Accuracy and Reproducibility of Cytology Triage in a HPV-Based Primary Screening Setting: A Revision of 384 Pap Tests

INTRODUCTION

After the transition toward the HPV-based screening protocol, which has led to an increase in sensitivity, and in order to bring the specificity back to acceptable values, cytology underwent a change of approach, becoming a triage test. For these reasons, in the Tuscany region (after the recommendations of the GISCi document), it was decided to reduce, as much as possible, the use of ASC-US category in cytology triage, classifying these morphological cases as negative for intraepithelial lesion or malignancies (NILM) or LSIL, basing on the grade of nuclear atypia. So, in Italy, in a cytology triage context (HPV primary screening), a modified Bethesda system (TBS) is currently used. The aim of this study was to evaluate the performance of the review activity of 384 cytology triage cases and of the cervical cancer screening indicators (sensitivity and specificity for CIN2+ lesions) using the TBS 2014 or the modified TBS.

MATERIALS AND METHODS

384 HPV positive cases at one-year recall (192 with a cytology result of NILM both at baseline and at one-year recall; 192 with a cytology result of NILM at baseline but abnormal at one-year recall), all with a histologically confirmed result (128 CIN2+, 256 ≤ CIN1), were selected, and their baseline Pap tests were reviewed in blind mode by 5 expert cytologists.

RESULTS

The cytological results of NILM were confirmed for 92.5% and 83.8% of cases using TBS 2014 or modified TBS, respectively. 20/128 CIN2+ cases could have been reported at the baseline cytology triage, causing an anticipatory effect and an improvement in sensitivity of the screening protocol at baseline (+15.6%). Using TBS 2014, the number of false positives more than tripled with respect to the modified TBS 2014, with a significant increase in unnecessary colposcopies (+11.4%).

CONCLUSION

This work demonstrated that a greater expertise of cytologists, acquired during the following 3 years of experience with cytological triage, and a strong IQC system could lead to the identification of a significant number of lesions reported to baseline rather than at one-year recall (diagnostic anticipation).

Assessment of the feasibility of pool testing for SARS-CoV-2 infection screening

BACKGROUND

SARS-CoV-2 pandemic represented a huge challenge for national health systems worldwide. Pooling nasopharyngeal (NP) swabs seems to be a promising strategy, saving time and resources, but it could reduce the sensitivity of the RT-PCR and exacerbate samples management in terms of automation and tracing. In this study, taking advantage of the routine implementation of a screening plan on health workers, we evaluated the feasibility of pool testing for SARS-CoV-2 infection diagnosis in the presence of low viral load samples.

METHOD

Pools were prepared with an automated instrument, mixing 4, 6 or 20 NP specimens, including one, two or none positive samples. Ct values of positive samples were on average about 35 for the four genes analyzed.

RESULTS

The overall sensitivity of 4-samples and 6-samples pools was 93.1 and 90.0%, respectively. Focussing on pools including one sample with Ct value ≥35 for all analyzed genes, sensitivity decreased to 77.8 and 75.0% for 4- and 6-samples, respectively; pools including two positive samples, resulted positive in any size as well as pools including positive samples with Ct values <35.

CONCLUSION

Pool testing strategy should account the balance between cost-effectiveness, dilution effect and prevalence of the infection. Our study demonstrated the good performances in terms of sensitivity and saving resources of pool testing mixing 4 or 6 samples, even including low viral load specimens, in a real screening context possibly affected by prevalence fluctuation. In conclusion, pool testing strategy represents an efficient and resources saving surveillance and tracing tool, especially in specific context like schools, even for monitoring changes in prevalence associated to vaccination campaign.

Implementation of a centralized HPV-based cervical cancer screening programme in Tuscany: First round results and comparison with the foregoing Pap-based screening programme

OBJECTIVE

To evaluate performance of the first round of HPV-based screening in Tuscany region and compare it with the prior round of Pap-based screening.

SETTING

Tuscany region of Italy, where HPV-based cervical cancer screening started in 2013, with a strong level of centralization screening tests at the Regional Laboratory for Cancer Prevention (ISPRO).

