Lamin B1 curtails early human papillomavirus infection by safeguarding nuclear compartmentalization and autophagic capacity.

Human papillomavirus (HPV) infection is a primary cause of cervical and head-and-neck cancers. The HPV genome enters the nucleus during mitosis when the nuclear envelope disassembles. Given that lamins maintain nuclear integrity during interphase, we asked to what extent their loss would affect early HPV infection. To address this question, we infected human cervical cancer cells and keratinocytes lacking the major lamins with a HPV16 pseudovirus (HP-PsV) encoding an EGFP reporter. We found that a sustained reduction or complete loss of lamin B1 significantly increased HP-PsV infection rate. A corresponding greater nuclear HP-PsV load in LMNB1 knockout cells was directly related to their prolonged mitotic window and extensive nuclear rupture propensity. Despite the increased HP-PsV presence, EGFP transcript levels remained virtually unchanged, indicating an additional defect in protein turnover. Further investigation revealed that LMNB1 knockout led to a substantial decrease in autophagic capacity, possibly linked to the persistent activation of cGAS by cytoplasmic chromatin exposure. Thus, the attrition of lamin B1 increases nuclear perviousness and attenuates autophagic capacity, creating an environment conducive to unrestrained accumulation of HPV capsids. Our identification of lower lamin B1 levels and nuclear BAF foci in the basal epithelial layer of several human cervix samples suggests that this pathway may contribute to an increased individual susceptibility to HPV infection.

Cells infected with human papilloma pseudovirus display nuclear reorganization and heterogenous infection kinetics.

Human papillomaviruses (HPV) are small, non-enveloped DNA viruses, which upon chronic infection can provoke cervical and head-and-neck cancers. Although the infectious life cycle of HPV has been studied and a vaccine is available for the most prevalent cancer-causing HPV types, there are no antiviral agents to treat infected patients. Hence, there is a need for novel therapeutic entry points and a means to identify them. In this work, we have used high-content microscopy to quantitatively investigate the early phase of HPV infection. Human cervical cancer cells and immortalized keratinocytes were exposed to pseudoviruses (PsV) of the widespread HPV type 16, in which the viral genome was replaced by a pseudogenome encoding a fluorescent reporter protein. Using the fluorescent signal as readout, we measured differences in infection between cell lines, which directly correlated with host cell proliferation rate. Parallel multiparametric analysis of nuclear organization revealed that HPV PsV infection alters nuclear organization and inflates promyelocytic leukemia protein body content, positioning these events at the early stage of HPV infection, upstream of viral replication. Time-resolved analysis revealed a marked heterogeneity in infection kinetics even between two daughter cells, which we attribute to differences in viral load. Consistent with the requirement for mitotic nuclear envelope breakdown, pharmacological inhibition of the cell cycle dramatically blunted infection efficiency. Thus, by systematic image-based single cell analysis, we revealed phenotypic alterations that accompany HPV PsV infection in individual cells, and which may be relevant for therapeutic drug screens.

Confined no more: Viral mechanisms of nuclear entry and egress.

Viruses are obligatory intracellular parasites. For their efficient replication, many require access to the nuclear interior. Yet, only few viral particles are small enough to passively diffuse through the nuclear pore complexes, calling for alternative strategies to bypass the nuclear envelope barrier. Some viruses will await mitotic nuclear envelope breakdown to gain access, whereas others will exploit more active means, for instance by hijacking nuclear pore transport or by directly targeting constituents of the nuclear envelope so as to remodel and temporarily perturb its integrity. After replication, newly produced viral DNA complexes need to cross the same barrier to exit the nucleus and enter the cytoplasm, where the final stages of virion maturation take place. There are also different flavours to the feat of nuclear egress that vary in delicacy and intensity. In this review, we define the major entry and egress strategies that are exploited by different viruses and describe the molecular details thereof. Ultimately, a deeper understanding of these pathways may help identifying molecular targets for blocking viral reproduction or spreading.

Serial measurement of type-specific human papillomavirus load enables classification of cervical intraepithelial neoplasia lesions according to occurring human papillomavirus-induced pathway.

