Biomarker (ProEx C, p16(INK4A), and MiB-1) distinction of high-grade squamous intraepithelial lesion from its mimics

Role of Dual-Staining p16/Ki-67 in the Management of Patients under 30 Years with ASC-US/L-SIL

Patients diagnosed with low-grade squamous intraepithelial lesion ((L-SIL) or atypical squamous cells of undetermined significance (ASC-US) are subjected to additional investigations, such as colposcopy and biopsy, to rule out cervical intraepithelial neoplasia 2+ (CIN 2+). Especially in young patients, lesions tend to regress spontaneously, and many human papilloma virus (HPV) infections are transient. Dual-staining p16/Ki-67 has been proposed for the triage of patients with ASC-US or L-SIL, but no prospective study addressing only this subgroup of patients has been conducted so far. We performed a prospective study including all eligible patients referred for a loop electrosurgical excision procedure (LEEP) in the Department of Obstetrics and Gynecology of Timișoara University City Hospital. HPV genotyping and dual-staining for p16/Ki-67 were performed prior to LEEP, at 6 and 12 months after LEEP. A total of 60 patients were included in the study and completed the follow-up evaluation. We analyzed the sensitivity and specificity for biopsy-confirmed CIN2+ using the 95% confidence interval (CI) of high-risk human papilloma virus (HR-HPV), dual-staining p16/Ki-67, colposcopy, and combinations of the tests on all patients and separately for the ASC-US and L-SIL groups. Dual-staining p16/Ki-67 alone or in combination with HR-HPV and/or colposcopy showed a higher specificity that HR-HPV and/or colposcopy for the diagnosis of biopsy confirmed CIN2+ in patients under 30 years. Colposcopy + p16/Ki-67 and HR-HPV + colposcopy + p16/Ki-67 showed the highest specificity in our study.

A Comprehensive Review of Biomarker Use in the Gynecologic Tract Including Differential Diagnoses and Diagnostic Pitfalls

Morphologic (ie, hematoxylin and eosin) evaluation of the Mullerian tract remains the gold standard for diagnostic evaluation; nevertheless, ancillary/biomarker studies are increasingly utilized in daily practice to assist in the subclassification of gynecologic lesions and tumors. The most frequently utilized "biomarker" technique is immunohistochemistry; however, in situ hybridization (chromogenic and fluorescence), chromosomal evaluation, and molecular analysis can also be utilized to aid in diagnosis. This review focuses on the use of immunohistochemistry in the Mullerian tract, and discusses common antibody panels, sensitivity and specificity of specific antibodies, and points out potential diagnostic pitfalls when using such antibodies.

Predictive value of p16INK4a, Ki-67 and ProExC immuno-qualitative features in LSIL progression into HSIL

The current nested case-control study was conducted to explore the prognostic value of cyclin-dependent kinase inhibitor 2A (p16^INK4a), marker of proliferation Ki-67 (Ki-67) and immunohistochemical cocktail containing antibodies directed against topoisomerase IIα (TOP2A) and minichromosome maintenance 2 (MCM2) proteins (ProExC) immuno-qualitative features to predict low-grade squamous intraepithelial lesion (LSIL) progression. A total of 92 LSIL patients were followed-up for 2 years, where those with high-grade squamous intraepithelial lesion (HSIL) or persistent LSIL were designated as the case group and those who spontaneously regressed were designated as the control group. The infection status of human papillomavirus (HPV) was evaluated using flow-through hybridization and gene chip, whilst the expression of p16^INK4a, Ki-67 and ProExC were tested in LSIL patient biopsies by immunohistochemistry. All data were collected at the beginning of the follow-up and patient outcomes were diagnosed by histopathological examination. To analyze the risk factors for LSIL progression, sensitivity, specificity, positive-negative predictive value (PPV-NPV), positive-negative likelihood ratio (PLR-NLR), Youden's index (YI) and multinomial logistic regression analysis was performed. The expression rates of p16^INK4a, Ki-67, and ProExC were found to be higher in the progression group compared with those in the persistence and regression groups. Only p16^INK4a expression significantly associated with high-risk HPV infection. With respect to predicting HSIL, p16^INK4a staining was the most sensitive but Ki-67 staining was found to be the most specific. YI was the highest (42.1%) for p16^INK4a expression in the present study, followed by ProExC (39.5%) and Ki-67 (28.3%). However, the expression of ProExC was found to be an independent risk factor for LSIL progression into HSIL. In conclusion, whilst immunohistochemical staining for p16^INK4a, Ki-67, and ProExC can be used to predict HSIL progression, only ProExC expression can be applied an independent risk factor for LSIL progression.

Emerging biomarkers and clinical significance of HPV genotyping in prevention and management of cervical cancer

Cervical cancer is a growing and serious problem world-wide in women, but more acute in developing countries especially in Indian subcontinent. The main causative agent for the disease is Human Papilloma Virus (HPV). The history of the cervical cancer goes back to eighteenth century as the HPV infection is reported since 1800s. Presently, the genetic structure of HPV is well defined. Several screening tests including cytology and visual based screening and high risk HPV testing are available. Also available are various clinical and commercial diagnostic tests. However due to the lack of awareness and population-based screening programs, the morbidity and mortality rate is alarmingly high. There are new emerging biomarkers including E6/E7 mRNA, p16^ink4a, markers of aberrant S-phase induction, chromosomal abnormalities and miRNAs along with advanced genotyping methods. These markers have clinical significance and are helpful in disease prevention and management. Further, recent advancement in the field of metagenomics has increased the prospects of identifying newer microbes, viruses hitherto reported thus far in the context of HPV infection. Analysis of HPV cases using modern tools including genotyping using more powerful biomarkers is envisaged to enhance the prospects of early diagnosis, better prognosis, more reliable treatment and eventual management of the disease.

