Human papillomavirus tests

Diagnostic role of p16/INK4A protein in Human Papillomavirus (HPV) induced cervical dysplasia

The p16/INK4A protein is a cellular regulatory polypeptide over-expressed in the presence of high levels of the Human Papillomavirus (HPV) coded E7 protein. This review outlines the use of p16 antigen staining in cervical biopsies as well as in PAP smears summarizing the corresponding literature and commenting the authors’ own experience. The p16 antigen is a reliable marker for dysplastic cells in CINII/CINIII (HSIL) lesions as viewed in cervical biopsies. When PAP smears were examined at large scale screening for p16 antigenreactive and atypical cells, considerable variations could be found especially in ASCUS graded lesions. Therefore, the presence of p16-reactive atypical cells in PAP smears should be interpreted together with the cytological signs of dysplasia, such as the altered N/C ratio. In addition, women revealing p16-positive ASCUS/LSIL specimens should be examined for the presence of HPV DNA. Detection of HPV DNA alone, i.e. in the absence of cytological screening has a low predictive value, since the clearance of HPV may occur even in the absence of morphological alterations. Combined cytological as well as molecular follow up contributes to the efficiency of diagnostic and increases the probability of correct interpretation of the pre-cancerous lesions by non-invasive techniques.

Human papillomavirus serology and the risk of esophageal and gastric cancers: results from a cohort in a high-risk region in China

Each year, esophageal and gastric cancers cause more than 900,000 deaths worldwide. Human papilloma virus (HPV), especially type 16, has been suggested to have a role in the etiology of esophageal cancer, however, the results of previous seroepidemiological studies have not been consistent. We conducted a large prospective study to examine the association between serum antibodies to HPV 16, HPV 18 and HPV 73 and subsequent development of esophageal squamous cell carcinoma (ESCC), gastric cardia adenocarcinoma (GCA), and gastric noncardia adenocarcinoma (GNCA) in a high-risk population for these cancers in Linxian, China. Case and control subjects for this study were selected from the 29,584 participants of the Linxian General Population Trial. Prediagnostic serum samples from 99 cases of ESCC, 100 cases of GCA, 70 cases of GNCA, and 381 age- and sex- matched controls were selected for this study. The presence of antibodies to HPV virus-like particles was determined by type-specific enzyme-linked immunosorbent assays. Fewer than 15% of ESCC, GCA, or GNCA cases were positive for each HPV type, and no significant associations were found. The adjusted odds ratios (ORs) and 95% confidence intervals (95% CIs) for HPV 16 seropositivity and ESCC, GCA, and GNCA risk were 1.6 (0.8-3.3), 1.3 (0.6-2.8) and 0.4 (0.1-1.6), respectively. The comparable ORs (95% CIs) for HPV 18 were 1.0 (0.4-2.2), 0.9 (0.4-2.1) and 1.5 (0.6-3.4). For HPV 73, these figures were 1.3 (0.6-2.5), 1.2 (0.6-2.3) and 0.9 (0.4-2.1). The results of this study do not support a major role for HPV 16, HPV 18 and HPV 73 in the etiology of esophageal and gastric cancers in Linxian, China.

Quantitation of human papillomavirus 16 E6 and E7 DNA and RNA in residual material from ThinPrep Papanicolaou tests using real-time polymerase chain reaction analysis

BACKGROUND

The detection of specific human papillomavirus 16 (HPV-16) E6 and E7 oncogene transcripts may be a sensitive indicator of the direct involvement of viral oncogenes in the development of cervical neoplasia and carcinoma. The goal of this study was to determine the potential clinical uses of real-time polymerase chain reaction (PCR) and reverse transcription-PCR (RT-PCR) methods for evaluating HPV-16 E6 and E7 oncogene expression.

METHODS

ThinPrep cervical samples were tested for expression of oncogenes of HPV-16 by real-time PCR or RT-PCR analysis and were compared with detection of expression by conventional PCR and RT-PCR analysis. Both sets of results were correlated with the cytologic diagnosis of the cervical samples.