This retrospective study examined whether human papillomavirus (HPV) type-specific viral load changes measured in two or three serial cervical smears are predictive for the natural evolution of HPV infections and correlate with histological grades of cervical intraepithelial neoplasia (CIN), allowing triage of HPV-positive women. A cervical histology database was used to select consecutive women with biopsy-proven CIN in 2012 who had at least two liquid-based cytology samples before the diagnosis of CIN. Before performing cytology, 18 different quantitative PCRs allowed HPV type-specific viral load measurement. Changes in HPV-specific load between measurements were assessed by linear regression, with calculation of coefficient of determination (R) and slope. All infections could be classified into one of five categories: (i) clonal progressing process (R≥0.85; positive slope), (ii) simultaneously occurring clonal progressive and transient infection, (iii) clonal regressing process (R≥0.85; negative slope), (iv) serial transient infection with latency [R<0.85; slopes (two points) between 0.0010 and -0.0010 HPV copies/cell/day], and (v) transient productive infection (R<0.85; slope: ±0.0099 HPV copies/cell/day). Three hundred and seven women with CIN were included; 124 had single-type infections and 183 had multiple HPV types. Only with three consecutive measurements could a clonal process be identified in all CIN3 cases. We could clearly demonstrate clonal regressing lesions with a persistent linear decrease in viral load (R≥0.85; -0.003 HPV copies/cell/day) in all CIN categories. Type-specific viral load increase/decrease in three consecutive measurements enabled classification of CIN lesions in clonal HPV-driven transformation (progression/regression) and nonclonal virion-productive (serial transient/transient) processes.

Linear viral load increase of a single HPV-type in women with multiple HPV infections predicts progression to cervical cancer.

Persistent high-risk human papillomavirus (HPV) infection is strongly associated with development of high-grade cervical intraepithelial neoplasia or cancer (CIN3+). In single type infections, serial type-specific viral-load measurements predict the natural history of the infection. In infections with multiple HPV-types, the individual type-specific viral-load profile could distinguish progressing HPV-infections from regressing infections. A case-cohort natural history study was established using samples from untreated women with multiple HPV-infections who developed CIN3+ (n = 57) or cleared infections (n = 88). Enriched cell pellet from liquid based cytology samples were subjected to a clinically validated real-time qPCR-assay (18 HPV-types). Using serial type-specific viral-load measurements (≥3) we calculated HPV-specific slopes and coefficient of determination (R(2) ) by linear regression. For each woman slopes and R(2) were used to calculate which HPV-induced processes were ongoing (progression, regression, serial transient, transient). In transient infections with multiple HPV-types, each single HPV-type generated similar increasing (0.27copies/cell/day) and decreasing (-0.27copies/cell/day) viral-load slopes. In CIN3+, at least one of the HPV-types had a clonal progressive course (R(2) ≥ 0.85; 0.0025copies/cell/day). In selected CIN3+ cases (n = 6), immunostaining detecting type-specific HPV 16, 31, 33, 58 and 67 RNA showed an even staining in clonal populations (CIN3+), whereas in transient virion-producing infections the RNA-staining was less in the basal layer compared to the upper layer where cells were ready to desquamate and release newly-formed virions. RNA-hybridization patterns matched the calculated ongoing processes measured by R(2) and slope in serial type-specific viral-load measurements preceding the biopsy. In women with multiple HPV-types, serial type-specific viral-load measurements predict the natural history of the different HPV-types and elucidates HPV-genotype attribution.

Detection, genotyping and quantitation of multiple hpv infections in south African women with cervical squamous cell carcinoma.