METHODS

The transition from Pap- to HPV-based screening was initiated for older women and at 3 out of 12 Tuscany Local Health Units (LHUs). Data from the Florence and Grosseto LHUs (about 300,000 women) were analysed and performance screening indicators estimated.

RESULTS

HPV-based indicators recorded good performance, with increased compliance vs. the Pap-based programme. We registered a substantial decrease in waiting times from sampling to test reporting, probably related to the centralization strategy. Since the screening protocol was the same and conducted at a single laboratory, we could hypothesize that the difference in HPV positivity (6.8% in Florence vs. 8.4% in Grosseto) was due to a real difference in HPV prevalence among women of the two LHUs. The transition to HPV-based screening led to a significant increase both in colposcopy referral rate (4.3% vs. 1.2%) and CIN2+ detection rate (8.3‰ vs. 3.4‰).

CONCLUSIONS

HPV-based is more effective in detecting high-grade precancerous and cancerous lesions than Pap-based screening and is characterized by an "anticipatory effect" in the detection of CIN2+ lesions. The transition from Pap-based to HPV-based screening programme should include increased resources dedicated to colposcopy services. Centralization in a laboratory with long experience in this field promotes efficiency of the screening process.

Pool testing on random and natural clusters of individuals: Optimisation of SARS-CoV-2 surveillance in the presence of low viral load samples

Facing the SARS-CoV-2 epidemic requires intensive testing on the population to early identify and isolate infected subjects. During the first emergency phase of the epidemic, RT-qPCR on nasopharyngeal (NP) swabs, which is the most reliable technique to detect ongoing infections, exhibited limitations due to availability of reagents and budget constraints. This stressed the need to develop screening procedures that require fewer resources and are suitable to be extended to larger portions of the population. RT-qPCR on pooled samples from individual NP swabs seems to be a promising technique to improve surveillance. We performed preliminary experimental analyses aimed to investigate the performance of pool testing on samples with low viral load and we evaluated through Monte Carlo (MC) simulations alternative screening protocols based on sample pooling, tailored to contexts characterized by different infection prevalence. We focused on the role of pool size and the opportunity to develop strategies that take advantage of natural clustering structures in the population, e.g. families, school classes, hospital rooms. Despite the use of a limited number of specimens, our results suggest that, while high viral load samples seem to be detectable even in a pool with 29 negative samples, positive specimens with low viral load may be masked by the negative samples, unless smaller pools are used. The results of MC simulations confirm that pool testing is useful in contexts where the infection prevalence is low. The gain of pool testing in saving resources can be very high, and can be optimized by selecting appropriate group sizes. Exploiting natural groups makes the definition of larger pools convenient and potentially overcomes the issue of low viral load samples by increasing the probability of identifying more than one positive in the same pool.

Hybrid capture 2 and cobas® 4800: Comparison of performance of two clinically validated tests for human papillomavirus primary screening of cervical cancer

OBJECTIVE

To compare, in a primary human papillomavirus screening setting, two different validated human papillomavirus tests, considering their analytical and clinical screening performances.

METHODS

In Tuscany, a human papillomavirus screening program was implemented in 2013. Hybrid capture 2 (Qiagen) was used for testing until May 2016, when it was replaced by the cobas^® 4800 human papillomavirus test (Cobas; Roche). We evaluated the performance of Hybrid capture 2 and Cobas on: the same screening population in two different periods (before and after changing to Cobas); the same Hybrid capture 2-positive consecutive samples. Discordant samples (Hybrid capture 2-positive/Cobas negative) were typed on the L1 gene (reverse line blot, AB Analitica) and E6/E7 genes (BD Onclarity assay).

RESULTS

In the considered time period (n = 37,775), human papillomavirus positivity was 9.8% and 7.4%, respectively, for Hybrid capture 2 and Cobas (p < 0.0001). At immediate colposcopy, the cervical intraepithelial neoplasia, grade 2 positive predictive value was, respectively, 23.8% and 34% (p < 0.001). At one-year recall, human papillomavirus persistence was, respectively, 40.6% and 62.2% (p < 0.0001). Of Hybrid capture 2-positive re-tested samples (n = 620), 32.4% were Cobas negative. Of discordant samples typed on L1, 7% were positive for the 12 high-risk human papillomavirus. Of the samples found to be negative for the 12 high-risk human papillomavirus types on L1, 14.5% were positive on E6/E7 typing. Among the discordant samples, the only two cervical intraepithelial neoplasia (CIN) grade 3 lesions were non-high-risk human papillomavirus positive on both L1 and E6/E7 typing.