Surrogate markers for high-risk human papillomavirus infection in oral epithelial dysplasia: A comparison of p16, Ki-67, and ProExC

OBJECTIVE

The aim of this study was to determine the utility of surrogate markers of human papillomavirus (HPV) infection in the diagnosis of HPV-associated oral epithelial dysplasia (OED).

STUDY DESIGN

Twelve cases of oral dysplasia with histologic features of HPV infection were stained with surrogate markers for HPV (p16, Ki-67, and ProExC) on immunohistochemistry. A second group of 12 cases of oral dysplasia without histologic features of HPV infection was used for comparison. Reverse transcriptase polymerase chain reaction (RT-PCR) was used to confirm the presence of high-risk HPV (HR HPV) in p16-positive cases.

RESULTS

All of the surrogate markers showed a statistically significant association with HPV-positive OED (P < .001). The agreement between p16 and HPV positivity was the strongest (κ = 1.00), whereas Ki-67 showed very good association with HPV (κ = 0.83), and ProExC showed good association (κ = 0.75). In each case, the agreement was statistically significant (P < .001). Overall, each of the 3 markers showed good sensitivity; however, ProExC showed the lowest specificity.

CONCLUSIONS

The clinicopathologic features of 12 cases of HPV OED are reported. Diffuse p16 positivity is an accurate and reliable method for predicting HR HPV infection in both high and low grade cases of epithelial dysplasia with histopathologic features of HPV OED. The use of Ki-67 and ProExC did not demonstrate any additional diagnostic benefit in the diagnosis HPV OED.

p16 Staining of Cervical Biopsies May Decrease the Frequency of Unnecessary Loop Electrosurgical Excision Procedures

OBJECTIVE

Loop electrosurgical excision procedures (LEEPs) are negative for high-grade cervical intraepithelial neoplasia (CIN 2+) after a hematoxylin and eosin-based CIN 2+ colposcopic biopsy diagnosis in 14% to 24% of cases. This may be due to diagnostic errors or biopsy-related regression of the dysplasia. Because p16 immunohistochemical staining of cervical biopsies improves diagnostic accuracy, we hypothesized that p16-based cervical biopsy diagnoses may reduce the frequency of negative LEEPs.

MATERIALS AND METHODS

We performed a retrospective cross-sectional study of all cervical LEEPs completed at our institution from 2002 to 2012. We recorded patient age, sexual history, smoking history, pathologic diagnoses (including whether the diagnosis was p16 based), the number of days from biopsy to follow-up LEEP, and clinical follow-up. This yielded 593 study subjects meeting inclusion criteria of CIN 2+ colposcopic diagnoses with follow-up LEEP and 2 years of clinical follow-up. Colposcopic biopsies and follow-up LEEPs were reviewed and p16 immunostaining was performed on all samples to provide criterion standard results. Data were analyzed by χ and regression modeling.

RESULTS

Our practice employed p16 to aid cervical biopsy diagnoses by 2006. The frequency of negative LEEPs before 2006 was 12 (10%) of 126. The frequency dropped during the p16 era (2006-2012) to 23 (5%) of 467. Overall, we observed an inverse relationship between the frequency of p16 employment and the frequency of negative LEEP outcomes (R = 0.71; p < .001), independent of potential covariates.

CONCLUSIONS

Our data suggest that more accurate p16-based diagnoses may reduce the frequency of unnecessary LEEPs.

Characterization of topoisomerase II α and minichromosome maintenance protein 2 expression in anal carcinoma

The present study aimed to ascertain the significance of topoisomerase II α (TOP2A) and minichromosome maintenance protein (MCM) 2 expression in anal carcinoma. A total of 75 anal lesions were retrieved from the files of the Department of Pathology of Barretos Cancer Hospital (Barretos, Brazil) in order to verify the human papillomavirus (HPV) statuses of these lesions and characterize the immunohistochemical expression levels of TOP2A and MCM2 in anal carcinoma, as these are important markers for cervical HPV-induced lesions; their expression was also compared with respect to p16 and Ki-67. The vast majority of the cases tested positive for HPV16 (84%); 1 case tested positive for both HPV16 and HPV18. Positive HPV16 status was more frequent in early stages than in advanced stages (P=0.008). Positive immunohistochemical reactivity for MCM2 and TOP2A protein was observed in 71.6 and 100% of cases, respectively. Positive reactivity for p16 was significantly associated (P=0.001) with histological grade, and was more commonly expressed in squamous cell carcinoma than adenocarcinomas. HPV16 was strongly associated with positive p16 protein expression (76.6%). However, the high expression of Ki-67 combined with the high expression of p16 was predominantly observed in Stage III-IV cases. MCM2, TOP2A, p16 and Ki-67 exhibited intense positive staining in the anal lesions, indicating that these markers were significantly and constantly expressed in anal carcinoma.