In Africa, data is limited on quantitation of human papillomavirus (HPV) types in women with multiple infections. This study applied a real time PCR (qPCR) assay for detection, genotyping and quantitation of multiple HPV infections in 90 tissue blocks of South African women with cervical squamous cell carcinoma. One sample with multiple HPV types was subjected to laser micro-dissection and qPCR. Four samples were negative for ß-globin and these were excluded from the analysis. The HPV DNA positivity rate was 93.0% (80/86). All 80 positives showed the presence of HR HPV types; HPV 68 was the only type negative in all the samples. Overall, HPV 16 was positive in most of the samples (88.8%), followed by HPV 56 (28.7%), HPV 18 (20.0%) and HPV 39 (18.7%). More than half of the samples (65.0%) had multiple infections. HPV 16 was present in majority of single (85.7%) and multiple infections (90.4%). HPV 16 showed higher viral loads in 70.3% of the HPV 16 co-infected samples. In one multiple infected sample laser micro-dissection and qPCR identified HPV 18 with higher viral load as the most likely cause of the invasive lesion. There is large number of multiple HPV infections in South African women with cervical squamous cell carcinoma. HPV 16 is the most frequently detected type and often presents with higher viral load, suggesting it could be responsible for pathogenesis of the lesions in the majority of cases.

Serial type-specific human papillomavirus (HPV) load measurement allows differentiation between regressing cervical lesions and serial virion productive transient infections.

Persistent high-risk human papillomavirus (HPV) infection is strongly associated with the development of high-grade cervical intraepithelial neoplasia (CIN) or cancer. Not all persistent infections lead to cancer. Viral load measured at a single time-point is a poor predictor of the natural history of HPV infections. However the profile of viral load evolution over time could distinguish nonprogressive from progressive (carcinogenic) infections. A retrospective natural history study was set up using a Belgian laboratory database including more than 800,000 liquid cytology specimens. All samples were submitted to qPCR identifying E6/E7 genes of 18 HPV types. Viral load changes over time were assessed by the linear regression slope. Database search identified 261 untreated women with persistent type-specific HPV DNA detected (270 infections) in at least three of the last smears for a average period of 3.2 years. Using the coefficient of determination (R²) infections could be subdivided in a latency group (n = 143; R² < 0.85) and a regressing group (n = 127; R² ≥ 0.85). In (≥ 3) serial viral load measurements, serial transient infections with latency is characterized by a nonlinear limited difference in decrease or increase of type-specific viral load (R² < 0.85 and slopes between 2 measurements 0.0010 and -0.0010 HPV copies/cell per day) over a longer period of time (1553 days), whereas regression of a clonal cell population is characterized by a linear (R² ≥ 0.85) decrease (-0.0033 HPV copies/cell per day) over a shorter period of time (708 days; P < 0.001). Using serial HPV type-specific viral load measurements we could for the first time identify regressing CIN2 and CIN3 lesions. Evolution of the viral load is an objective measurable indicator of the natural history of HPV infections and could be used for future triage in HPV-based cervical screening programs.

HPV vaccines to prevent cervical cancer and genital warts: an update.

Cervical cancer is an important public health problem worldwide, and especially in developing countries. The link between cervical cancer and oncogenic human papillomavirus (HPV) infection has been clearly established. Furthermore, non-oncogenic HPV are responsible for the majority of genital warts. Two prophylactic HPV vaccines are available, which have the potential of considerably reducing HPV-related morbidity and mortality. Both vaccines are based on virus-like particles of the L1 capsid protein, and are highly efficacious and immunogenic if given before exposure to HPV, i.e. to adolescent girls between 9 and 13 years of age in a three-dose schedule. This review describes the immunology of natural HPV infections and the immune response evoked through vaccination. The current duration of protection is 8.4 years with the bivalent vaccine (HPV16/18) and 5 years with the quadrivalent vaccine (HPV6/11/16/18). Research is on-going to evaluate the efficacy of the current vaccines in a two-dose schedule, as compared to the recommended three-dose schedule. To increase the protection, the development and testing of a nine-valent prophylactic HPV vaccine (HPV6/11/16/18/31/33/45/52/58) is being undertaken. Research is also directed towards therapeutic vaccines and the development of a prophylactic L2 vaccine.

The TRPM6/EGF pathway is downregulated in a rat model of cisplatin nephrotoxicity.

