Recovery of human papillomavirus nucleic acids from liquid-based cytology media

Integrity of RNA in long-term-stored cervical liquid-based cytology samples: implications for biomarker research

Biobanks of cervical screening (LBC) samples annotated with disease status are an invaluable resource to support the development of tools for the risk stratification of disease. Although there is growing interest in the assessment of RNA-based biomarkers, little is known on the suitability and durability of stored clinical samples (commonly used in cervical screening) to support RNA-based research. RNA was extracted from 260 stored LBC samples. Storage at -80°C or -25°C allowed isolation of sufficient RNA for further analysis. RNA was found to be substantially degraded according to Agilent Bioanalyser data. Despite this, RT-qPCR was successful in 95% samples tested. These data suggest that biobanked LBC samples are suitable for RNA-based assessment even if stored for up to 14 years.

Improvement in RNA quantity and quality in cervico-vaginal cytology

The separation of exfoliated cells from the brushes used during cervico-vaginal smears is difficult, a problem which may affect the quality of ribonucleic acid (RNA) extracted. We compared the results of RNA extraction from cervico-vaginal cytology samples according to the type of tubes, preservative solutions, and storage temperature. The samples included exfoliated cervico-vaginal cytological specimens from patients with human papilloma virus 16, positive for cervical intraepithelial neoplasia or cervical cancer. Exfoliated cells were obtained by shaking a brush in a conventional rigid vial tube or squeezing the brush in a soft vial tube. RNA quantity and quality were compared between the two tubes. The concentration and purity of RNA (A260/A280 and A260/A230 ratios) was compared amongst five groups: Group 1, standard frozen storage; Group 2–4, RNA stabilization reagents with room temperature [RNAlater RNA Stabilization Reagent, RNAprotect cell Reagent and AllProtect Tissue Reagent]; and Group 5, Surepath Preservative fluid. To demonstrate the utility of the extracted RNA for PCR-based cDNA synthesis, GAPDH and E6 were targeted and gel band densities of GAPDH and E6 were measured. The median RNA concentration was significantly higher in the soft tubes compared with the rigid tubes (100.2 vs. 7.1 ng/μL, p = 0.0209). The purity of the RNA was higher in soft vial tubes than in rigid vials, as measured by A260/280 and A260/230 ratios. The RNA concentration, purity, and GAPDH density of groups 1, 2 and 3 were significantly higher than those of groups 4 and 5. Moreover, E6 density of group 1 and 2 was significantly higher than that of group 3, 4 and 5. The use of soft tubes enhanced the mRNA quantity and quality in cervico-vaginal cytology. The products of mRNA extraction using RNAlater RNA Stabilization Reagent and RNAprotect Cell Reagent at room temperature were comparable to those obtained by conventional frozen storage. Our protocol improved the yield and quality of RNA and might produce better results for molecular analysis in cervico-vaginal cytology.

PreservCyt Is an Optimal Fixative that Permits Cytologic and Molecular Analyses of Vitreoretinal Lymphoma Biopsies

Purpose: Vitreoretinal lymphoma (VRL) is a potentially fatal intraocular malignancy. Diagnosis is hampered by poor preservation of morphology and DNA/RNA integrity, which precludes adjunctive molecular analysis. We aimed to determine the optimum fixative protocol for VRL biopsies that permits cytology, IHC/flow cytometry and molecular analyses.Methods: Six fixatives were compared on cultured Pfeiffer cells used as a cellular model. Cells were fixed and evaluated on cellular morphology, antibody staining, DNA/RNA amount and integrity. VRL clinical cases were used as validation and proof-of-concept.Results: PreservCyt was the best fixative for preserving cellular morphology and high-quality RNA/DNA from vitreous fluid biopsies. Cells from clinical VRL cases fixed with PreservCyt showed adequate cellular morphology and IHC positivity. Sufficient DNA was obtained for IgH clonality and MYD88 mutation detection using remnant cytological fluid.Conclusions: PreservCyt maintains good morphology and RNA/DNA integrity suggesting that it is a suitable fixative for VRL diagnosis and molecular analysis.

Treatment of first-void urine with Aptima Transfer Solution increases detection of high-risk HPV E6/E7 mRNA

Because of its non-invasive nature urine testing may enable increased screening for HPV in women who avoid cervical sampling. Comparisons have shown fewer HPV positives in urine. The objectives were to compare first-void urine (FVU) treated with proteinase K (PK) to untreated FVU and cervical samples collected from women attending a colposcopy clinic using an Aptima HPV mRNA assay, and comparing the HPV rates to cytology and pathology results. Female FVU (n = 433) was treated with Aptima Transfer Solution (ATS) containing PK within 24 h or after months of storage. Untreated female FVU samples were HPV-positive in 20.8-27.6% compared to 34.4-45.6% of ATS-treated FVU and 44.9-48.4% of PreservCyt samples. Good overall agreement for HR-HPV detection between ATS-FVU and PreservCyt was observed (81.1%; k 0.63). Validation of ATS treatment was performed on 356 male FVU, detecting 6.7% HPV positive compared to 3.4% of untreated samples (p = 0.059). Although HPV presence in ATS FVU and PreservCyt samples were similar, significantly more women with abnormal cervical cytology and histopathology were HPV-positive in cervical specimens than in ATS-treated FVU.

Cervical Cytology Biobanking in Europe

A cervical cytology biobank (CCB) is an extension of current cytopathology laboratory practice consisting in the systematic storage of Pap smears or liquid-based cytology samples from women participating in cervical cancer screening with the explicit purpose to facilitate future scientific research and quality audit of preventive services. A CCB should use an internationally agreed uniform cytology terminology, be integrated in a national or regional screening registry, and be linked to other registries (histology, cancer, vaccination). Legal and ethical principles concerning personal integrity and data safety must be respected strictly. Biobank-based studies require approval of ethical review boards.

A CCB is an almost inexhaustible resource for fundamental and applied biological research. In particular, it can contribute to answering questions on the natural history of HPV infection and HPV-induced lesions and cancers, screening effectiveness, exploration of new biomarkers, and surveillance of the short- and long-term effects of the introduction of HPV vaccination. To understand the limitations of CCB, more studies are needed on the quality of samples in relation to sample type, storage procedures, and duration of storage.