ProEx C as Diagnostic Marker for Detection of Urothelial Carcinoma in Urinary Samples: A Review

The gold standard for the detection of urothelial carcinoma is represented by urethro-cystoscopy and biopsy. Both procedures are invasive and expensive and therefore cytology is often used as first approach to investigate on a possible neoplasia, being a safe and cost-effective diagnostic modality of evaluation. Because cytology alone is not highly sensitive for detection of low grade urothelial carcinoma and recurrence of the disease, several adjunct markers and urine based tests for urothelial carcinoma have been developed, which can help in the final diagnosis. In particular, ProEx C is an immunohistochemical cocktail containing antibodies direct against topoisomerase IIα (TOP2A) and minichromosome maintenance 2 (MCM2) proteins. It proved to be a valid biomarker especially in detecting squamous intraepithelial lesions in cervical liquid-based samples and in discerning these lesions from their mimickers, as well as in ovarian, endometrial, vulvar, primary and metastatic melanomas, breast, pancreatic and renal cell carcinomas. This brief review covers the effective utility of ProEx C as adjunct tool in assessing the urothelial lesions in urine cytology, also providing prognostic and therapeutic information to help in clinical decisions.

Cervical intraepithelial neoplasia in pregnancy: Interference of pregnancy status with p16 and Ki-67 protein expression

To date, there are evidence-based guidelines available for cervical dysplasia diagnosed in pregnancy. Certain functional biomarkers have proven useful in the prediction of regressing and non-regressing cervical intraepithelial neoplasia (CIN) lesions in non-pregnant women. In the present study, Ki-67 and p16 immunostaining were evaluated in different grades of CIN lesions diagnosed in pregnant or non-pregnant women with the aim to identify any differences in order to better understand the behavior of CIN in pregnancy. The current retrospective case-control study included 17 pregnant patients that conceived naturally with first-time onset of CIN occurring at no later than 16 gestational weeks. The control group included 17 non-pregnant patients matched for age, parity and number of previous sexual partners. Exclusion criteria included previous cervical treatment, immunocompromised status, chronic hepatitis B and/or C and cigarette smoking. p16 and Ki-67 protein expression were respectively detected using the CINtec Histology kit and monoclonal antibodies against Ki-67. p16 and Ki-67 staining were analyzed using a classification system based on the distribution of positivity on a semi-quantitative three point-scale. p16 and Ki-67 immune reactivity correlated positively with the grade of epithelial dysplasia in the total cohort of pregnant and non-pregnant patients; expression increased linearly from CIN1 to CIN3. Furthermore, the association between p16 immunostaining and CIN grade was significant in non-pregnant patients but not in pregnant patients. In pregnant patients, positivity for Ki-67 was less intense than in non-pregnant patients. These results appear to suggest that pregnancy status interferes with the expression of cellular proteins involved in cell-cycle regulation and the carcinogenic process induced by high-risk human papilloma virus, exhibiting increased variability in their staining.

Efficacy of p16 and Ki-67 immunostaining in the detection of squamous intraepithelial lesions in a high-risk HPV group

p16 and Ki-67 immunohistochemistry can be used as an ancillary method for the diagnosis of squamous intraepithelial lesion (SIL) versus atrophic change and atypical squamous metaplasia. The aim of the present study was to evaluate the efficacy of these two immunohistochemical markers in the accurate interpretation of cervical biopsies and correlate this data with human papilloma virus (HPV) infection status. The study included 103 formalin-fixed cervical punch and cone biopsy samples, with corresponding HPV DNA test data. Histopathological staining with hematoxylin and eosin, and immunohistochemical staining for p16 and Ki-67 were reviewed by two pathologists. The positivity of p16 and Ki-67 increased significantly with the severity of the cervical lesion in patients with a high-risk-HPV (HR-HPV) infection status (P<0.001). However, there was discordance in the HPV-negative group. Furthermore, concomitant diffuse, strong and block positive staining of p16, and a high Ki-67 index were implicated in high-grade SIL in the HR-HPV group. Thus, the two markers were efficient in advancing the diagnostic accuracy of cervical biopsies in the HR-HPV group; however, application of immunohistochemical results should be carefully considered in the HPV-negative group.

Efficacy of p16 and Ki-67 immunostaining in the detection of squamous intraepithelial lesions in a high-risk HPV group

p16 and Ki-67 immunohistochemistry can be used as an ancillary method for the diagnosis of squamous intraepithelial lesion (SIL) versus atrophic change and atypical squamous metaplasia. The aim of the present study was to evaluate the efficacy of these two immunohistochemical markers in the accurate interpretation of cervical biopsies and correlate this data with human papilloma virus (HPV) infection status. The study included 103 formalin-fixed cervical punch and cone biopsy samples, with corresponding HPV DNA test data. Histopathological staining with hematoxylin and eosin, and immunohistochemical staining for p16 and Ki-67 were reviewed by two pathologists. The positivity of p16 and Ki-67 increased significantly with the severity of the cervical lesion in patients with a high-risk-HPV (HR-HPV) infection status (P<0.001). However, there was discordance in the HPV-negative group. Furthermore, concomitant diffuse, strong and block positive staining of p16, and a high Ki-67 index were implicated in high-grade SIL in the HR-HPV group. Thus, the two markers were efficient in advancing the diagnostic accuracy of cervical biopsies in the HR-HPV group; however, application of immunohistochemical results should be carefully considered in the HPV-negative group.

Advancing rapid point-of-care viral diagnostics to a clinical setting

ABSTRACT 

We discuss here critical factors in ensuring the success of a viral diagnostic at the point of care. Molecular and immunoassay approaches are reviewed with a focus on their ability to meet the infrastructure and workflow limitations in clinical settings in both the developed and developing world. In addition to being low cost, easy-to-use, accurate and adapted for the intended laboratory and healthcare environment, viral diagnostics must also provide information that appropriately directs clinical treatment decisions. We discuss the challenges and implications of linking diagnostics to clinical decision-making at the point of care using three examples: respiratory viruses in the developed world, differential fever diagnosis in the developing world and HPV detection in resource-limited settings.

