P16INK4a immunohistochemistry improves the reproducibility of the histological diagnosis of cervical intraepithelial neoplasia in cone biopsies

Utility of p16INK4a expression for the interpretation of uterine cervical biopsies in Kenya

Introduction

histologic interpretation of hematoxylin and eosin-stained cervical biopsies is subject to substantial discordance among pathologists. Immunohistochemical staining for p16INK4a can reduce inter-observer disagreement. We did a cross-sectional study to evaluate the utility of p16INK4a staining in the assessment of cervical biopsies in Nairobi, Kenya.

Methods

hematoxylin and eosin-stained sections from 91 colposcopic biopsies diagnosed as negative for dysplasia or as cervical intraepithelial neoplasia (CIN) grade 1-3 from 2011-2013 in Nairobi, Kenya, were reviewed and immunostained for p16INK4a. Agreement in interpretation of cervical biopsies was compared between primary and consensus review results.

Results

on primary evaluation, 16 cases were negative for squamous dysplasia; 23 were CIN 1; 37 CIN 2; and 15 CIN 3. On consensus review, 32 cases were negative for dysplasia; 19 were CIN 1; 16 CIN 2 and 24 CIN 3. Agreement was moderate between primary and consensus histology review results for the diagnosis of low-grade versus high-grade squamous intraepithelial lesions (Kappa = 0.568). None of the cases negative for dysplasia were positive for p16INK4a expression, but in primary and consensus review results, 17% and 5% cases of CIN 1; 49% and 69% of CIN 2, and 80% and 96% of CIN 3 were p16INK4a positive, respectively.

Conclusion

there was significant variability in the interpretation of cervical biopsies on hematoxylin and eosin between primary and consensus review assessments. 75% of CIN 1 cases that were upgraded to CIN 2 during consensus review expressed p16INK4a. These findings demonstrate the role of p16INK4a in increasing diagnostic accuracy and as a marker of high-grade CIN 2/3.

Expression of P63, P16 and CK17 in Atypical Squamous Metaplasia and Cervical Intraepithelial Neoplasia

Background & Objective:

Cervical intraepithelial neoplasia (CIN) is a dysmaturation process in squamous cells in epithelial layer, which highly increases the risk of developing cervical cancer. The aim of this study was to compare the expression of three biomarkers, p16, p63, and CK17 in patients with CIN and in those with atypical squamous metaplasia (ASM).

Methods:

In this study, 100 patients underwent a colposcopy-guided cervix biopsy. Immunostaining for the biomarkers was undertaken on tissue samples presented with ASM (n=50) and CIN (n=50).

Results:

A significant increase in immunostaining for CK7, P63, and P16 in patients with CIN was found compared to ASM subjects.

Conclusion:

Expression of CK17, P63, and P16 in CIN varied from those in ASM. Those biomarkers could be reliable factors to distinguish ASM from CIN; however, all the biomarkers could differentiate CIN from its mimics due to their high degree of sensitivity and specificity.

Cytologic-Histologic Discrepancies in Pathology of the Uterine Cervix: Analysis of the Clinical and Pathologic Factors

Cytologic-histologic correlation (CHC) represents a documented effort to obtain and compare, when available, gynecologic cytology reports with an interpretation of high-grade squamous intraepithelial lesion or malignancy, with the subsequent histopathology report, and to determine the possible cause of any discrepancy. The correlation is influenced by multiple closely interdependent clinical and pathologic factors. Many of these factors including the sensitivity and accuracy of colposcopy-directed biopsy, the diligence of the colposcopist, and the attributes of the cervical lesion represent "preanalytical" factors which can significantly affect the CHC outcome, but are often less emphasized during CHC process. The status of "gold standard" of cervical biopsy histology will be less "golden" if clinicians miss, during colposcopy, the lesion which had been flagged by cytology. CHC also serves as one of the important assurance tools to monitor and improve the pathology laboratory overall quality, and the ability of the pathologists to enhance their diagnostic interpretation. As pathologists, we should make every effort to improve on CHC, by applying systematic approaches, both in technical laboratory and interpretive diagnosis, which increase yield and reduce diagnostic discrepancies. The widespread use of Human Papilloma Virus testing and p16 immunohistochemistry have significantly enhanced diagnostic accuracy both in cytology and in histology. Herein, we review the intimate relationships and factors that may govern discrepancies between cytology, colposcopy-directed biopsies, and biopsies with subsequent Loop Electroexcision Procedure for cervical squamous intraepithelial lesions. Ultimately the projected risk for high-grade squamous intraepithelial lesion and cancer and the suggested management guidelines are directly tied in with effective CHC.