Cisplatin-induced hypomagnesemia is described in humans and rats, but the underlying mechanisms are still unclear. Recent studies have shown that epidermal growth factor (EGF) stimulates Mg(2+) re-absorption in the distal convoluted tubule via the Mg(2+) channel TRPM6. This study investigates the role of TRPM Mg(2+) channels, claudines, and EGF in the Mg(2+) homeostasis in a rat model of cisplatin-induced nephrotoxicity. Wistar rats were given 2.5 mg/kg cisplatin per week for 3 weeks and were euthanized 4 or 9 weeks after the first administration. The cisplatin treatment significantly increased the fractional excretion of Mg(2+). Real-time RT-PCR and/or Western blots were performed to assess the renal expression TRPM6, TRPM7, claudin-16, claudin-19, EGF, EGF receptor (EGFR) and EGFR-pathway components. The renal mRNA expression of TRPM6 and EGF showed a significant decrease after cisplatin treatment, while the TRPM7, claudin-16 and EGFR expressions remained stable. The claudin-19 mRNA expression was significantly upregulated after cisplatin treatment. Western blotting confirmed the mRNA expression data for the claudins, but an showed upregulation of EGFR only at week 9. The role of the EGFR pathway, involving Pi3-AKT-Rac1, in cisplatin-induced nephropathy, could not be substantiated in further detail. This study shows that cisplatin treatment results in EGF and TRPM6 downregulation in the rat kidney, causing renal Mg(2+) loss. Our results are in line with the hypothesis that EGF influences the renal expression or activation of TRPM6 and plays a significant role in Mg(2+) loss in medication-induced nephropathy.

Changes in type-specific human papillomavirus load predict progression to cervical cancer.

Persistent high-risk human papillomavirus (HPV) infection is strongly associated with the development of high-grade cervical intraepithelial neoplasia or cancer (CIN3+). However, HPV infection is common and usually transient. Viral load measured at a single time-point is a poor predictor of the natural history of HPV infection. The profile of viral load evolution over time could distinguish HPV infections with carcinogenic potential from infections that regress. A case-cohort natural history study was set-up using a Belgian laboratory database processing more than 100,000 liquid cytology specimens annually. All cytology leftovers were submitted to real-time PCR testing identifying E6/E7 genes of 17 HPV types, with viral load expressed as HPV copies/cell. Samples from untreated women who developed CIN3+ (n = 138) and women with transient HPV infection (n = 601) who contributed at least three viral load measurements were studied. Only single-type HPV infections were selected. The changes in viral load over time were assessed by the linear regression slope for the productive and/or clearing phase of infection in women developing CIN3+ and women with transient infection respectively. Transient HPV infections generated similar increasing (0.21 copies/cell/day) and decreasing (-0.28 copies/cell/day) viral load slopes. In HPV infections leading to CIN3+, the viral load increased almost linearly with a slope of 0.0028 copies/cell/day. Difference in slopes between transient infections and infections leading to CIN3+ was highly significant (P < .0001). Serial type-specific viral load measurements predict the natural history of HPV infections and could be used to triage women in HPV-based cervical cancer screening.

Prior knowledge of HPV status improves detection of CIN2+ by cytology screening.

OBJECTIVE: The objective of the study was to investigate whether knowledge of human papillomavirus (HPV) deoxyribonucleic acid test results increases sensitivity of guided cytology screening for the detection of cervical intraepithelial neoplasia (CIN)-2 or higher-grade cervical lesions. STUDY DESIGN: This was a prospective colposcopy-controlled study of 2905 BD SurePath samples to identify cases with CIN2+ within a 24 month follow-up period. Sensitivity and specificity to detect CIN2+ was evaluated, comparing guided cytology screening with and without prior knowledge of HPV status. RESULTS: Prior knowledge of HPV status resulted in significantly higher detection rate of CIN2+ compared with screening blinded to HPV status (P = .005) with limited loss of specificity (P = .026). Gain in sensitivity is higher in older women (43.8%, P = .008) vs in younger women (10.2%, P = .317), whereas loss of specificity is more pronounced in younger women (P < .001) vs older women (P = .729). CONCLUSION: Guided cytological screening performed with prior knowledge of HPV status results in an improved detection of CIN2 or higher-grade lesions.

Expression of renal distal tubule transporters TRPM6 and NCC in a rat model of cyclosporine nephrotoxicity and effect of EGF treatment.