The Utility of Immunohistochemistry in the Differential Diagnosis of Gynecologic Disorders

Context

Immunohistochemistry has assumed an increasing role in the identification and characterization of gynecologic disorders including lesions with deceptively bland morphology, uncommon and underdiagnosed neoplasms, and neoplasms with specific genetic alterations associated with overexpression or loss of expression of specific proteins. The diagnostic accuracy has been significantly improved owing to the discovery and increasing experience with the tumor-associated biomarkers, and the increasing demand for precise tumor classification to assess suitability for the expanding therapeutic modalities including clinical trials.

Objective

To differentiate lesions of the gynecologic tract through the use of effective immunohistochemical panels.

Data Sources

Literature review and authors' personal practice experience.

Conclusions

The application of diagnostic and prognostic immunohistochemical panels has enabled pathologists to better guide therapeutic decisions and to better predict the clinical outcome. It is now well established that the use of ancillary testing, including immunohistochemistry, has a significant power in the identification, differentiation, and classification of reactive, premalignant, and malignant gynecologic disorders. This article discusses the utilities and pitfalls of the commonly used immunohistochemical markers in the context of overlapping morphologic features encountered in the uterus, ovaries, and fallopian tubes.

HPV-type distribution and reproducibility of histological diagnosis in cervical neoplasia in Poland

This study was performed to assess attribution of high grade cervical intraepithelial neoplasia (HG-CIN) and invasive cervical cancer (ICC) to human papillomavirus (HPV) genotypes and secondarily to assess reproducibility of HG-CIN/ICC diagnosis obtained in Poland. Formaldehyde fixed, paraffin embedded blocks of HG-CIN/ICC from two distant institutions were sent to a central laboratory together with original histological diagnoses. Central/expert review of histopathological specimens was performed and agreement between local and central/expert diagnoses was calculated. HPV detection and genotyping in the samples was carried out with the use of SPF10-LiPA25 technology. Results were analyzed for 205 HG-CIN and 193 ICC cases with centrally confirmed diagnoses. Kappa coefficients and 95 % confidence intervals for HG-CIN and ICC diagnoses were: 0.13 (0.09;0.17) and 0.19 (0.11;0.26) respectively. Cohen’s kappa coefficients for lesions with representative number of samples ranged from 0.01 for cervical intraepithelial neoplasia grade 2 to 0.75 for adenocarcinoma. HPV DNA was detected in 96.1 and 91.2 % of the confirmed HG-CIN and ICC specimens respectively. HPV positive HG-CIN was most commonly attributed to HPV types: 16 (62.8), 33 (7.8), 31 (6.6), 52 (3.7), 45 (2.6) and 58 (2.6 %). HPV positive ICC was most commonly attributed to HPV types: 16 (72.1), 18 (10.8), 33 (5.7), 45 (3.4) and 31 (1.7 %). Reproducibility of histological diagnosis of HG-CIN/ICC obtained in Poland generally increases with the severity of lesion and is lowest for cervical intraepithelial neoplasia grade 2 and highest for adenocarcinoma. Over 80 % of ICC cases are vaccine-preventable in Poland.

Immunocytochemical analysis of the cervical Pap smear

Although immunostained cervical Pap smears are not yet FDA approved for clinical use, it is very likely that they will become widely employed in the near future to identify neoplastic squamous and iendocervical glandular cells when screening liquid-based cytological preparations (i.e., SurePath™ or ThinPrep™). The current problem with cytology complemented by high-risk human papillomavirus (HPV) testing is poor specificity. HPV testing provides superior sensitivity, but many women are infected with the virus, while very few have had persistent infections leading to carcinoma. Pathologists routinely use antibodies directed against the cyclin-dependent kinase inhibitor p16 (p16(INK4a)) or a combination of antibodies directed against topoisomerase-2-alpha and minichromosome maintenance protein-2 (as in ProEx™ C) to improve diagnostic precision and accuracy in cervical tissue biopsies. This chapter will describe the immunocytochemical methods used by our group to immunostain cervical Pap smears and provide significantly improved positive predictive value when screening for cervical cancer.

HPV-related squamous neoplasia of the lower anogenital tract: an update and review of recent guidelines

Squamous cell carcinomas of the lower anogenital tract that are related to human papillomavirus (HPV) infection represent a significant disease burden worldwide. The diagnosis and management of their noninvasive precursors has been the subject of extensive study and debate over several decades, accompanied by an evolving understanding of HPV biology. Recent new consensus recommendations for the pathologic diagnosis of these precursor lesions were published in 2012, the result of the Lower Anogenital Squamous Terminology project cosponsored by the College of American Pathologists and the American Society for Colposcopy and Cervical Pathology. Most salient among the new guidelines are the recommendation to switch to a 2-tiered nomenclature (high-grade squamous intraepithelial lesion and low-grade squamous intraepithelial lesion) rather than the traditional 3-tiered "intraepithelial neoplasia" terminology, and the recommendation to expand use of the immunohistochemical marker p16 to distinguish between low-grade squamous intraepithelial lesion and high-grade squamous intraepithelial lesion/intraepithelial neoplasia 2. The goals of the project were to align diagnostic terminology with our knowledge of HPV biology, increase reproducibility, consolidate diverse systems of nomenclature, and ultimately better determine a patient's true cancer risk. The clinical guidelines for screening and management of cervical intraepithelial neoplasia have also been recently updated, most notably with a lengthening of screening intervals. In this review, we focus on the new guidelines put forth for pathologic diagnosis of HPV-related anogenital neoplasia, with discussion of the evidence behind them and their potential implications. We also provide an update on relevant biomarkers, clinical recommendations, and the newest developments relating to cervical neoplasia.