[Modern biomarkers for precancerous lesions of the uterine cervix : Histological-cytological correlation and use]

The correlation between the cytological findings from the PAP smear and the histological outcome in cases where the cytological findings must be histologically verified, is an integral component of the German screening program for cervical cancer. These data are collected nationwide as part of a benchmarking process by the individual Associations of Statutory Health Insurance Physicians (KV) in the federal states and reported to the National Association of Statutory Health Insurance Physicians (KBV) in Berlin. In most cases there is a good correlation between cytology and histology but in some cases either a different grade of severity of cervical intraepithelial neoplasia (CIN) is found or the histological findings are negative. The reasons for a lack of correlation can be insufficient sampling in the cytology or the biopsy or a misinterpretation of the individual findings. Although the findings from H&E sections are considered to be the gold standard in the histological evaluation, it has long been known that the interobserver agreement in these preparations is only moderate. A significant improvement becomes apparent, firstly by the classification of cervical cancer precursors into low-grade and high-grade groups and secondly by the targeted application of biomarkers, in particular p16 and Ki-67, according to the recommendations of the lower anogenital squamous terminology standardization (LAST) project. The biomarkers p16 and Ki-67 should be used in the differential diagnostics between reactive and reparative alterations and for further differentiation of a CIN grade 2 but not to confirm a CIN grade 3. It is still unclear whether p16 is suitable as a prognostic marker for low-grade lesions.

Performance of p16INK4a ELISA as a primary cervical cancer screening test among a large cohort of HIV-infected women in western Kenya: a 2-year cross-sectional study

OBJECTIVE

A biomarker with increased specificity for cervical dysplasia compared with human papillomavirus (HPV) testing would be an attractive option for cervical cancer screening among HIV-infected women in resource-limited settings. p16(INK4a) has been explored as a biomarker for screening in general populations.

DESIGN

A 2-year cross-sectional study.

SETTING

2 large HIV primary care clinics in western Kenya.

PARTICIPANTS

1054 HIV-infected women in western Kenya undergoing cervical cancer screening as part of routine HIV care from October 2010 to November 2012.

INTERVENTIONS

Participants underwent p16(INK4a) specimen collection and colposcopy. Lesions with unsatisfactory colposcopy or suspicious for cervical intraepithelial neoplasia 2+ (CIN2+; including CIN2/3 or invasive cervical cancer) were biopsied. Following biopsy, disease status was determined by histopathological diagnosis.

PRIMARY AND SECONDARY OUTCOME MEASURES

We measured the sensitivity, specificity and predictive values of p16(INK4a) ELISA for CIN2+ detection among HIV-infected women and compared them to the test characteristics of current screening methods used in general as well as HIV-infected populations.

RESULTS

Average p16(INK4a) concentration in cervical samples was 37.4 U/mL. After colposcopically directed biopsy, 127 (12%) women were determined to have CIN2+. Receiver operating characteristic analysis showed an area under the curve of 0.664 for p16(INK4a) to detect biopsy-proven CIN2+. At a p16(INK4a) cut-off level of 9 U/mL, sensitivity, specificity, positive and negative predictive values were 89.0%, 22.9%, 13.6% and 93.8%, respectively. The overall p16(INK4a) positivity at a cut-off level of 9 U/mL was 828 (78.6%) women. There were 325 (30.8%) cases of correct p16(INK4a) prediction to detect or rule out CIN2+, and 729 (69.2%) cases of incorrect p16(INK4a) prediction.

CONCLUSIONS

p16(INK4a) ELISA did not perform well as a screening test for CIN2+ detection among HIV-infected women due to low specificity. Our study contributes to the ongoing search for a more specific alternative to HPV testing for CIN2+ detection.