CONCLUSION

At baseline, Hybrid capture 2 showed greater human papillomavirus positivity and a lower CIN2+ positive predictive value than Cobas, which was more specific than Hybrid capture 2 in detection of high-risk human papillomavirus: 80% of discordant samples were confirmed as high-risk human papillomavirus negative. This higher analytical specificity determined the non-identification of two CIN3 lesions.

HPV infection and pre-neoplastic cervical lesions among 321 HIV+ women in Florence, Italy, 2006-2016: prevalence and associated factors

Women living with HIV (WLWH) are at higher risk for HPV-related malignancies. To estimate the factors associated to HPV infection and to pre-neoplastic cervical lesions, we observed 321 WLWH in an HIV care-centre in Florence, Italy. In 2006-2016, WLWH followed at S. Maria Annunziata Hospital underwent to gynaecological examination including HPV-test, Pap-smear, colposcopy and, if needed, cervical biopsy. Demographical and clinical information were collected and linear logistic regression was performed. Among 321 WLWH, 161 (50.2%) resulted HPV+. Multiple genotypes were identified in 35%, and cancer high-risk genotypes in 61%. Younger age, not-caucasic origin, increasing number of partners, and shorter duration of HIV are associated with HPV infection. A colposcopy was performed in 154 HIV+/HPV+ women: histological lesions were present in 47 (30%). Among these, CIN1, CIN2 and CIN3 were present in 16, 4, and 1 patients, respectively. Being caucasic, smoking 1-20 cigarettes/day, having 2 partners in the last year, and being an injective-drug-user are associated with cervical lesions. The use of bi-valent, 4-valent and 9-valent HPV vaccines would potentially prevent lesions in 19%, 33%, and 48%. Among WLWH efficaciously in care for HIV, demographic and behavioral factors mainly contribute to acquisition of HPV and to development of cervical lesions.

Anoctamin 1 is apically expressed on thyroid follicular cells and contributes to ATP- and calcium-activated iodide efflux

BACKGROUND/AIMS

Iodide efflux from thyroid cells into the follicular lumen is essential for the synthesis of thyroid hormones, however, the pathways mediating this transport have only been partially identified. A calcium-activated pathway of iodide efflux has long been recognized, but its molecular identity unknown. Anoctamin 1 (ANO1) is a calcium-activated chloride channel (CaCC), and this study aims to investigate its contribution to iodide fluxes in thyroid cells.

METHODS

RT-PCR, immunohistochemistry, and live cell imaging with the fluorescent halide biosensor YFP-H148Q/I152L were used to study the expression, localization and function of ANO1 in thyroid cells.

RESULTS

ANO1 mRNA was detected in human thyroid tissue and FRTL-5 thyrocytes, and ANO1 protein was localized to the apical membrane of follicular cells. ATP induced a transient loss of iodide from FRTL-5 cells that was dependent on the mobilization of intracellular calcium, and was inhibited by CaCC/ANO1 inhibitors and siRNA against ANO1. Calcium-activated iodide efflux was also observed in CHO cells over-expressing the Sodium Iodide Symporter (NIS) and ANO1.

CONCLUSION

ANO1 in thyrocytes functions as a calcium-activated channel mediating iodide efflux, and may contribute to the rapid delivery of iodide into the follicular lumen for the synthesis of thyroid hormones following activation by calcium-mobilizing stimuli.

AFM for diagnosis of nanocrystallization of steels in hardening processes

INTRODUCTION

The aim of this study is to investigate the nanocrystallization of steels caused by the transformation from the austenitic to the martensitic phase induced by a severe plastic deformation (SPD) treatment. In this framework, we applied an air blast shot peening treatment, which is a simple protocol widely used for industrial purposes.