Expression of ProEx C in primary and metastatic urothelial carcinoma

BACKGROUND

ProEx C is an antibody cocktail targeting the expression of topoisomerase IIα and minichromosome maintenance protein-2. Both these proteins are over-expressed in the cell nucleus during aberrant S-phase induction of neoplastic cells, which leads to cell proliferation. The aim of this study was to determine whether ProEx C expression can detect primary and metastatic urothelial carcinoma (UC).

METHODS

Thirty one fine needle aspiration cell blocks (CB) with metastatic UC were identified. Immunohistochemical staining for ProEx C and thrombomodulin was performed. Additionally, staining for Pro Ex C was also performed in tissue microarrays (TMA) of 46 cases of primary UC and carcinomas from colon (80), stomach (31), pancreas (33), liver (92), ovary (24), endometrium (25), breast (60), lung (27), kidney (32), and prostate (44), as well as melanoma (22). Nuclear staining of ProEx C and membrane staining of thrombomodulin in at least 10% tumor cells was considered a positive result.

RESULTS

Both ProEx C and thrombomodulin have similar sensitivity for metastatic UC (84% vs. 77%, p=0.75; whereas ProEx C yielded a higher sensitivity of 93% for primary UC than thrombomodulin (72%, p=0.01). In addition to UC, ProEx C is also expressed in most of the malignant neoplasms tested in our TMA study, and has the highest sensitivity in colon and stomach carcinomas (94%).

CONCLUSION

ProEx C has high sensitivity for UC. However, it is also expressed in carcinomas of colon, stomach, breast, and lung carcinomas and may not be a useful marker for workup of metastatic UC.

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.

Ancillary Diagnostics in Gynecologic Cytology

Cytology has been the mainstay of cervical dysplasia and cancer screening in the United States. The specificity of a woman harboring a high-grade lesion when identified as high-grade squamous intraepithelial lesion on Pap test is high; however, the test suffers from low sensitivity. Epidemiology studies have demonstrated that human papillomavirus (HPV) types 16 and 18 account for most cervical squamous cell carcinomas. Tests have been developed to identify high-risk HPV, some specifically to identify HPV 16 and 18. Simultaneous to the increase in HPV detection methods, interdisciplinary groups are making recommendations on the managerial use of the tests.

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 &lt; .001), a higher rate of CIN2+ diagnoses (19.9% versus 16.4%, P &lt; .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.

Utility of ProEx C in the histologic evaluation of the neoplastic and nonneoplastic urothelial lesions

ProEx C is an antibody cocktail targeting the expression of topoisomerase IIα and minichromosome maintenance protein 2. ProEx C staining is being used mainly to assist in diagnoses of dysplasia in gynecological specimens. This study was designed to determine the utility of ProEx C in assessing the urothelial lesions. Sixty-four patient specimens were divided into 5 groups: group I, 22 benign; group II, 13 low-grade noninvasive papillary urothelial carcinoma; group III, 10 high-grade urothelial carcinoma in situ (flat lesion); and group IV, 19 high-grade noninvasive papillary and invasive urothelial carcinomas. ProEx C reactions were scored in basal, parabasal, intermediate, and superficial cell layers. A sample was recorded as positive when nuclear staining was seen in the cells of the intermediate and/or superficial layers. Of 22 cases in group I, 21 were negative for ProEx C with a specificity of 95%. Of 13 cases in group II, 11 had positive results with sensitivity of 85%. All cases in groups III and IV had positive staining pattern with ProEx C with a sensitivity of 100%. In this study, ProEx C stain had an overall 95% sensitivity and specificity with positive and negative predictive values of 98% and 91%, respectively, for detection of urothelial carcinoma. We conclude that ProEx C is effective in differentiating carcinoma in situ and benign urothelial lesions. It also resolves issues in low- versus high-grade papillary urothelial carcinomas. To our knowledge, this is the first publication on the diagnostic application of ProEx C in histopathology of the urothelial lesions.

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.

An evaluation of p16(INK4a) expression in cervical intraepithelial neoplasia specimens, including women with HIV-1

Although several studies have evaluated the role of p16(INK4a) as a diagnostic marker of cervical intraepithelial neoplasia (CIN) and its association with disease progression, studies regarding the role of p16(INK4a) in human immunodeficiency virus (HIV)-infected patients remain scarce. The present study was designed to determine the potential utility of p16(INK4a) as a diagnostic marker for CIN and invasive cervical cancer in HIV-positive and negative cervical specimens. An immunohistochemical analysis of p16(INK4a) was performed in 326 cervical tissue microarray specimens. Performance indicators were calculated and compared using receiving operating characteristics curve (ROC)/area under the curve. In HIV-1-negative women, the percentage of cells that was positive for p16(INK4a) expression was significantly correlated with the severity of CIN (p < 0.0001). A ROC curve with a cut-off value of 55.28% resulted in a sensitivity of 89%, a specificity of 81%, a positive predictive value of 91% and a negative predictive value of 78%. HIV-seropositive women exhibited decreased expression of p16(INK4a) in CIN2-3 specimens compared with HIV-negative specimens (p = 0.031). The ROC data underscore the potential utility of p16(INK4a) under defined conditions as a diagnostic marker for CIN 2-3 staging and invasive cervical cancer. HIV-1 infection, however, is associated with relatively reduced p16(INK4a) expression in CIN 2-3.