RESULTS

The presence of HPV-16 E6 and E7 DNA and RNA was observed only in HPV-16 positive cervical carcinoma cell lines but not in HPV-18 positive or HPV negative cell lines. The percentage positive for HPV-16 E6 or E7 DNA in a series of ThinPrep cervical cytologic samples (n = 348 samples) was 0% for negative samples (n = 45 samples), 9.7% for atypical squamous cells of undetermined significance (ASCUS; n = 144 samples), 16.9% for low-grade squamous intraepithelial lesion (LSIL; n = 118 samples), and 51.2% for high-grade intraepithelial lesion (HSIL; n = 41 samples). The copy numbers per nanogram for both DNA and RNA E6 and E7 were increased significantly as severity of the lesions progressed from ASCUS to HSIL, and RNA copy numbers were a more sensitive indicator of HPV-16 E6 and E7 expression than DNA copy numbers. The increase in copy numbers took place in a stepwise fashion from ASCUS, to LSIL, to HSIL.

CONCLUSIONS

The detection of HPV-16 E6 and E7 expression by real-time RT-PCR or PCR analysis in ThinPrep cervical cytologic specimens may serve as a quick, reliable, and sensitive tool to identify a subset of patients who express HPV-16 oncoproteins.

Usefulness of human papilloma virus testing in the screening of cervical cancer precursor lesions: a retrospective study in 314 cases

OBJECTIVE

To assess the usefulness of human papilloma virus (HPV) typing for predicting pre-malignant and malignant cervical lesions.

STUDY DESIGN

314 women, who underwent colposcopy, biopsies and high and low-risk HPV typing after a confirmed abnormal routine Pap test were studied. HPV-DNAs were typed by using PCR technique.

RESULTS

We found a significant increasing rate of high-risk-HPV by the increasing severity of histology, ranging from 40% in negative cases to 86.9% in those with CIN3 lesions. The positive predictive value of high-risk-HPV ranged from 13.3% in patients with atypical squamous cells of undetermined significance (ASCUS) to 29.4% in those with HSIL. By contrast, negative predictive value was 96% in patients with ASCUS, 97.2% in low-grade squamous intraepithelial lesions (LSIL), and 71.4% in high-grade squamous intraepithelial lesions (HSIL). Sensitivity and specificity for detecting CIN2 or CIN3 was 86.0% and 41.3%, respectively.

CONCLUSIONS

The high negative predictive value of high-risk HPV testing suggests that HPV negativity could be used for predicting the absence of important cervical lesions, and therefore avoiding unnecessary colposcopy in ASCUS and LSIL cases.

Recent advances in diagnosis and therapy of human papillomaviruses

Infection with human papillomavirus is extremely common throughout the world. Almost 50% of sexually active young women are infected with human papillomavirus and although most infections are transient, a subset has the potential to progress to invasive cancer. During the last 20 years, our understanding of the human papillomavirus life cycle and the role of human papillomavirus in human cancer has dramatically increased. Recent technological advances in human papillomavirus detection have provided the means to detect the presence of human papillomavirus with great sensitivity. In the context of patient care, there is still substantial debate regarding the optimal diagnostic and prognostic use of information derived from hybrid capture or polymerase chain reaction-based detection. The inventory of available treatment options is growing somewhat slowly. The most promising advances are being made in the clinical evaluation of candidates for prophylactic vaccination. This review is focused on the current status and future directions of prevention, diagnosis and therapy.

Comparative evaluation of first- and second-generation digene hybrid capture assays for detection of human papillomaviruses associated with high or intermediate risk for cervical cancer

In the present study we comparatively evaluated the first- and second-generation Digene Hybrid Capture assays for detection of human papillomaviruses (HPV) associated with high or intermediate risk for cervical cancer in cervical specimens. Concordant results were obtained with 468 of 483 (96.8%) specimens. All 15 specimens which gave repeatedly discordant results were positive by the second-generation test only, and 14 of them tested PCR positive. The enhanced sensitivity of the second-generation assay is mainly a result of the reformulation of hybridization reagents and, to a lesser extent, a result of the addition of new HPV probes.

Human papillomavirus deoxyribonucleic acid detection in mildly or moderately dysplastic smears: a possible method for selecting patients for colposcopy

OBJECTIVE

Current screening protocols for cervical cancer dictate that patients with smears read as mild or moderate dysplasia of the uterine cervix undergo colposcopy, although approximately half these women do not prove to have high-grade squamous intraepithelial lesions. The aim of this study was to determine whether human papillomavirus testing is capable of discriminating between high- and low-grade squamous intraepithelial lesions so as to be useful in reducing the number of colposcopic examinations.