Renal magnesium (Mg(2+)) and sodium (Na(+)) loss are well-known side effects of cyclosporine (CsA) treatment in humans, but the underlying mechanisms still remain unclear. Recently, it was shown that epidermal growth factor (EGF) stimulates Mg(2+) reabsorption in the distal convoluted tubule (DCT) via TRPM6 (Thébault S, Alexander RT, Tiel Groenestege WM, Hoenderop JG, Bindels RJ. J Am Soc Nephrol 20: 78-85, 2009). In the DCT, the final adjustment of renal sodium excretion is regulated by the thiazide-sensitive Na(+)-Cl(-) cotransporter (NCC), which is activated by the renin-angiotensin-aldosterone system (RAAS). The aim of this study was to gain more insight into the molecular mechanisms of CsA-induced hypomagnesemia and hyponatremia. Therefore, the renal expression of TRPM6, TRPM7, EGF, EGF receptor, claudin-16, claudin-19, and the NCC, and the effect of the RAAS on NCC expression, were analyzed in vivo in a rat model of CsA nephrotoxicity. Also, the effect of EGF administration on these parameters was studied. CsA significantly decreased the renal expression of TRPM6, TRPM7, NCC, and EGF, but not that of claudin-16 and claudin-19. Serum aldosterone was significantly lower in CsA-treated rats. In control rats treated with EGF, an increased renal expression of TRPM6 together with a decreased fractional excretion of Mg(2+) (FE Mg(2+)) was demonstrated. EGF did not show this beneficial effect on TRPM6 and FE Mg(2+) in CsA-treated rats. These data suggest that CsA treatment affects Mg(2+) homeostasis via the downregulation of TRPM6 in the DCT. Furthermore, CsA downregulates the NCC in the DCT, associated with an inactivation of the RAAS, resulting in renal sodium loss.

BD-ProExC as adjunct molecular marker for improved detection of CIN2+ after HPV primary screening.

BACKGROUND AND METHODS: We investigated the efficacy of 8 cervical cancer screening strategies relative to cytology with emphasis on immunocytochemical detection of high-risk human papillomavirus (hrHPV)-induced cell transformation (BD-ProExC) as a tool of triage following primary cytology or hrHPV testing. 3,126 women were tested with BD-SurePath liquid-based cytology, hrHPV PCR genotyping and BD-ProExC immunostaining, and colposcopy verification to calculate sensitivity and positive predictive value (PPV) in detecting cervical intraepithelial neoplasia (CIN2(+)). RESULTS: Compared to cytology screening, double testing with cytology and hrHPV resulted in the same sensitivity with a significant increase in the PPV (relative PPV: 1.83). However, twice as many tests were needed. Cytology with atypical squamous cells of undetermined significance (ASC-US) triage and hrHPV testing showed comparative results to double testing requiring only a small increase in number of tests. Screening for hrHPV subtypes 16/18, and ASC-US triage with hrHPV16/18 resulted in significant reductions in sensitivity (ratio: 0.74 and 0.96, respectively). Primary hrHPV/BD-ProExC screening was significantly more sensitive (ratio: 1.63/1.33), but had a significantly lower PPV (ratio: 0.64/0.88). ASC-US triage by BD-ProExC increased the PPV (ratio: 1.90) but decreased the sensitivity (ratio: 0.96). Primary hrHPV screening followed by BD-ProExC triage, led to significant increases in sensitivity (ratio: 1.30) and PPV (ratio: 2.89), and resulted in 55% fewer referrals for colposcopy. CONCLUSIONS: From the investigated screening strategies, primary hrHPV DNA-based screening followed by BD-ProExC triage was determined to be the best screening strategy. IMPACT: Immunocytological triage could be used to perfect hrHPV primary screening.

High-throughput detection, genotyping and quantification of the human papillomavirus using real-time PCR.