ProEx C as an adjunct marker to improve cytological detection of urothelial carcinoma in urinary specimens

BACKGROUND

ProEx C is an antibody cocktail targeting the expression of topoisomerase IIα and minichromosome maintenance protein-2. ProEx C staining is being used to assist in diagnoses of the gynecological specimens. This study was designed to determine the utility of ProEx C in urine cytology samples for improving the detection of urothelial carcinomas where a significant number of urine cytology specimens are diagnosed as "atypia."

METHODS

Sixty urinary specimens (12 negative, 13 positive, and 35 atypical cases) were stained with ProEx C, and ProEx C results were recorded as positive when nuclear staining was only seen in at least one morphologically atypical urothelial cell.

RESULTS

All 12 benign cytology samples showed negative staining with ProEx C. Twelve of 13 cases that had a malignant cytologic diagnosis showed a positive nuclear staining of the malignant cells. Eighteen of 35 cases with atypical cytologic diagnoses showed positive nuclear staining. Of the 35 cases with "atypia," 17 had a malignant histopathologic follow-up. In this study, ProEx C stain had an overall sensitivity of 78.4%, specificity of 95.7%%, positive predictive value of 96.7%, and negative predictive value of 73.3% for the detection of urothelial carcinoma.

CONCLUSIONS

ProEx C stain is a useful adjunct test to urine cytologic analysis, even in specimens with limited cellularity. In urinary smears, this test is most useful in stratification of the "atypical" diagnoses into benign and malignant subsets. To the authors' knowledge, this is the first study of ProEx C application in urine cytology as an adjunct marker for detection of urothelial carcinoma.

Evaluation of ProExC as a prognostic marker in oropharyngeal squamous cell carcinomas

ProExC expression has been shown to perform similarly to p16 as an aid in the diagnosis of cervical dysplasia but has not been well characterized in head and neck squamous cell carcinomas (SCC). The purpose of this study is to determine whether ProExC performs similarly to p16 as a prognostic marker in oropharyngeal SCC and to evaluate the threshold of ProExC and p16 staining that correlates with survival. ProExC, p16, and human papillomavirus DNA in situ hybridization were performed on tissue microarray (TMA) cores and whole sections from 62 patients with oropharyngeal SCC. Sensitivity and specificity for high-risk HPV and correlation with overall survival (OS), cancer-specific survival (CSS), and time to distant metastasis (TDM) were calculated for ProExC and p16 at different thresholds. ProExC did not prove to be a robust marker. It showed strong correlation with OS at a 66% threshold on TMA cores, but correlation with OS was lost on whole sections. It also exhibited low sensitivity (53.7%) on TMA cores and low specificity on whole sections (65%). ProExC at a 33% threshold exhibited unacceptably low specificity and did not correlate with OS, CSS, or TDM. Sensitivity and specificity of p16 varied predictably with threshold: higher sensitivity and lower specificity with lower thresholds and vice versa for higher thresholds. p16 at a 50% threshold offers a balance between sensitivity and specificity, and correlates with OS, CSS, and TDM on whole sections; correlation with TDM is lost on TMA cores. These findings indicate that ProExC does not perform well enough to be used as a prognostic marker in oropharyngeal SCC. p16 should be used and scored as positive when at least half the tumor is strongly stained.

The role of cytopathology in diagnosing HPV induced oropharyngeal lesions

HPV detection in fine needle aspirates from suspected head and neck metastasis may be useful in clinching the diagnosis of HPV related oral squamous cell carcinoma. Ascertaining the HPV status of a particular tumor on cytological specimens could be useful for prognostication as HPV-related tumors appear to have a better prognosis and clinical outcome. The various techniques of detection are reviewed.

Role of protein biomarkers in the detection of high-grade disease in cervical cancer screening programs

Since the Pap test was introduced in the 1940s, there has been an approximately 70% reduction in the incidence of squamous cell cervical cancers in many developed countries by the application of organized and opportunistic screening programs. The efficacy of the Pap test, however, is hampered by high interobserver variability and high false-negative and false-positive rates. The use of biomarkers has demonstrated the ability to overcome these issues, leading to improved positive predictive value of cervical screening results. In addition, the introduction of HPV primary screening programs will necessitate the use of a follow-up test with high specificity to triage the high number of HPV-positive tests. This paper will focus on protein biomarkers currently available for use in cervical cancer screening, which appear to improve the detection of women at greatest risk for developing cervical cancer, including Ki-67, p16^INK4a, BD ProEx C, and Cytoactiv HPV L1.

Deceiving high-grade cervical dysplasias identified as human papillomavirus non-16 and non-18 types by Invader human papillomavirus assays