Sparteine as an anticonvulsant drug: Evidence and possible mechanism of action

Sparteine is a quinolizidine alkaloid extracted from Lupinus that has numerous pharmacological properties both in humans and animal models. In the central nervous system, sparteine reduces locomotor activity, has light analgesic effects, also has no effects on short-term memory or spatial learning and does not induce changes in behavior or electroencephalographic (EEG) activity. However, the anticonvulsant profile of sparteine is not fully characterized in experimental animals and there are no data in humans. Therefore, the present review focuses on the experimental evidence supporting the anticonvulsant action of sparteine in models of acute seizures and status epilepticus (SE), as well as its possible mechanisms of action. The evidence that supports the anticonvulsant effect of (-)-Sparteine sulfate includes the inhibition of seizures induced by maximal electro-stimulation, a delay in the onset of convulsive behavior and the prolongation of survival time in mice treated with pentylenetetrazole (PTZ). Additionally, sparteine delays the onset of convulsive behavior and decreases the severity and mortality of rats treated with PTZ and pilocarpine. Sparteine decreases amplitude and frequency or blocks the epileptiform activity induced by PTZ, pilocarpine and kainic acid. Sparteine may decrease hyperexcitability through the activation of the M2 and M4 subtypes of mAChRs, which is a probable mechanism of action that together with its systemic effects may favor its anticonvulsant effects against seizures and SE.

Novel p16 binding peptide development for p16-overexpressing cancer cell detection using phage display

Protein p(16INK4a) (p16) is a well-known biomarker for diagnosis of human papillomavirus (HPV) related cancers. In this work, we identify novel p16 binding peptides by using phage display selection method. A random heptamer phage display library was screened on purified recombinant p16 protein-coated plates to elute only the bound phages from p16 surfaces. Binding affinity of the bound phages was compared with each other by enzyme-linked immunosorbent assay (ELISA), fluorescence imaging technique, and bioinformatic computations. Binding specificity and binding selectivity of the best candidate phage-displayed p16 binding peptide were evaluated by peptide blocking experiment in competition with p16 monoclonal antibody and fluorescence imaging technique, respectively. Five candidate phage-displayed peptides were isolated from the phage display selection method. All candidate p16 binding phages show better binding affinity than wild-type phage in ELISA test, but only three of them can discriminate p16-overexpressing cancer cell, CaSki, from normal uterine fibroblast cell, HUF, with relative fluorescence intensities from 2.6 to 4.2-fold greater than those of wild-type phage. Bioinformatic results indicate that peptide 'Ser-His-Ser-Leu-Leu-Ser-Ser' binds to p16 molecule with the best binding score and does not interfere with the common protein functions of p16. Peptide blocking experiment shows that the phage-displayed peptide 'Ser-His-Ser-Leu-Leu-Ser-Ser' can conceal p16 from monoclonal antibody interaction. This phage clone also selectively interacts with the p16 positive cell lines, and thus, it can be applied for p16-overexpressing cell detection.

p16INK4a immunohistochemistry in cervical biopsy specimens: A systematic review and meta-analysis of the interobserver agreement

OBJECTIVES

The interpretation of cervical biopsy specimens guides management of women with suspected cervical cancer precursors. However, morphologic evaluation is subjective and has low interobserver agreement. Addition of p16(INK4a) immunohistochemistry may improve interpretation.

METHODS

We performed a systematic review and meta-analysis of published data on interobserver agreement of p16(INK4a) positivity using p16(INK4a) immunohistochemistry and of cervical intraepithelial neoplasia grade 2 (CIN2+) and CIN grade 3 (CIN3+) classification using H&E morphology in conjunction with p16(INK4a) in comparison with H&E morphology alone.