Comparative study of a novel application of automated HR HPV assay and stability in a previously untested Preservative media

BACKGROUND

The suitability and stability of cervical cells in Novaprep media (NHQ) for certain HPV assays is unknown.

METHODS

We evaluated the accuracy of an automated HPV assay (Abbott RealTime HR HPV) for cervical cells prepared in NHQ and NHQ with a pre-treatment to mimic a worst case clinical use, compared to the assay manufacturers media; repeatability and reproducibility of HPV results and the stability of detectable HPV in NHQ over time compared to CE marked liquid based cytology preservatives. Cell lines were used to simulate patient samples.

RESULTS

Cells stored in NHQ produced accurate, repeatable and reproducible results. Stability in NHQ was comparable to the best performing LBC, with at least 7 months' stability at 18-25°C, 2-8°C, -20°C and -80°C; and at least 3 months' stability at 40°C. Similar results were obtained for pre-treated NHQ except only 3.5 months' stability at 18-25°C. Cell line samples in all media and concentrations tested were detected appropriately by the assay.

CONCLUSIONS

Based on this first stage validation analytical study, cervical cells stored in NHQ are suitable for the Realtime HPV assay. There should be no reservations for inclusion of NHQ in any further validation and clinical performance evaluation of this assay.

Performance of the cobas HPV Test for the Triage of Atypical Squamous Cells of Undetermined Significance Cytology in Cervical Specimens Collected in SurePath

OBJECTIVES

Determine performance of the cobas human papillomavirus (HPV) test for triage of atypical squamous cells of undetermined significance (ASC-US) in SurePath.

METHODS

Women presenting for routine screening had cervical specimens collected in SurePath and specimen transport medium (STM); those with ASC-US cytology underwent colposcopy. Performance of cobas HPV in SurePath specimens that had undergone a preanalytic procedure to reverse possible cross-linking of HPV DNA was compared with Hybrid Capture 2 (hc2) specimens in STM.

RESULTS

Among 856 women, HPV prevalence was 45.8%; HPV 16 and HPV 18 prevalences were lower than expected in the 21- to 29-year-old group in this highly vaccinated population. cobas HPV performance in SurePath was comparable to hc2 in STM. Sensitivity and specificity for detection of cervical intraepithelial neoplasia grade 3 or worse were 87.5% (95% confidence interval [CI], 71.9%-95.2%) and 55.5% (95% CI, 52.1%-58.9%) for cobas and 85.3% (95% CI, 69.9%-93.6%) and 54.7% (95% CI, 51.4%-57.9%) for hc2. Sensitivity was negatively affected by random biopsies performed at colposcopy; comparable sensitivities were achieved in the nonvaccinated and vaccinated populations with disease determined by directed biopsy only.

CONCLUSIONS

Performance of cobas HPV for ASC-US triage in pretreated SurePath specimens meets criteria for validation. Preliminary data indicate reliable performance of HPV testing in a highly vaccinated population.

Detection of cervical precancerous lesions with Aptima HPV assays using SurePath preservative fluid specimens

SurePath specimens from women referred to colposcopy were treated with Aptima Transfer Solution (ATS) before testing in Aptima HPV (AHPV) and Aptima HPV 16, 18/45 (AHPV-GT) assays. Untreated SurePath specimens were tested with the cobas HPV test. PreservCyt specimens were assessed for cytology and tested with AHPV. High-grade cervical intraepithelial neoplasia lesions served as the reference standard. Excellent agreement (95.5%; k=0.91) was observed for ATS-treated SurePath specimens between Tigris and Panther systems and between the PreservCyt and ATS-treated SurePath specimens (91.1%, k=0.81) with the AHPV assay on Tigris. Agreement between the AHPV and cobas assays with SurePath specimens was substantial (89.9%, k=0.80). AHPV sensitivity for CIN2+(n=147) was 91.2% for SurePath and PreservCyt. Cobas HPV sensitivity was 93.9% for SurePath specimens. AHPV testing of SurePath specimens was more specific (59.4%) than cobas (54.7%) (p<0.001). Detection and genotyping showed similar absolute and relative risks. ATS-treated SurePath specimens tested with AHPV and AHPV-GT assays showed similar performance with greater specificity than cobas HPV on SurePath specimens. Similar overall results were seen using a CIN3 disease endpoint.

RNA extraction method is crucial for human papillomavirus E6/E7 oncogenes detection

BACKGROUND

Human papillomavirus (HPV) DNA testing plays a main role in the management of cervical cancer, however to improve the specificity in cervical screening, there is a need to develop and validate different approaches that can identify women at risk for progressive disease. Nowadays, mRNA expression of viral E6 and E7 HPV oncogenes stands up as a potential biomarker to improve cervical screening. We aimed to validate a method for RNA extraction, detect HPV mRNA expression and, assess the relationship between E6/E7 mRNA expression and pathology of patients' lesions and progression.

METHODS

This study included 50 specimens that had been previously genotyped as HPV16, 18, 31, 33 and/or 45. Cervical swabs were extracted with three different RNA extraction methods -Nuclisens manual extraction kit (bioMérieux), High Pure Viral RNA Kit (Roche) and RNeasy Plus Mini kit (Qiagen)-, and mRNA was detected with NucliSens EasyQ HPV version 1 test (bioMérieux) afterwards. Association of oncogene expression with pathology and lesion progression was analyzed for each extraction method.

RESULTS

E6/E7 mRNA positivity rate was higher in samples analyzed with bioMérieux (62%), followed by Roche (24%) and Qiagen (6%). Women with lesions and lesion progression showed a higher prevalence of viral RNA expression than women that had not lesions or with lesion persistence. While bioMérieux revealed a higher sensitivity (77.27%), Roche presented a higher PPV (75%) and an increased specificity (89.28%).

CONCLUSIONS

Extraction methods based on magnetic beads provided better RNA yield than those based in columns. Both Nuclisens manual extraction kit (bioMérieux) and High Pure Viral RNA Kit (Roche) seemed to be adequate for E6/E7 mRNA detection. However, none of them revealed both high sensitivity and specificity values. Further studies are needed to obtain and validate a standard gold method for RNA expression detection, to be included as part of the routine cervical screening program.