BACKGROUND: The establishment of the causal relationship between high-risk human papillomavirus (HR-HPV) infection and cervical cancer and its precursors has resulted in the development of HPV DNA detection systems. Currently, real-time PCR assays for the detection of HPV, such as the RealTime High Risk (HR) HPV assay (Abbott) and the cobas® 4800 HPV Test (Roche Molecular Diagnostics) are commercially available. However, none of them enables the detection and typing of all HR-HPV types in a clinical high-throughput setting. This paper describes the laboratory workflow and the validation of a type-specific real-time quantitative PCR (qPCR) assay for high-throughput HPV detection, genotyping and quantification. This assay is routinely applied in a liquid-based cytology screening setting (700 samples in 24 h) and was used in many epidemiological and clinical studies. METHODS: The TaqMan-based qPCR assay enables the detection of 17 HPV genotypes and ß-globin in seven multiplex reactions. These HPV types include all 12 high-risk types (HPV16, 18, 31, 33, 35, 39, 45, 51, 52, 56, 58, 59), three probably high-risk types (HPV53, 66 and 68), one low-risk type (HPV6) and one undetermined risk type (HPV67). RESULTS: An analytical sensitivity of ≤100 copies was obtained for all the HPV types. The analytical specificity of each primer pair was 100% and an intra- and inter-run variability of <6.4% was observed. CONCLUSIONS: The type-specific real-time PCR approach enables detection of 17 HPV types, identification of the HPV type and determination of the viral load in a single sensitive assay suitable for high-throughput screening.

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.

Stromal issues in cervical cancer: a review of the role and function of basement membrane, stroma, immune response and angiogenesis in cervical cancer development.

The carcinogenesis of cervical carcinoma implies an intricate interplay of neoplastic, human papillomavirus infected epithelial cells and stromal tissue, in which different factors have distinct but interacting influence. Persistent infection with an oncogenic human papillomavirus type may lead to epithelial dysplasia with progressive severity. To access the adjacent stromal tissue, tumour cells have to breach the basement membrane. The stroma partly controls tumour growth, invasion and angiogenesis. Last but not least there is considerable influence of the immune response. In this review we describe the importance of various stromal factors in carcinogenesis of cervical cancer.

Biomarkers in cervical screening: quantitative reverse transcriptase PCR analysis of P16INK4a expression.

Molecular insights into the human papillomavirus (HPV)-induced cervical carcinogenesis led to the discovery of biomarkers for cervical disease. The detection of cellular proteins that are overexpressed by HPV-infected cells, such as tumor suppressor protein p16(INK4a), might play an important role in future cervical cancer screening strategies. P16(INK4a) immunostaining correlates with the severity of cytological and histological abnormalities, but shows some methodological shortcomings such as the lack of standardized methodology and interobserver variability. This study evaluated quantitative reverse transcriptase PCR (RT-PCR) as an alternative tool to analyze p16(INK4a) overexpression as a biomarker for transforming HPV-infections in a liquid-based cervical cytology (LBC) setting. Sixty LBC samples, divided in three groups based on their cytological diagnosis, were subjected to HPV typing and analysis of p16 expression by immunocytochemistry and RT-PCR. The analytical sensitivity of the RT-PCR was determined by spiking HeLa and HaCaT cells. P16(INK4a) expression measured by RT-PCR did not correlate with the cytological diagnosis or HPV status (HPV-positivity, infection type and HPV16-positivity). The spiking experiment proved that, to detect increased biomarker expression by RT-PCR, about 1.0% dysplastic cells is required within a pool of normal keratinocytes. In conclusion, RT-PCR analysis of biomarker expression is not appropriate for cervical screening purposes. In typical LBC samples, the biomarker transcripts of the dysplastic cells are diluted by the RNA of the normal cells in such a manner that their overexpression cannot be detected by RT-PCR.

Human papillomavirus 16 load and E2/E6 ratio in HPV16-positive women: biomarkers for cervical intraepithelial neoplasia >or=2 in a liquid-based cytology setting?