STUDY DESIGN

We tested 190 consecutive patients with smears read as mild or moderate dysplasia for the presence of human papillomavirus deoxyribonucleic acid by use of two different polymerase chain reactions with the consensus primer pairs CPI/IIG and MY09/11. Typing was carried out by direct sequence analysis of the CPI/IIG amplimers. The MY09/11 amplimers were detected in enzyme-linked immunosorbent assay format with the SHARP (Solution Hybridization Assay for PCR Products) Signal System with two probe mixtures (A and B) to detect nononcogenic and oncogenic human papillomavirus types. The human papillomavirus test results were compared with the histologic diagnosis, which was regarded as the reference standard.

RESULTS

Fifty-six of the 190 patients had high-grade squamous intraepithelial lesions. The sensitivity was 96% for the CPI/IIG test and 95% for the MY09/11 polymerase chain reaction plus SHARP Signal System when probe B only was used. The specificity was 33% for the CPI/IIG test and 40% for the MY09/11 polymerase chain reaction plus SHARP Signal System when probe B was used.

CONCLUSION

A negative CPI/IIG or SHARP Signal System probe B test can select, respectively, 44 or 54 of the 134 patients without high-grade squamous intraepithelial lesions. The use of these human papillomavirus tests as a secondary triage in patients with smears that were read as mild or moderate dysplasia could prevent those patients from undergoing unnecessary colposcopy. However, respectively, 2 or 3 of the 56 patients who have high-grade squamous intraepithelial lesions would be missed by human papillomavirus testing.

The future of HPV testing in clinical laboratories and applied virology research

BACKGROUND

Human papillomaviruses (HPV) are now considered etiologic agents of cancer of the uterine cervix. Adjunctive diagnostic procedures for the detection of HPV infection could increase the sensitivity of primary and secondary screening of cervical cancer. HPV testing could also improve the specificity of screening programs resulting in avoidance of overtreatment and saving of costs for confirmatory procedures.

OBJECTIVES

To review the rationale of HPV testing in genital diseases and the potential applications of HPV DNA detection methods for clinical and epidemiological purposes.

RESULTS

Progression of HPV infection is associated with the persistence of HPV infection, involvement of high-risk HPV types, high HPV viral load in specimens, integration of viral DNA and possibly the presence of cofactors. The design of HPV diagnostic tests will need to take into account these parameters of disease progression. HPV DNA detection techniques based on signal-amplification are standardized, commercially available and detect several high-risk HPV types. They increase the sensitivity of screening for high-grade and low-grade lesions. Although they may yield false-negative results in the presence of significant HPV-related disease, new test formats could resolve this weakness. Amplification techniques are ideal instruments for epidemiologic purposes since they minimize misclassification of HPV infection status and allow for the detection of low viral burden infections. They are currently not readily applicable to diagnostic laboratories.

CONCLUSIONS

Before recommending HPV testing, prospective trials of untreated LSIL with HPV testing as well as the determination of the efficacy and cost-effectiveness of novel HPV tests, need to be completed.

Diagnosis of human papillomavirus genital tract infection

Although visible anogenital lesions are present in some persons infected with human papillomavirus (HPV), the majority of individuals with HPV genital tract infection do not have clinically apparent disease. Conventional viral detection assays, including serologic assays and growth in cell culture, are not available for the diagnosis and tracking of HPV infection. Papanicolaou tests are a valuable screening tool, but they miss a large proportion of HPV-infected persons. Accordingly, HPV DNA detection assays have become a key research tool in the detection of HPV infection, particularly in asymptomatic individuals. Several types of HPV DNA tests are now available, including Southern blots, dot blots, in situ hybridization, polymerase chain reaction, and solution hybridization (Hybrid Capture assay). Of these, the polymerase chain reaction assay is the most sensitive, whereas dot blots and solution hybridization are the least labor intensive. HPV DNA detection assays are not routinely used in screening patients, in part because the clinical relevance of asymptomatic infection is unclear. Nevertheless, these tests may be beneficial in confirming differential diagnoses and in providing prognostic information, particularly with respect to the HPV type involved.