RESULTS

The literature search revealed five eligible articles. The results show strong agreement of pathologists' interpretation of cervical biopsy specimens as p16(INK4a) positive or negative (pooled κ = 0.90; 95% confidence interval [CI], 0.88-0.92) and significantly higher agreement for a CIN2+ diagnosis with H&E morphology in conjunction with p16(INK4a) (κ = 0.73; 95% CI, 0.67-0.79) compared with H&E morphology alone (κ = 0.41; 95% CI, 0.17-0.65). Also, a slightly higher agreement for CIN3+ can be observed (κ = 0.66; 95% CI, 0.39-0.94 for H&E morphology in conjunction with p16(INK4a) and κ = 0.61; 95% CI, 0.44-0.78 for H&E morphology alone), but this difference was not statistically significant.

CONCLUSIONS

The published literature indicates improved interobserver agreement of the diagnosis of CIN2+ with the conjunctive use of H&E morphology with p16(INK4a) immunohistochemistry compared with H&E morphology alone.

Impact of p16(INK4a) immunohistochemistry staining on interobserver agreement on the diagnosis of cervical intraepithelial neoplasia

OBJECTIVES

This study aimed to compare the interobserver Cohen κ on H&E staining and on H&E plus p16(INK4a) staining of all cervical biopsy specimens in a population-based screening program.

METHODS

All the colposcopy-guided biopsies generated by the routine screening of 23,258 women aged 25 to 64 years were stained with H&E and H&E plus p16. Biopsy specimens were reviewed by six external experts.

RESULTS

The four diagnoses were available in 441 cases. The interobserver κ values were 0.52 (95% confidence interval [CI], 0.45-0.58) and 0.48 (95% CI, 0.42-0.56) with H&E and H&E + p16, respectively, when using a five-group classification (normal, CIN 1, CIN 2, CIN 3, and cancer); adopting a two-group classification (≤CIN 1 and ≥CIN 2), the values were 0.75 (95% CI, 0.66-0.82) and 0.70 (95% CI, 0.61-0.79), respectively.

CONCLUSIONS

The use of p16 on all cervical biopsy specimens in a screening program showed virtually no effect on reproducibility of the histologic diagnosis.

Variability of Pathologists' Utilization of p16 and Ki-67 Immunostaining in the Diagnosis of Cervical Biopsies in Routine Pathology Practice and Its Impact on the Frequencies of Cervical Intraepithelial Neoplasia Diagnoses and Cytohistologic Correlations

Context.—The use of p16 in cervical biopsies improves the accuracy of cervical intraepithelial neoplasia (CIN) diagnosis and grading and decreases its interpathologist variability.

Objective.—To determine the impact of the frequency of use of p16 immunostains in cervical biopsies on pathologists' diagnoses of CIN grade 1 and grade 2 or above (CIN1 and CIN2+) and on cytohistologic correlations.

Design.—We identified all cervical biopsy specimens with cytologic correlations subjected or not to p16 staining from January 1, 2005, to September 30, 2010; calculated each pathologist's percentage of p16 use; and correlated it with their major cytohistologic discrepancy rates, CIN2+ diagnoses, and CIN1/CIN2+ ratios.

Results.—During the study period, each of the 23 pathologists interpreted 59 to 1811 (mean, 518) of 11 850 cervical biopsy specimens, used p16 for 0% to 21.31% (mean, 10.14%) of these, had CIN2+ detection rates of 9.5% to 24.1% (mean, 18.9%), and CIN1/CIN2+ ratios of 0.7 to 4.5 (mean, 1.5). Compared to the 12 “low users” of p16, who used p16 fewer times than the institution's mean for p16 use, the 11 “high users” of p16 diagnosed more biopsies (8391 versus 3459), had a lower rate of major cytohistologic discrepancies (12.62% versus 14.92%, P < .001), a higher rate of CIN2+ diagnoses (19.9% versus 16.4%, P < .001), a lower range of CIN2+ rates (15.0%–23.1% versus 9.5%–24.1%), and lower CIN1/CIN2+ ratios (1.2 versus 2.3).