Development and Validation of a Preanalytic Procedure for Performing the cobas HPV Test in SurePath Preservative Fluid

The formation of chemical cross-links between nucleic acids and proteins in formalin-containing media presents challenges for human papillomavirus (HPV) testing of cervical samples collected in SurePath Preservative Fluid. A preanalytic process involving addition of a nucleophilic buffer and heating the sample to 120°C was developed to reverse the effects of cross-linking and improve nucleic acid accessibility for the cobas HPV Test in SurePath. Cycle threshold (C_T) values for cobas HPV detection were evaluated over time and various temperatures, and mean C_T differences between pretreated and both untreated SurePath samples and those collected in PreservCyt were assessed. Without pretreatment, low viral levels (1 × limit of detection) of HPV were no longer detectable by 7 days. For prospectively collected specimens, mean (95% CI) C_T differences between pretreated and untreated samples indicated enhanced HPV DNA recovery in all categories of treated samples: -2.58 (-3.16 to -2.01), -2.63 (-3.62 to -1.64), and -3.39 (-4.95 to -1.82), respectively, for other 12 high-risk HPV types, HPV16, and HPV18. Furthermore, mean (95% CI) C_T differences of pretreated SurePath samples were comparable to simultaneously collected PreservCyt samples: -0.48 (-0.98 to 0.02) and -0.23 (-0.93 to 0.46), respectively, for HPV16 and HPV18; a borderline significant difference [-0.35 (-0.57 to -0.13)] was observed for other 12 high-risk HPV types. This preanalytic procedure therefore ensures a validated, safe, and accurate method for cobas HPV testing in SurePath.

Cervical Cytology Specimen Stability in Surepath Preservative and Analytical Sensitivity for HPV Testing with the cobas and Hybrid Capture 2 Tests

None of the commercial HPV tests are U.S. FDA-approved for testing of cervical cytology specimens in SurePath preservative. Still, ~30% of HPV testing is performed on specimens in this formalin-containing preservative. Formalin-induced DNA fragmentation and cross-linking may interfere with HPV detection. We evaluated analytical sensitivity and specimen stability of the cobas 4800 HPV (Roche) and Hybrid Capture 2 HPV (HC2, Qiagen) tests with residual cervical cytology samples in SurePath preservative available within 1 week of collection. Cobas testing was performed with and without heating samples at 120°C for 20 min diluted 1:1 in an alkaline environment (pretreatment) to revert DNA crosslinking. Stability was tested after 2 weeks of storage at ambient temperature followed by ≤10 weeks at 4°C. Analytical sensitivity and positivity rates (HC2, 18%; cobas pretreated, 46%; cobas untreated, 47%) were greater for cobas than HC2 (n = 682). After 6 weeks of storage, mean HC2 ratios were lower (mean 0.9, SD 6.3) but high variability limited statistical power to detect trends. Cobas threshold cycles (Ct's) increased in untreated (mean 2.1) but not pretreated samples (mean 0.3; n = 110; p≤0.0001). Overall, cobas had greater analytical sensitivity for samples in SurePath preservative. Although pretreatment introduced a manual sample transfer step and 30 min of incubation times, it improved stability without negatively affecting analytical sensitivity. While awaiting results of large trials to evaluate the clinical performance of cobas, the addition of the pretreatment step may improve the detection of HPV, especially after prolonged sample storage.

Human papillomavirus type 16 L1/L2 DNA methylation shows weak association with cervical disease grade in young women

BACKGROUND

Persistent infection with human papillomavirus (HPV) type 16 causes the majority of cervical cancers. Genital HPV infection is very common, but neoplastic progression is uncommon. There is an urgent need for biomarkers associated with cervical neoplasia, to enable triage of women who test positive for HPV.

OBJECTIVES

To assess the ability of quantitative measurement of HPV16 DNA methylation to separate samples of different cytological and histological grades from young women, among whom rates of HPV infection are high.

STUDY DESIGN

DNA methylation was quantified by pyrosequencing of bisulphite converted DNA from liquid based cytology samples from 234 women (mean age 20.6 years) who tested positive for HPV16 and showed varying degrees of neoplasia. Methylation was assessed at CpGs in the HPV E2 and L1/L2 regions.

RESULTS

The performance of methylation-based classifiers was assessed by ROC curve analyses. The best combination of CpGs (5600 and 5609) achieved AUCs of 0.656 (95% CI=0.520-0.792) for separation of cytologically normal and severely dyskaryotic samples, and 0.639 (95% CI=0.547-0.731) for separation of samples with or without high-grade neoplasia (CIN2+/-).

CONCLUSIONS

The data are consistent with HPV L1/L2 methylation being a marker of the duration of infection in a specific host. Assessment of HPV DNA methylation is hence a promising biomarker to triage HPV-positive cytology samples, but may have limited utility in young women. Future studies assessing the likely utility of HPV DNA methylation as a potential triage biomarker must take account of women's age.

Clinical Performance of Hybrid Capture 2 Human Papillomavirus Testing for Recurrent High-Grade Cervical/Vaginal Intraepithelial Neoplasm in Patients With an ASC-US Papanicolaou Test Result During Long-Term Posttherapy Follow-up Monitoring

Context

Women who have been treated for high-grade cervical or vaginal intraepithelial neoplasia (CIN or VAIN) or invasive carcinoma are at risk for recurrent/persistent disease and require long-term monitoring. The role of human papillomavirus (HPV) testing in this setting is unclear.

Objective

To evaluate the clinical performance of the Hybrid Capture 2 (HC2) HPV test for recurrent/residual high-grade CIN or VAIN in patients with a posttherapy abnormal squamous cells of undetermined significance (ASC-US) Papanicolaou test result.

Design

We reviewed the follow-up data on 100 patients who had an ASC-US Papanicolaou test and HC2 HPV results after treatment for high-grade CIN/VAIN or carcinoma. Human papillomavirus genotyping was performed for women with a negative HC2 result whose follow-up biopsy revealed CIN/VAIN 2+.

Results

The patients' mean age was 47 years. The HC2 test result was positive in 33% of the patients. Follow-up biopsy was available for 17 of these patients (52%) and for 25 of the 67 patients (37%) with a negative HC2 result. A total of 5 of the patients (29%) with a positive HC2 result and 2 of the patients (8%) with a negative HC2 result had CIN/VAIN 3 on follow-up biopsy, a statistically insignificant difference (P = .10). Human papillomavirus 16/18 genotypes were detected in the CIN/VAIN 2+ lesions of 5 patients with a negative HC2 result.