High-grade cervical intraepithelial lesions (HGCINs) are easily diagnosed by established histologic criteria. However, we encountered problematic cases that are difficult to diagnose because features intermediate between dysplasia and metaplasia are present. p16 and Ki-67 immunostains proved HGCIN in these difficult and unusual cases. Because these are unusual cases of cervical dysplasia, we decided to type the human papillomavirus (HPV) using the Invader HPV test with analyte-specific reagents developed by Third Wave Technologies (Madison, WI, USA) (a new HPV screening assay applicable to tissue and amenable to rapid, sensitive, and specific detection of 14 high- to intermediate-risk HPV types) and a panel of immunostains. Results of these difficult cases are compared with classic HGCIN cases. We searched our pathology files over a period of 16 months for high-grade squamous intraepithelial lesion, cervical intraepithelial neoplasia II, cervical intraepithelial neoplasia III, and p16. To identify cases of difficult HGCIN with features intermediate between dysplasia and metaplasia, we reviewed all surgical cases of HGCIN that required p16 and Ki-67 diagnosis confirmation. Cases of interest were also stained with ProExC. Human papillomavirus screening and HPV 16/18 typing were performed by the Invader assays as described previously. Ten cases of classic HGCIN were easily diagnosed by hypercellularity, significant atypia, mitotic figures, and diffuse staining by p16, Ki67 and ProExC. The Invader assay identified HPV 16 (A9 positive/HPV16 positive) in 7 of 10 cases; the 3 others were A7 positive/not HPV18 (1) and A9 positive/not HPV16 (2). Eight cases of difficult HGCIN were identified. These showed only mild-to-moderate cellularity, a lack of significant atypia, absent-to-rare mitotic figures, and diffuse staining by p16, Ki-67, and ProExC. Human papillomavirus DNA was detected in 5 of 8 cases: only 1 was A9 positive/HPV16 positive, 1 was A5/A6 positive, 1 was A7 positive/not HPV18, and 2 were A9 positive/not HPV16. Three remaining cases demonstrated sufficient DNA to be analyzed by the Invader assay, but results were negative. This is a poorly recognized unusual group of cervical HGCIN with features intermediate between dysplasia and metaplasia that is easily confused by histologic examination. Immunostains prove the high-grade nature of these lesions, and Invader assay demonstrates association with HPV types other than 16/18 (ie, other HPV types detected by Invader assay). In this study, we present an unusual group of cases of high-grade dysplasia, not recognized by hematoxylin and eosin but identified by Ki67 and P16. It is very important to emphasize that this unusual group of high-grade dysplasias is associated with high-risk HPV but with types other than 16/18.

Human papillomavirus and cervical cancer: biomarkers for improved prevention efforts

While organized screening programs in industrialized countries have significantly reduced cervical cancer incidence, cytology-based screening has several limitations. Equivocal or mildly abnormal Pap tests require costly retesting or diagnostic work-up by colposcopy and biopsy. In low-resource countries, it has been difficult to establish and sustain cytology-based programs. Advances in understanding human papillomavirus biology and the natural history of human papillomavirus-related precancers and cancers have led to the discovery of a range of novel biomarkers in the past decade. In this article, we will discuss the potential role of new biomarkers for primary screening, triage and diagnosis in high-resource countries and their promise for prevention efforts in resource constrained settings.

The Role of Proteomics in the Diagnosis and Treatment of Women's Cancers: Current Trends in Technology and Future Opportunities

Technological and scientific innovations over the last decade have greatly contributed to improved diagnostics, predictive models, and prognosis among cancers affecting women. In fact, an explosion of information in these areas has almost assured future generations that outcomes in cancer will continue to improve. Herein we discuss the current status of breast, cervical, and ovarian cancers as it relates to screening, disease diagnosis, and treatment options. Among the differences in these cancers, it is striking that breast cancer has multiple predictive tests based upon tumor biomarkers and sophisticated, individualized options for prescription therapeutics while ovarian cancer lacks these tools. In addition, cervical cancer leads the way in innovative, cancer-preventative vaccines and multiple screening options to prevent disease progression. For each of these malignancies, emerging proteomic technologies based upon mass spectrometry, stable isotope labeling with amino acids, high-throughput ELISA, tissue or protein microarray techniques, and click chemistry in the pursuit of activity-based profiling can pioneer the next generation of discovery. We will discuss six of the latest techniques to understand proteomics in cancer and highlight research utilizing these techniques with the goal of improvement in the management of women's cancers.

Evaluation of cervical cone biopsies for coexpression of p16INK4a and Ki-67 in epithelial cells

Diffuse overexpression of p16(INK4a) in basal and parabasal cells of cervical epithelium is a hallmark of human papillomavirus-mediated transformation. Focal p16(INK4a) expression is occasionally observed in nondysplastic epithelium. In normal cells, expression of p16(INK4a) triggers cell cycle arrest. However, cells undergoing transformation in intraepithelial lesions actively proliferate. To prove that the different expression patterns of p16(INK4a) , i.e., focal versus diffuse, reflect biologically different entities, we hypothesized that p16(INK4a) -positive cells in epithelia displaying focal p16(INK4a) expression pattern do not coexpress proliferation-associated Ki-67 protein, while p16(INK4a) -positive cells in lesions with diffuse p16(INK4a) expression may do. A total of 138 cervical cone biopsies were stained for the expression of p16(INK4a) and Ki-67 using a primary antibody cocktail. All metaplastic lesions (n = 21) displayed focal staining for p16(INK4a) , and in all of these lesions p16(INK4a) -positive cells were found to be negative for Ki-67 expression. Diffuse expression of p16(INK4a) was observed in 12/21 (57.1%) cervical intraepithelial neoplasia (CIN) 1 lesions, all of them simultaneously showed Ki-67 immunoreactivity in a large proportion of p16(INK4a) -positive cells. Seventeen of 23 (73.9%) CIN2 lesions and all 27 (100%) CIN3/carcinoma in situ (CIS) as well as all 46 (100%) carcinoma cases displayed diffuse and combined expression of p16(INK4a) and Ki-67. Coexpression of Ki-67 and p16(INK4a) in the same cell is entirely restricted to cervical lesions displaying diffuse p16(INK4a) expression, whereas in lesions with focal p16(INK4a) expression, p16(INK4a) -expressing cells are negative for Ki-67. Thus, diffuse expression of p16(INK4a) reflects lesions with proliferation-competent cells, while p16(INK4a) -expressing cells associated with focal expression patterns are cell cycle arrested.