Conclusions.—We found a high intrainstitutional variability of p16 use in cervical biopsies, CIN2+ rates, and CIN1/CIN2+ ratios. Use of p16 for greater than 10% of cervical biopsies was associated with improved cytohistologic correlation rates and with lower variability in the frequencies of histologic diagnoses.

p16 is superior to ProEx C in identifying high-grade squamous intraepithelial lesions (HSIL) of the anal canal

Although the incidence of human papillomavirus (HPV)-associated anal neoplasia is increasing, interobserver and intraobserver reproducibility in the grading of biopsy specimens from this area remains unacceptably low. Attempts to produce a more reproducible grading scheme have led to the use of biomarkers for the detection of high-risk HPV (HR-HPV). We evaluated the performance of standard morphology and biomarkers p16, ProEx C, and Ki-67 in a set of 75 lesions [17 nondysplastic lesions, 23 low-grade squamous intraepithelial lesions (LSIL)/condyloma, 20 high-grade squamous intraepithelial lesions (HSIL), 15 invasive squamous cell carcinomas] from the anal and perianal region in 65 patients and correlated these findings with HPV subtype on the basis of a type-specific multiplex real-time polymerase chain reaction assay designed to detect HR-HPV. A subset of cases with amplifiable HPV DNA was also sequenced. HSIL was typically flat (15/20), and only a minority (4/20) had koilocytes. In contrast, only 1 LSIL was flat (1/23), and the remainder were exophytic. The majority of LSIL had areas of koilocytic change (20/23). HR-HPV DNA was detected in the majority (89%) of invasive carcinomas and HSIL biopsies, 86% and 97% of which were accurately labeled by strong and diffuse block-positive p16 and ProEx C, respectively. LSIL cases, however, only infrequently harbored HR-HPV (13%); most harbored low-risk HPV (LR-HPV) types 6 and 11. Within the LSIL group, p16 outperformed ProEx C, resulting in fewer false-positive cases (5% vs. 75%). Ki-67 was also increased in HR-HPV-positive lesions, although biopsies with increased inflammation and reactive changes also showed higher Ki-67 indices. These data suggest that strong and diffuse block-positive nuclear and cytoplasmic labeling with p16 is a highly specific biomarker for the presence of HR-HPV in anal biopsies and that this finding correlates with high-grade lesions.

Reproducibility of endocervical curettage diagnoses

OBJECTIVE

To estimate overall interobserver variability of histopathology diagnoses on endocervical curettage (ECC) specimens.

METHODS

Five study pathologists, blinded to the original diagnosis, reviewed archived ECC specimens initially interpreted as normal, low-grade dysplasia, and high-grade dysplasia. We assessed interobserver agreement and agreement between pathologists using the κ statistic and analyzed the effect of reducing diagnostic choices to two categories (one method using "normal and dysplasia" and another method using "normal and low-grade" and "high-grade or worse").

RESULTS

A total of 90 specimens were reviewed. The overall observer agreement was moderate (κ = 0.52). For specific diagnoses, cases interpreted as normal or high-grade dysplasia demonstrated greater agreement than those interpreted as low-grade dysplasia. Individual pathologists' comparison κ values ranged from 0.31 to 0.80. Changing diagnostic options to a two-tiered system resulted in significant improvement in κ values for only 1 of 36 pathologist comparisons. Using the gynecologist pathologist consensus interpretation, study pathologists downgraded 44% of cases originally interpreted as high-grade.

CONCLUSION

Interobserver agreement in the interpretation of ECC specimens is at best moderate, even between those with additional experience and training in gynecologic pathology. Furthermore, reducing diagnostic options to two categories did not improve agreement. It is concerning that important clinical decisions may be made based on an ECC diagnosis that is moderately or poorly reproducible.

LEVEL OF EVIDENCE

II.

The natural history of human papillomavirus infections of the mucosal epithelia

Human papillomaviruses (HPVs), members of a very large family of small DNA viruses, cause both benign papillomas and malignant tumors. While most research on these viruses over the past 30 years has focused on their oncogenic properties in the genital tract, they also play an important role in diseases of the upper aerodigestive tract. Rapidly accelerating advances in knowledge have increased our understanding of the biology of these viruses and this knowledge, in turn, is being applied to new approaches to prevent, diagnose, and treat HPV-induced diseases. In this introductory article, we provide an overview of the structure and life cycle of the mucosal HPVs and their interactions with their target tissues and cells. Finally, we provide our thoughts about treatments for HPV-induced diseases, present and future.