Conclusion

HC2 yielded a false-negative rate of 8% for CIN 3. HC2 testing therefore may not be sufficient for triage of patients with an ASC-US Papanicolaou test result. Patients with ASC-US during long-term posttherapy follow-up need close monitoring, with colposcopic evaluation if clinically indicated.

mRNA biomarker detection in liquid-based cytology: a new approach in the prevention of cervical cancer

Several high-risk human papillomavirus (HPV)-induced cell biomarkers have been proposed as possible candidates to identify patients harboring high-grade squamous intraepithelial lesions (HSILs) of the uterine cervix. We aimed to determine the feasibility of the detection of the mRNA of six biomarkers in cervical smear specimens obtained by liquid-based cytology and to evaluate whether this approach might be useful in the identification of patients with HSIL. One-hundred and twenty three women referred to colposcopy in the Hospital Clinic of Barcelona were included in the study. After a thorough study, including Pap test, high-risk HPV testing (Hybrid Capture 2 test), and colposcopy with directed biopsy and/or endocervical curettage, 48 patients were diagnosed with HSIL, whereas 75 were classified as negative (n=28), or harboring low-grade SIL (n=47). CDKN2A/p16, BIRC5, MMP9, TOP2A, MCM5, and MKI67 mRNA expression was analyzed by reverse transcription quantitative polymerase chain reaction in liquid-based cytology after the Pap test and Hybrid Capture 2 performance. The tissue expression of these biomarkers was analyzed by immunohistochemistry in the biopsy material. One-hundred and thirteen out of 123 (92%) liquid-based cytology yielded adequate material for mRNA analysis. TOP2A was the most sensitive (97%) biomarker for the detection of HSIL and CDKN2A/p16 the most specific (78%). The combination of TOP2A and CDKN2A/p16 showed a sensitivity of 96% (95% confidence interval (CI): 88-99) and a specificity of 71% (95% CI: 55-82). In the immunohistochemistry analysis, all biomarkers showed a high sensitivity but low specificity for HSIL, except CDKN2A/p16 which had a sensitivity of 100% and a specificity of 63%. The combination of TOP2A and CDKN2A/p16 showed a sensitivity of 100% (95% CI: 91-100) and a specificity of 43% (95% CI: 32-55). The detection of mRNA of cell biomarkers in liquid-based cytology material is feasible. The combination TOP2A and CDKN2A/p16 has a good balance between sensitivity and specificity for the detection of women with HSIL.

Evaluation of a new APTIMA specimen collection and transportation kit for high-risk human papillomavirus E6/E7 messenger RNA in cervical and vaginal samples

BACKGROUND

An APTIMA specimen collection and transportation (SCT) kit was developed by Hologic/Gen-Probe.

OBJECTIVES

To compare cervical SCT samples to PreservCyt and SurePath samples and self-collected vaginal samples to physician-collected vaginal and cervical SCT samples. To determine ease and comfort of self-collection with the kit.

STUDY DESIGN

Each woman (n = 580) self-collected a vaginal SCT, then filled out a questionnaire (n = 563) to determine ease and comfort of self-collection. Colposcopy physicians collected a vaginal SCT and cervical PreservCyt, SCT, and SurePath samples. Samples were tested by APTIMA HPV (AHPV) assay.

RESULTS

Agreement between testing of cervical SCT and PreservCyt was 91.1% (κ = 0.82), and that of SurePath samples was 86.7% (κ = 0.72). Agreement of self-collected vaginal SCT to physician-collected SCT was 84.7% (κ = 0.68), and that of self-collected vaginal to cervical SCT was 82.0% (κ = 0.63). For 30 patients with CIN2+, AHPV testing of cervical SCT was 100% sensitive and 59.8% specific compared with PreservCyt (96.6% and 66.2%) and SurePath (93.3% and 70.9%). Vaginal SCT sensitivity was 86.7% for self-collection and 80.0% for physician collection. Most patients found that vaginal self-collection was easy, 5.3% reported some difficulty, and 87.6% expressed no discomfort.

CONCLUSIONS

Cervical samples collected with the new SCT kit compared well to traditional liquid-based samples tested by AHPV. Although there was good agreement between self-collected and physician-collected samples with the SCT, in a limited number of 30 women, vaginal sampling identified fewer with CIN2+ precancerous cervical lesions than cervical SCT sampling. Comfort, ease of use, and detection of high-risk HPV demonstrated that the kit could be used for cervical and vaginal sampling.

Ease and comfort of cervical and vaginal sampling for Chlamydia trachomatis and Trichomonas vaginalis with a new Aptima specimen collection and transportation kit

Use of a new collection kit for vaginal and cervical sampling was reported as easy by the majority of 692 women and not uncomfortable (by 87.4% of those ≥ 25 years old and 78.8% of those <25 years old). By Aptima testing, patient- and physician-collected samples agreed strongly for Chlamydia trachomatis (99.6% to 99.3%; κ = 0.93 to 0.89) and T. vaginalis (99.6% to 98.9%; κ = 0.97 to 0.78).

Understanding HPV tests and their appropriate applications

Greater understanding of the role played by human papillomavirus (HPV) in the causation of disease has led to the development of an increasing number of HPV tests with different characteristics. The bewildering choice facing healthcare professionals and providers is daunting. Clearly, HPV testing is no longer simply of research interest, but can provide information that can be used for individual patient management and at the population level for cervical screening and vaccine surveillance. This review aims to provide the background to the development of HPV tests, to explain the different technologies and to discuss the challenges of the application of these optimally in the varied contexts of disease management. Few HPV tests are approved for clinical use and it is important that clinicians understand which test can be utilized, in what circumstances, with what specimens and the meaning of the report issued. HPV testing is no longer applicable only to cervical disease, and we have suggested additional areas, such as the oropharynx, in which HPV testing services might be implemented in the near future. New tests will continue to emerge and we have identified some of the indirect measures of HPV activity, or biomarkers, that could help in the risk stratification of HPV infection and associated disease. The challenges relating to the optimal application of the various HPV technologies are compounded by the lack of evidence regarding their performance in vaccinated populations. Currently published work, including modelling studies, has been undertaken in non-immunized populations. We therefore end by addressing the issues regarding appropriate strategies and tests for immunized populations.