METHODS

AISI 286 and AISI 316 specimens were peened for different times and polished using diamond pastes in order to remove corrugations higher than 1 mum. The characterization of the steel surfaces was performed by atomic force microscopy (AFM) operating in contact mode. Additional EDXD measurements were performed to confirm the phase transition.

RESULTS AND DISCUSSION

An AFM-based characterization at nanometric level of the steel surfaces is provided. When the peening exceeds a threshold time that, as expected, depends on the steel composition, a uniform nanostructuration is detected. It is well known that such rearrangement is associated to the growth of a martensitic phase. To date, AFM has been employed in this field only for few applications and to solve specific problems. On the other hand, our results demonstrate that this is a useful technique for the characterization of hardened surfaces, especially when non-destructive sample preparation treatments are required. Moreover, we show that AFM can be a useful tool also for in situ industrial diagnostics of metallic parts.

An AFM investigation of oligonucleotides anchored on unoxidized crystalline silicon surfaces

Carboxylic terminated monolayers have been covalently attached on phosphorous doped crystalline (100) silicon surfaces using a cathodic electro grafting technique. The functionalization concentration and efficiency have been evaluated with different techniques. In particular, topographic images, performed with an atomic force microscope, were used to optimize the protocol in order to obtain a surface whose characteristics of uniformity and reproducibility are ideal for a bio-electronic device. Phase lag images of the functionalized surfaces were also performed, and show non-topographic structures that have been interpreted as areas of different molecule self-orientation. Poly-thymine oligonucleotides have been anchored on such a surface to form a nano-biosensing device capable to react selectively with a specific target molecule, a poly-adenine oligonucleotide. AFM images of high density (approximately 3x10(12) mol/cm2) single strand and double strand covered samples show toroidal shaped structures formed by the self-assembly of the oligonucleotides on the silicon surface.

Roughness of the plasma membrane as an independent morphological parameter to study RBCs: a quantitative atomic force microscopy investigation

A novel approach to the study of RBCs based on the collection of three-dimensional high-resolution AFM images and on the measure of the surface roughness of their plasma membrane is presented. The dependence of the roughness from several parameters of the imaging was investigated and a general rule for a trustful analysis and comparison has been suggested. The roughness of RBCs is a morphology-related parameter which has been shown to be characteristic of the single cells composing a sample, but independent of the overall geometric shape (discocyte or spherocyte) of the erythrocytes, thus providing extra-information with respect to a conventional morphology study. The use of the average roughness value as a label of a whole sample was tested on different kinds of samples. Analyzed data revealed that the quantitative roughness value does not change after treatment of RBCs with various commonly used fixation and staining methods while a drastic decrease occurs when studying cells with membrane-skeletal alteration both naturally occurring or artificially induced by chemical treatments. The present method provides a quantitative and powerful tool for a novel approach to the study of erythrocytes structure through an ultrastructural morphological analysis with the potential to give information, in a non-invasive way, on the RBCs function.

AFM characterization of solid-supported lipid multilayers prepared by spin-coating

Lipids are the principal components of biologically relevant structures as cellular membranes. They have been the subject of many studies due to their biological relevance and their potential applications. Different techniques, such as Langmuir-Blodgett and vesicle-fusion deposition, are available to deposit ordered lipid films on etched surfaces. Recently, a new technique of lipid film deposition has been proposed in which stacks of a small and well-controlled number of bilayers are prepared on a suitable substrate using a spin-coater. We studied the morphological properties of multi-layers made of cationic and neutral lipids (DOTAP and DOPC) and mixtures of them using dynamic mode atomic force microscopy (AFM). After adapting and optimizing, the spin-coating technique to deposit lipids on a chemically etched Silicon (1,0,0) substrate, a morphological nanometer-scale characterization of the aforementioned samples has been provided. The AFM study showed that an initial layer of ordered vesicles is formed and, afterward, depending on details of the spin-coating preparation protocol and to the dimension of the silicon substrate, vesicle fusion and structural rearrangements of the lipid layers may occur. The present data disclose the possibility to control the lipid's structures by acting on spin-coating parameters with promising perspectives for novel applications of lipid films.