Conjunctive p16INK4a testing significantly increases accuracy in diagnosing high-grade cervical intraepithelial neoplasia

The histopathologic interpretation of cervical intraepithelial neoplasia (CIN) is subject to a high level of interobserver variability and a substantial number of false-positive and false-negative results. We assessed the impact of the conjunctive interpretation of p16(INK4a)-immunostained slides on the accuracy of community-based pathologists in diagnosing high-grade cervical intraepithelial neoplasia (CIN; CIN 2 and CIN 3) in biopsy specimens. Twelve pathologists rendered independent diagnoses on a set of 500 H&E-stained cervical punch and conization specimens. Results were compared with a dichotomized "gold standard" established by consensus of 3 gynecopathology experts. When p16(INK4a)-immunostained slides were added and conjunctively interpreted with the H&E-stained slides, a significant increase in diagnostic accuracy for the detection of high-grade CIN was observed (P = .0004). Sensitivity for high-grade CIN was increased by 13%, cutting the rate of false-negative results in half. Agreement of community-based pathologists in diagnosing high-grade CIN was significantly improved (mean kappa values advanced from 0.566 to 0.749; P < .0001). Reproducibility of p16(INK4a) stain interpretation was excellent (kappa = 0.899). Our results show that conjunctive interpretation of p16(INK4a)-stained slides could significantly improve the routine interpretation of cervical histopathology.

Topical treatment of CIN 2+ by cidofovir: results of a phase II, double-blind, prospective, placebo-controlled study

OBJECTIVE

Randomized controlled trial evaluating a topical treatment for cervical intraepithelial neoplasia 2 and 3 (CIN 2+) using cidofovir.

METHODS

Fifty-three women with a biopsy-proven CIN 2+ were randomly assigned, 6 weeks before their planned conisation, either 3 applications of 3 ml 2% cidofovir in Intrasite gel in a cervical cap or a placebo (the same volume of Intrasite alone). A cervical sample for high-risk types of human papillomaviruses (HPV) (Hybrid Capture 2 or HC2) was taken before treatment and before conisation. The cone was submitted for pathological examination, and subsequently, along with the initial biopsy, to in situ hybridization (ISH) for high-risk HPV.

RESULTS

Forty-eight patients were treated and followed according to the protocol, (23 cidofovir, and 25 placebo). Fourteen of the 23 cones were free of any CIN (60.8%) in the cidofovir group. Only 5 of 25 cones were free of any CIN (20%) in the placebo group (p<0.01). The difference remained significant in the ITT group (p<0.05). In the per-protocol and ITT populations, we observed more frequent viral clearance in the cidofovir group, but the difference was significant only when evaluated by ISH and not by HC2. No systemic toxicity was observed. Cervico-vaginal side effects of cidofovir were limited, and not statistically different from placebo.

CONCLUSION

The medical topical treatment with cidofovir, at this point, cannot replace conisation, but it is a promising candidate for topical chemotherapy of CIN 2+ lesions; a larger prospective randomized study is needed to confirm our results.

Colposcopy to evaluate abnormal cervical cytology in 2008

The rates of cervical cancer in the United States are low in comparison with developing nations. Whereas the Papanicolaou smear has performed well in terms of detecting both precursors of squamous cell carcinoma and squamous cell carcinoma of the cervix, this test has been less successful at identifying those women with the highest-risk premalignant disease. The use of human papillomavirus testing has also contributed to the improved sensitivity of screening for cervical cancer. In light of this, the colposcopy clinic retains high referral rates yet has poor diagnostic accuracy. Unfortunately, patients are triaged to follow-up for abnormal Papanicolaou smears based on algorithms that rely on the less evidence-based techniques of colposcopy. Therefore, the need to improve the specificity of colposcopic-guided biopsy remains. The colposcopic procedure is highlighted in this review and evaluated in terms of current literature on technique, the colposcopic impression, cervical biopsy, and methods proposed to enhance appreciation of the highest-risk lesions. By outlining certain flaws in technique and discussing the proposal of new tests to supplement the current standard of care, this review aimed to highlight the need for future research to maintain sensitivity but improve the specificity of colposcopy.