Prevalence of Human Papillomavirus infection in unselected SurePath samples using the APTIMA HPV mRNA assay

The APTIMA Human Papillomavirus (HPV) Assay detects E6/E7 mRNA from 14 human papillomavirus genotypes. Horizon was a population-based split-sample study among well-screened women, with an aim to compare APTIMA, Hybrid Capture 2 (HC2), and liquid-based cytology (LBC) using SurePath samples. APTIMA testing on the PANTHER platform, and HC2 testing on the Rapid Capture System were performed in accordance with protocols agreed on with the manufacturers before the study, on 5070 consecutive, routine, cervical cytology samples from Copenhagen, Denmark. In this high-risk population, 17% of all samples tested positive on APTIMA, 20% of samples tested positive on HC2, and 7% of samples had abnormal cytology. Among the 4411 samples without recent abnormalities, 15% tested positive on APTIMA, 19% tested positive on HC2, and 5% had abnormal cytology. The κ coefficient of 0.75 suggested substantial agreement between APTIMA and HC2. This is the first APTIMA study using SurePath samples on the PANTHER platform. The trends in positivity rates on SurePath samples for APTIMA, HC2, and LBC were consistent with studies based on PreservCyt samples, and the agreement between the two HPV assays was substantial. The high proportions of women testing positive suggest that in countries with a high HPV prevalence, caution will be needed if HPV tests, including mRNA-based tests, are to replace LBC.

Long-term stability of human genomic and human papillomavirus DNA stored in BD SurePath and Hologic PreservCyt liquid-based cytology media

We evaluated the effect of storage at 2 to 8°C on the stability of human genomic and human papillomavirus (HPV) DNA stored in BD SurePath and Hologic PreservCyt liquid-based cytology media. DNA retained the ability to be extracted and PCR amplified for more than 2.5 years in both medium types. Prior inability to detect DNA in archived specimens may have been due to failure of the extraction method to isolate DNA from fixed cells.

An evaluation of the Shandon Papspin liquid-based oral test using a novel cytologic scoring system

OBJECTIVES

The aim of this study was to evaluate a cost-effective oral liquid-based cytology screening test, Shandon Papspin (PS).

STUDY DESIGN

We compared the diagnostic accuracy of PS with surgical biopsy in 69 patients. Transepithelial cytology specimens were obtained with the use of cervical cytobrushes. Cytology specimens were graded and scored by using a novel oral cytologic grading and scoring system.

RESULTS

Histologic diagnosis of dysplasia or malignancy was made in 51/69 cases, and cytology identified 49/51 cases, with a sensitivity of 96% and specificity of 100%. The best cutoff value for distinguishing reactive/mildly dysplastic lesions from high grade/invasive squamous cell carcinoma was determined to be a cytologic score of 3, representing a sensitivity of 95% and specificity of 96%.

CONCLUSIONS

PS appears to be an accurate and economical test for detection of high-risk dysplasias and cancers, but the real significance of this method will be its diagnostic accuracy in studies focusing strictly on lesions with a low level of clinical concern.

Follow-up outcomes of a large cohort of low-risk women with negative imaged liquid-based cytology and negative HPV test results

Recently updated cervical screening guidelines have proposed a 5-year screening interval for women aged 30 years and older with "double-negative" Papanicolaou (Pap) and high-risk human papillomavirus (hrHPV) results (DNR); however, published US follow-up data on women with DNR tested with US Food and Drug Administration (FDA) - approved HPV testing are limited to studies from Kaiser Permanente using conventional Pap smear cytology. Between July 2005 and June 2006, 4,112 patients with DNR who were screened with computer-imaged liquid-based cytology (LBC) (ThinPrep) and Hybrid Capture 2 (HC2) hrHPV tests of LBC vial fluid were identified. Cytologic or histopathologic data were available for 3,211 patients who were followed up for a mean 44 months. Among 2,960 patients aged 30 years and older with DNR, follow-up cervical abnormalities of cervical intraepithelial neoplasia (CIN) 3 or more severe (CIN3+) were documented in 5 (0.17%), including 1 endocervical adenocarcinoma. After DNR, CIN+ diagnoses were significantly more likely in women younger than 50 years than in older women. These data are consistent with previously published US and international studies that have consistently documented low rates of histopathologic CIN3+ during years of follow-up after DNR. Large-scale nationwide data are needed to further assess the level of risk of invasive cervical cancer after DNR using different available hrHPV testing methods.

Limitations of widely used high-risk human papillomavirus laboratory-developed testing in cervical cancer screening

OBJECTIVE

To increase awareness of the limitations of high-risk human papillomavirus (hrHPV) laboratory-developed testing (LDT) widely used in US cervical cancer screening.

METHODS AND RESULTS

A young woman in her 30s was diagnosed and treated for stage 1B1 cervical squamous cell carcinoma in which HPV 16 DNA was detected using polymerase chain reaction testing. Both 1 month before and 42 months before cervical cancer diagnosis, the patient had highly abnormal cytology findings; however, residual SurePath™ (Becton, Dickson and Company, Franklin Lakes, NJ) vial fluid yielded negative Hybrid Capture 2 (HC2; Qiagen NV, Hilden, Germany) hrHPV LDT results from each of the two specimens. This prompted questions to be asked concerning the performance characteristics of hrHPV LDT. A review of the available data indicates that (1) purification of DNA from SurePath specimens requires complex sample preparation due to formaldehyde crosslinking of proteins and nucleic acids, (2) HC2-SurePath hrHPV testing had not been Food and Drug Administration-approved after multiple premarket approval submissions, (3) detectible hrHPV DNA in the SurePath vial decreases over time, and (4) US laboratories performing HC2-SurePath hrHPV LDT testing are not using a standardized manufacturer-endorsed procedure.

CONCLUSION

Recently updated cervical screening guidelines in the US recommend against the use of hrHPV LDT in cervical screening, including widely used HC2 testing from the SurePath vial. The manufacturer recently issued a technical bulletin specifically warning that use of SurePath samples with the HC2 hrHPV test may provide false negative results and potentially compromise patient safety. Co-collection using a Food and Drug Administration-approved hrHPV test medium is recommended for HPV testing of patients undergoing cervical screening using SurePath samples.