This retrospective case-control study assessed human papillomavirus 16 (HPV16) viral load and E2/E6 ratio as risk markers for cervical intraepithelial neoplasia (CIN) >or=2 lesions in HPV16-positive women in a routine liquid-based cytology setting. Triplex quantitative PCR for HPV16 E6, E2, and beta-globin was done to determine the HPV16 load and the E2/E6 ratio, as a surrogate marker for integration, for women with a negative histologic endpoint (200 controls: 83 normal histology and 117 CIN1) and women with a >or=CIN2 endpoint (180 cases: 41 CIN2, 122 CIN3, and 17 invasive carcinoma). Our analysis showed a significantly higher HPV16 load in the case group, which was completely attributable to the high viral load of samples with invasive carcinoma as histologic endpoint. There was no significant difference in viral load between the other histologic groups. The E2/E6 ratio proved to be lower for the cases. However, the E2/E6 ratio indicated the presence of HPV integration in a considerable amount of control samples (44.3%), which suggests that HPV integration occurs early in the development of cancer and undermines the clinical value of viral integration. Overall, the intrinsic heterogeneous nature of the cervical cytology samples caused a substantial overlap of the HPV16 load and the E2/E6 ratio between controls and cases, which precludes the determination of cutoff values for risk prediction and hampers the clinical applicability in a cervical screening setting.

Quality control for normal liquid-based cytology: rescreening, high-risk HPV targeted reviewing and/or high-risk HPV detection?

The objective of this prospective study was to compare the number of CIN2+cases detected in negative cytology by different quality control (QC) methods. Full rescreening, high-risk (HR) human papillomavirus (HPV)-targeted reviewing and HR HPV detection were compared. Randomly selected negative cytology detected by BD FocalPoint (NFR), by guided screening of the prescreened which needed further review (GS) and by manual screening (MS) was used. A 3-year follow-up period was available. Full rescreening of cytology only detected 23.5% of CIN2+ cases, whereas the cytological rescreening of oncogenic positive slides (high-risk HPV-targeted reviewing) detected 7 of 17 CIN2+ cases (41.2%). Quantitative real-time PCR for 15 oncogenic HPV types detected all CIN2+ cases. Relative sensitivity to detect histological CIN2+ was 0.24 for full rescreening, 0.41 for HR-targeted reviewing and 1.00 for HR HPV detection. In more than half of the reviewed negative cytological preparations associated with histological CIN2+cases no morphologically abnormal cells were detected despite a positive HPV test. The visual cut-off for the detection of abnormal cytology was established at 6.5 HR HPV copies/cell. High-risk HPV detection has a higher yield for detection of CIN2+ cases as compared to manual screening followed by 5% full review, or compared to targeted reviewing of smears positive for oncogenic HPV types, and show diagnostic properties that support its use as a QC procedure in cytologic laboratories.

Immunocytochemistry in liquid-based cervical cytology: analysis of clinical use following a cross-sectional study.

Cytological screening for cervical cancer is hampered by imperfect sensitivity and low inter-observer reproducibility. Human papillomavirus (HPV) testing lacks specificity as a primary screening method. Studies indicate that immunocytochemical detection of alterations caused by HPV in the host cells can optimise screening. Here, the potential of p16(INK4a) (cyclin-dependent kinase inhibitor p16) and MIB-1 (Ki-67 proliferation marker) as adjunct molecular markers for cervical lesions was investigated in a prospective, cross-sectional study of 500 samples in the framework of opportunistic screening in Flanders, Belgium. A consecutive series of 200 samples and 100 samples from the cytological categories ASC, LSIL and HSIL were investigated. Surepath samples were interpreted according to the Bethesda 2001 reporting system. HPV testing was done with MY09/MY11 consensus PCR. Immunocytochemistry for p16(INK4a) and MIB-1 was performed with an automated staining protocol. The number of immunoreactive cells/1,000 cervical cells was assessed. There was a higher mean number of p16(INK4A) and MIB-1 immunoreactive cells/1,000 cells in HSIL (4.06 +/- 1.93 and 11.13 +/- 2.83, respectively) compared to other cytological categories. Both markers showed a large spread in counts, for all categories. In cases of HSIL without immunoreactive cells for either marker, low cellularity and long-term storage in water were often the cause of false negativity. This study confirms that positive staining for p16(INK4a) and MIB-1 is highly correlated with presence of high-grade lesions. These markers could be used as adjuncts to increase the sensitivity of cytological screening as well as the specificity of the HPV test. However, clear methodological standards are needed for optimal performance of immunocytochemistry in a clinical setting.