Malignant progression has been documented in patients who presented initially with only low grade HPV-induced atypia. On the other hand, progression may be a misnomer, as 'apparent' progression may really represent adjacent 'de novo' development of higher grade CIN. Although most cervical cancers contain high risk HPV types, up to 15% of such cancers test negative for HPV, raising the possibility that a few, usually more aggressive, cervical cancers may arise from from a non-viral source.(ABSTRACT TRUNCATED AT 400 WORDS)

Human papillomavirus testing by hybrid capture appears to be useful in triaging women with a cytologic diagnosis of atypical squamous cells of undetermined significance

OBJECTIVE

Our purpose was to determine the clinical value of human papillomavirus deoxyribonucleic acid testing with the hybrid capture test, specifically to examine whether human papillomavirus testing could identify which women with Papanicolaou smears read as atypical squamous cells of undetermined significance were most likely to have histologically confirmed cervical intraepithelial neoplasia.

STUDY DESIGN

Hybrid capture testing for 14 human papillomavirus types, repeat Papanicolaou smears, and colposcopically directed biopsies were performed concurrently on 217 women referred to a student health colposcopy clinic with a previous Papanicolaou smear read as atypical squamous cells of undetermined significance.

RESULTS

Human papillomavirus deoxyribonucleic acid positivity was associated with an eightfold increased likelihood of histologic confirmation of cervical intraepithelial neoplasia. The sensitivity of hybrid capture for any cervical intraepithelial neoplasia was 86% (43/50) and for grade 2 or 3 was 93% (14/15), whereas the corresponding values for the repeat Papanicolaou smear were 60% (30/50) and 73% (11/15), respectively. Moreover, high viral levels of human papillomavirus types known to be associated with cervical cancer were strongly predictive of high-grade cervical intraepithelial neoplasia.

CONCLUSIONS

Testing for human papillomavirus deoxyribonucleic acid with hybrid capture appears to offer an effective means by which patients whose cervical Papanicolaou smears have been read as atypical squamous cells of undetermined significance could be triaged for colposcopy. In particular, sensitivity for high-grade cervical intraepithelial neoplasia could be maintained and specificity markedly improved by referring only those patients who had elevated levels of human papillomavirus deoxyribonucleic acid of cancer-associated viral types.

Low stringency-PCR (LS-PCR) allows entirely internally standardized DNA quantitation

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Detection of DNA and E7 transcripts of human papillomavirus types 16, 18, 31 and 33, TGF beta and GM-CSF transcripts in cervical cancers and precancers

The association of human papillomavirus (HPV) with a high proportion of cervical cancers should allow the efficiency of cytological screening methods to be improved. We report here that quantitative detection of HPV types 16, 18, 31 and 33 DNA and the corresponding E7 transcripts by polymerase chain reaction (PCR) may be of value in identifying precancers and cancers. In clinical specimens with major cervical lesions, the level of E7 transcription does not appear to be related to concomitant transcription of either transformation growth factor-beta (TGF beta) or granulocyte-macrophage colony stimulating factor (GM-CSF) genes.

Type-specific human papillomavirus DNA in abnormal smears as a predictor of high-grade cervical intraepithelial neoplasia

Human papillomavirus (HPV) typing and quantitation by polymerase chain reaction was performed on exfoliated cells from 133 women referred for colposcopy because of an abnormal smear. High levels of HPV 16 correctly predicted cervical intraepithelial neoplasia (CIN) grade II-III in 93% of its occurrences, but only 59% of cases of CIN III were associated with high levels of this type. Eighty-four per cent of CIN III lesions contained high levels of at least one of HPV types 16, 18, 31, 33 and 35, but the other types were less specific for CIN III than HPV 16. Overall HPV testing compared favourably with cytology for predicting high-grade CIN lesions, but it would appear that some combination of the two modalities will produce better performance than either alone. In particular, HPV testing appears to be helpful in determining which women with mildly abnormal smears have high-grade underlying lesions in need of immediate referral for colposcopy.