Follow-up outcomes in a large cohort of patients with human papillomavirus-negative ASC-H cervical screening test results

Limited follow-up data are available on patients with cervical cytology results of atypical squamous cells, cannot exclude a high-grade intraepithelial lesion (ASC-H), who test negative for high-risk human papillomavirus (hrHPV). Between June 2005 and December 2010, 885 patients were identified with ThinPrep results of Hybrid Capture 2 (HC2) hrHPV-negative cervical ASC-H liquid-based cytology and follow-up histopathology or cytology results extending to September 2011. Of the 885 patients with available follow-up results, 549 (62.0%) had at least 1 histopathologic result during the entire follow-up period, whereas 336 (38.0%) had only cytologic follow-up documented. In an average follow-up period of 29 months, 14 (1.6%) of 885 patients with HPV-negative ASC-H results showed evidence of high-grade cervical intraepithelial neoplasia (CIN2/3). No cases of invasive cervical cancer were diagnosed. Four of 14 patients with HPV-negative ASC-H results with follow-up diagnoses of CIN2/3 had a history of earlier CIN2/3 diagnoses before HPV-negative ASC-H results. Follow-up of patients with HPV-negative ASC-H results using methods specified in this study yielded low rates of detectible CIN2/3 and no diagnoses of cervical cancer. Triage of study patients with HPV-negative ASC-H results to routine HPV and cytology cotesting at 1 year was a safe follow-up option.

Screening test results associated with cancer diagnoses in 287 women with cervical squamous cell carcinoma

CONTEXT

The limitations of newer cervical screening tests are still being studied.

OBJECTIVE

To investigate those limitations, we conducted a retrospective review of 287 cases of cervical squamous cell carcinoma (SCC).

DESIGN

A search through 5 years of records identified 287 women with cervical SCC diagnoses. Clinical history, histopathology, and liquid-based cytology (ThinPrep) and Hybrid Capture 2 (HC2) high-risk human papillomavirus (HPV) results were documented. Polymerase chain reaction HPV tests were performed on SCC tissues with prior negative HC2 results.

RESULTS

Of 287 women, 156 (54.4%) had abnormal cytology results, and 75 (26.1%) had abnormal clinical findings triggering tissue diagnoses of SCC. Among 156 patients with abnormal Papanicolaou (Pap) test results, more-seriously abnormal Pap test results were reported in 142 women (91.1%). Among 31 women with Pap and HC2 HPV cotesting within 1 year of SCC diagnoses, 28 (90%) were Pap⁺/HPV⁺, 2 (15.5%) were Pap⁺/HPV⁻, and 1 (3%) was Pap⁻/HPV⁻. Two of 3 women with negative HC2 results before SCC diagnosis had abnormal Pap results; 1 had negative Pap reports with questionable lesional cells mimicking atrophy. In all 3 cases of SCC with negative HC2 results, HPV-18 was detected; in 2 cases (66%), HPV-16 was also detected.

CONCLUSIONS

Although abnormal cytology preceded most SCC diagnoses, about one-third of patients were referred for diagnostic testing because of clinical suspicion alone. Among 31 SCC cases with liquid-based cytology and high-risk HPV cotest results less than 1 year before SCC diagnoses, 2 patients (6.5%) had Pap⁺/HPV⁻ results, and 1 patient (3.2%) had Pap⁻/HPV⁻ results. Polymerase chain reaction detected high-risk HPV DNA in tumor tissues of 3 SCC cases with recent HC2⁻ results.

Diverse mechanisms of growth inhibition by luteolin, resveratrol, and quercetin in MIA PaCa-2 cells: a comparative glucose tracer study with the fatty acid synthase inhibitor C75

The rationale of this dose matching/dose escalating study was to compare a panel of flavonoids-luteolin, resveratrol, and quercetin-against the metabolite flux-controlling properties of a synthetic targeted fatty acid synthase inhibitor drug C75 on multiple macromolecule synthesis pathways in pancreatic tumor cells using [1,2-(13)C(2)]-d-glucose as the single precursor metabolic tracer. MIA PaCa-2 pancreatic adenocarcinoma cells were cultured for 48 h in the presence of 0.1% DMSO (control), or 50 or 100 μM of each test compound, while intracellular glycogen, RNA ribose, palmitate and cholesterol as well as extra cellular (13)CO(2), lactate and glutamate production patterns were measured using gas chromatography/mass spectrometry (GC/MS) and stable isotope-based dynamic metabolic profiling (SiDMAP). The use of 50% [1,2-(13)C(2)]-d-glucose as tracer resulted in an average of 24 excess (13)CO(2) molecules for each 1,000 CO(2) molecule in the culture media, which was decreased by 29 and 33% (P < 0.01) with 100 μM C75 and luteolin treatments, respectively. Extracellular tracer glucose-derived (13)C-labeled lactate fractions (Σm) were between 45.52 and 47.49% in all cultures with a molar ratio of 2.47% M + 1/Σm lactate produced indirectly by direct oxidation of glucose in the pentose cycle in control cultures; treatment with 100 μM C75 and luteolin decreased this figure to 1.80 and 1.67%. The tracer glucose-derived (13)C labeled fraction (Σm) of ribonucleotide ribose was 34.73% in controls, which was decreased to 20.58 and 8.45% with C75, 16.15 and 6.86% with luteolin, 27.66 and 19.25% with resveratrol, and 30.09 and 25.67% with quercetin, respectively. Luteolin effectively decreased nucleotide precursor synthesis pentose cycle flux primarily via the oxidative branch, where we observed a 41.74% flux (M + 1/Σm) in control cells, in comparison with only a 37.19%, 32.74%, or a 26.57%, 25.47% M + 1/Σm flux (P < 0.001) after 50 or 100 μM C75 or luteolin treatment. Intracellular de novo fatty acid palmitate (C16:0) synthesis was severely and equally blocked by C75 and luteolin treatments indicated by the 5.49% (control), 2.29 or 2.47% (C75) and 2.21 or 2.73% (luteolin) tracer glucose-derived (13)C-labeled fractions, respectively. On the other hand there was a significant 192 and 159% (P < 0.001), and a 103 and 117% (P < 0.01) increase in tracer glucose-derived cholesterol after C75 or luteolin treatment. Only resveratrol and quercetin at 100 μM inhibited tracer glucose-derived glycogen labeling (Σm) and turnover by 34.8 and 23.8%, respectively. The flavonoid luteolin possesses equal efficacy to inhibit fatty acid palmitate de novo synthesis as well as nucleotide RNA ribose turnover via the oxidative branch of the pentose cycle in comparison with the targeted fatty acid synthase inhibitor synthetic compound C75. Luteolin is also effective in stringently controlling glucose entry and anaplerosis in the TCA cycle, while it promotes less glucose flux towards cholesterol synthesis than that of C75. In contrast, quercetin and resveratrol inhibit glycogen synthesis and turnover as their underlying mechanism of controlling tumor cell proliferation. Therefore the flavonoid luteolin controls fatty and nucleic acid syntheses as well as energy production with pharmacological strength, which can be explored as a non-toxic natural treatment modality for pancreatic cancer.

Cervical cytology biobanks as a resource for molecular epidemiology

A cervical cytology biobank (CCB) is an extension of current cytopathology laboratory practice consisting in the systematic storage of Pap smears or liquid-based cytology samples from women participating in cervical cancer screening with the explicit purpose of facilitating future scientific research and quality audit of preventive services. A CCB should use an internationally agreed uniform cytology terminology, be integrated in a national or regional screening registry, and linked to other registries (histology, cancer, and vaccination). Legal and ethical principles concerning personal integrity and data safety must be respected strictly. Biobank-based studies require approval from ethical review boards. A CCB constitutes a nearly inexhaustible resource to perform fundamental and applied biologic research. In particular, it can contribute in answering questions on the natural history of HPV infection and HPV-induced lesions and cancers, screening effectiveness, exploration of new biomarkers, and surveillance of short- and long-term effects of the introduction of HPV vaccination. To understand the limitations of CCB, more studies are needed on quality of samples in relation to sample type, storage procedures, and duration of storage.

APTIMA assay on SurePath liquid-based cervical samples compared to endocervical swab samples facilitated by a real time database

Background:

Liquid-based cytology (LBC) cervical samples are increasingly being used to test for pathogens, including: HPV, Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) using nucleic acid amplification tests. Several reports have shown the accuracy of such testing on ThinPrep (TP) LBC samples. Fewer studies have evaluated SurePath (SP) LBC samples, which utilize a different specimen preservative. This study was undertaken to assess the performance of the Aptima Combo 2 Assay (AC2) for CT and GC on SP versus endocervical swab samples in our laboratory.

Materials and Methods:

The live pathology database of Montefiore Medical Center was searched for patients with AC2 endocervical swab specimens and SP Paps taken the same day. SP samples from CT-and/or GC-positive endocervical swab patients and randomly selected negative patients were studied. In each case, 1.5 ml of the residual SP vial sample, which was in SP preservative and stored at room temperature, was transferred within seven days of collection to APTIMA specimen transfer tubes without any sample or patient identifiers. Blind testing with the AC2 assay was performed on the Tigris DTS System (Gen-probe, San Diego, CA). Finalized SP results were compared with the previously reported endocervical swab results for the entire group and separately for patients 25 years and younger and patients over 25 years.

Results:

SP specimens from 300 patients were tested. This included 181 swab CT-positive, 12 swab GC-positive, 7 CT and GC positive and 100 randomly selected swab CT and GC negative patients. Using the endocervical swab results as the patient’s infection status, AC2 assay of the SP samples showed: CT sensitivity 89.3%, CT specificity 100.0%; GC sensitivity and specificity 100.0%. CT sensitivity for patients 25 years or younger was 93.1%, versus 80.7% for patients over 25 years, a statistically significant difference (P = 0.02).

Conclusions:

Our results show that AC2 assay of 1.5 ml SP samples transferred to APTIMA specimen transfer medium within seven days is sufficiently sensitive and specific to be used to screen for CT and GC. CT sensitivity may be somewhat reduced in samples from patients over 25 years. SP specimens retained in the original SP fixative for longer time intervals also may have decreased sensitivity, due to deterioration of RNA, but this was not assessed in this study. The ability to tap the live pathology database is a valuable tool that can useful to conduct clinical studies without a costly prospective clinical trial.

Nucleic acid sequence-based amplification assay for human papillomavirus mRNA detection and typing: evidence for DNA amplification

Human papillomavirus (HPV) E6/E7 mRNA has been proposed as a more specific marker for cervical dysplasia and cancer than HPV DNA. This study evaluated the RNA specificity of nucleic acid sequence-based amplification (NASBA)-based HPV detection using HPV DNA plasmids (HPV type 16 [HPV16], HPV18, HPV31, HPV33, and HPV45) and nucleic acid extracts of several cell lines, which were systematically subjected to enzymatic treatments with DNase and RNase. HPV plasmid dilutions (10(6) to 10(0) copies/microl) and nucleic acid extracts (total DNA, RNA-free DNA, total RNA, and DNA-free RNA) of unfixed and fixed (PreServCyt and SurePath) HaCaT, HeLa, and CaSki cells were tested with the NucliSENS EasyQ HPV test. The RNA-free DNA extracts of HeLa and CaSki cells could be amplified by HPV18 and -16 NASBA, respectively. Fixation of the cells did not influence NASBA. All HPV plasmids could be detected with NASBA. Based on the plasmid dilution series, a lower detection limit of 5 x 10(3) HPV DNA copies could be determined. Our study identified viral double-stranded DNA as a possible target for NASBA-based HPV detection. The differences in diagnostic accuracy between the NASBA-based tests and conventional HPV DNA detection assays seem to be attributable not to the more specific amplification of viral mRNA but to the limited type range and the lower analytical sensitivity for HPV DNA.

Validation of the APTIMA Combo 2 assay for the detection of Chlamydia trachomatis and Neisseria gonorrhoeae in SurePath liquid-based pap test samples taken with different collection devices

Mocked samples of Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (GC) diluted in SurePath liquid-based Pap (L-Pap) fluid were detected by the APTIMA Combo 2 assay to end points 10-fold greater than dilutions in specimen transport media. Pooled L-Pap clinical specimens yielded CT-positive results after storage at room temperature for 10 days. Based on an infected patient standard for comparison, cervical swabs, urine, and SurePath L-Pap test samples collected with a SurePath cervical broom or ThinPrep cytobrush from 520 women then tested by APTIMA Combo 2 assay, detected 25 (4.8%) with CT, 5 (1.0%) with (GC), and 3 (0.6%) with both. Percent sensitivities (80-84), specificities (99.8-100), positive (99.5-100) and negative (99.2-99) predictive values of SurePath L-Pap for CT were validated as similar to those reported in a previously published multicenter trial. All values for GC were 100%. One collection device was not significantly better than the other.

Single valproic acid treatment inhibits glycogen and RNA ribose turnover while disrupting glucose-derived cholesterol synthesis in liver as revealed by the [U-C(6)]-d-glucose tracer in mice

Previous genetic and proteomic studies identified altered activity of various enzymes such as those of fatty acid metabolism and glycogen synthesis after a single toxic dose of valproic acid (VPA) in rats. In this study, we demonstrate the effect of VPA on metabolite synthesis flux rates and the possible use of abnormal (13)C labeled glucose-derived metabolites in plasma or urine as early markers of toxicity. Female CD-1 mice were injected subcutaneously with saline or 600 mg/kg) VPA. Twelve hours later, the mice were injected with an intraperitoneal load of 1 g/kg [U-(13)C]-d-glucose. (13)C isotopomers of glycogen glucose and RNA ribose in liver, kidney and brain tissue, as well as glucose disposal via cholesterol and glucose in the plasma and urine were determined. The levels of all of the positional (13)C isotopomers of glucose were similar in plasma, suggesting that a single VPA dose does not disturb glucose absorption, uptake or hepatic glucose metabolism. Three-hour urine samples showed an increase in the injected tracer indicating a decreased glucose re-absorption via kidney tubules. (13)C labeled glucose deposited as liver glycogen or as ribose of RNA were decreased by VPA treatment; incorporation of (13)C via acetyl-CoA into plasma cholesterol was significantly lower at 60 min. The severe decreases in glucose-derived carbon flux into plasma and kidney-bound cholesterol, liver glycogen and RNA ribose synthesis, as well as decreased glucose re-absorption and an increased disposal via urine all serve as early flux markers of VPA-induced adverse metabolic effects in the host.

Isolation of RNA from cell lines and cervical cytology specimens stored in BD SurePath preservative fluid and downstream detection of housekeeping gene and HPV E6 expression using real time RT-PCR

This study was performed to demonstrate that RNA isolated from cell lines and cervical cytology specimens stored in SurePath preservative fluid would be functional in real-time RT-PCR assays. RNA was isolated from cervical cell lines or cytology samples stored in SurePath preservative at room temperature for 2-5 weeks using five commercially available RNA purification kits, three of which contain proteinases. The quality of the RNA was assessed by real time RT-PCR amplification of GAPDH, GUSB, U1A, HPV 16 and 18 E6 mRNAs. RNA was isolated successfully from cells that were stored in SurePath preservative fluid with only the three protocols that contained proteinases. GAPDH was amplified in 98-100% of the samples, GUSB in 90-98%, and the least abundant transcript, U1A, was amplified in 81-96% of the samples. HPV 16 and 18 E6 transcripts were detected in 56% of high grade, 39% of low grade and 2% of normal samples, with a concordance between DNA genotype and E6 mRNA expression of 97%. We demonstrated that RNA can be extracted from cervical cell lines and cytology specimens stored in BD SurePath preservative fluid with three different procedures that all contain proteinases. This RNA is suitable for real-time RT-PCR applications.

New technologies in cervical cancer screening

A shift to a molecular approach to cervical cancer screening is the most likely solution to the goals of improved screening in both the developed and developing world. The impetus for new screening technologies in the developed world is predominately driven by the need to increase positive predictive value and reduce over-management of low-grade and often transient abnormalities (i.e., increase specificity). Rapid tests, where results can be given to a patient within the same visit, are anticipated to have the greatest impact in low resource settings in low and middle income countries (and in disadvantaged sub-populations in high-income countries) where substantial loss to follow up cripples the effectiveness of cervical cancer screening programs. Clinical validation will be required before these tests are implemented in routine screening programs.

Human papillomavirus mRNA and p16 detection as biomarkers for the improved diagnosis of cervical neoplasia

Human papillomavirus (HPV) infection of the genital tract is very common and normally follows a benign clinical course; however, in an unfortunate minority of infected individuals, it can cause disease that sometimes leads to cancer. It is accepted that HPV DNA testing has a role in the management of cervical disease both in a prevaccination and postvaccination era; however, to improve the specificity of this approach, there is a requirement to develop and validate tools/assays that can identify women at risk for progressive disease. There is evidence to suggest that detection of viral gene expression both directly and indirectly may constitute a more specific approach for delineating clinically significant infection compared with HPV DNA-based assays. HPV oncogene expression and evidence of its deregulation can be monitored through direct detection of viral mRNA transcripts or through detection of the cellular protein p16. For both approaches, commercial assays have been introduced and numerous studies have been conducted. The present article describes the scientific theory underpinning these approaches, their amenability to routine-diagnostic specimens/settings, and the clinical data that has been garnered through their application thus far. Currently, there is promising data indicating that HPV mRNA and p16 might play an important role in future cervical cancer screening scenarios. Still, large randomized studies are necessary to confirm the preliminary data.

METHODS

PubMed and OVID were interrogated with search terms "HPV RNA;" "HPV mRNA;" "HPV transcript-detection, testing, and methods;" "p16" AND "cervical cancer;" "p16" AND "CIN;" "p16" AND "histology"; "p16" AND "cytology;" "p16;" and "screening."

Human papillomavirus in cervical cancer screening: important role as biomarker

Cervical cytology screening has reduced cervical cancer morbidity and mortality but shows important shortcomings in terms of sensitivity and specificity. Infection with distinct types of human papillomavirus (HPV) is the primary etiologic factor in cervical carcinogenesis. This causal relationship has been exploited for the development of molecular technologies for viral detection to overcome limitations linked to cytologic cervical screening. HPV testing has been suggested for primary screening, triage of equivocal Pap smears or low-grade lesions and follow-up after treatment for cervical intraepithelial neoplasia. Determination of HPV genotype, viral load, integration status and RNA expression could further improve the effectiveness of HPV-based screening and triage strategies. The prospect of prophylactic HPV vaccination stresses the importance of modification of the current cytology-based screening approach.