Ki-67 and ProExC are useful immunohistochemical markers in esophageal squamous intraepithelial neoplasia

Esophageal squamous intraepithelial neoplasia has been widely recognized as a precursor lesion for esophageal squamous cell carcinoma. Early detection offers the best prognosis for esophageal squamous cell carcinoma. The differentiation of squamous dysplasia from reactive change and the classification of squamous dysplasia into high-grade or low-grade are sometimes subjective and challenging. In this study, we sought to evaluate multiple biomarkers and to develop clinically useful adjunct tools for difficult esophageal squamous intraepithelial neoplasia cases. Immunohistochemical stains using antibodies against Ki-67, ProExC, p16, and p53 were performed on esophageal biopsy or resection specimens from 25 patients including 35 foci of high-grade dysplasia and 25 foci of low-grade dysplasia, and from 10 control cases containing 52 foci of normal/reactive hyperplasia. In situ hybridization tests for human papillomavirus were performed in 11 cases. The immunostains for all 4 markers were scored as negative, intermediate, and strong according to established criteria. Intermediate and strong Ki-67 and ProExC staining showed similar detecting power and exhibited very high sensitivity and specificity for distinguishing normal/reactive hyperplasia from esophageal squamous intraepithelial neoplasia and normal/reactive hyperplasia from low-grade esophageal squamous intraepithelial neoplasia. Strong Ki-67 staining was exclusively seen in high-grade esophageal squamous intraepithelial neoplasia, which provided additional value in distinguishing high-grade from low-grade esophageal squamous intraepithelial neoplasia. Strong ProExC staining was also seen in most high-grade esophageal squamous intraepithelial neoplasia foci (80%). Although the frequencies of intermediate/strong staining patterns of p53 increased with increasing degree of dysplasia, the sensitivity of p53 was much lower than that of Ki-67 and ProExC. p16 did not show consistent immunostain pattern in the normal/reactive hyperplasia and esophageal squamous intraepithelial neoplasia. Two (18%) of 11 tested cases were positive for human papillomavirus infection. This study demonstrates that both Ki-67 and ProExC can be used as an adjunct tool for diagnosing difficult cases of esophageal squamous intraepithelial neoplasia.

Neoplastic Lesions of the Cervix

This review presents a discussion of the gross and microscopic features, diagnosis, differential diagnosis, and prognosis of neoplastic lesions of the cervix. Biomarkers are discussed for each entity presented - cervical intraepithelial neoplasia, squamous carcinoma, glandular neoplasms, adenocarcinoma in situ, adenosquamous carcinoma, and others.

Assessing for primary oropharyngeal or nasopharyngeal squamous cell carcinoma from fine needle aspiration of cervical lymph node metastases

In fine needle aspirates of cervical lymph nodes with metastatic squamous cell carcinoma (SCC), the site of origin may not be clinically evident. The distinction between oropharyngeal and nasopharyngeal primary SCC has important management consequences. In the current study, we evaluated metastatic SCC for HPV types 16, 18, 31, 33, 51 (by in situ hybridization[ISH]), p16 and ProExC (surrogate HPV markers), and Epstein Barr Virus reported in nasopharyngeal SCC. Forty patients diagnosed between 2004 and 2008, with adequate cell block material were identified. ISH for high risk HPV and EBV (EBER), and immunohistochemistry for p16 and ProExC were performed. Primary site was designated in 31 cases with 26 head and neck including 11 oropharyngeal and 2 nasopharyngeal, and 5 other sites. High risk HPV was detected in 9 cases (22.5%), p16 in 16 (40%), ProExC in 35 (87.5%), and EBER in 2 (5%). All cases with high risk HPV ISH also showed overexpression of p16. The sensitivity for HPV infection by both surrogate markers was 100%; specificity for p16 and ProExC was 78.7 and 16.1%, respectively. Seven (63.6%) oropharyngeal SCC were positive for HPV ISH and negative for EBV; one nasopharyngeal SCC (50%) was EBER positive and HPV negative. HPV and EBER detection can serve as indicators for oropharyngeal and nasopharyngeal primary SCC, respectively, however our data show that only a subset (63.6%) of oropharyngeal SCC are high risk HPV-related. Additionally, despite their high sensitivity for HPV infection, surrogate markers, especially ProExC, lack specificity.

Efficacy of p16 and ProExC immunostaining in the detection of high-grade cervical intraepithelial neoplasia and cervical carcinoma

We compared the efficacy of p16 and ProExC immunostaining in detecting cervical intraepithelial neoplasia (CIN) 2+ in 136 formalin-fixed, paraffin-embedded cervical tissue specimens with consensus diagnoses of normal cervix, CIN 1, CIN 2, CIN 3, and carcinoma. Diffuse staining patterns of more than half the thickness of CINs and more than 10% of carcinoma cells were scored as positive. The positivity of p16 and ProExC increased significantly with the severity of cervical lesion (P < .001). For CIN 2+ or CIN 3+, p16 immunostaining was more sensitive (79% for CIN 2+; 90% for CIN 3+) than ProExC immunostaining (67% for CIN 2+; 84% for CIN 3+). ProExC showed higher specificity for CIN 3+ compared with p16. Specimens with p16+/ProExC+ results showed the highest specificity (100% for CIN 2+; 93% for CIN 3+), suggesting that these 2 biomarkers can be used together to distinguish CIN 2/3 from its mimics in cervical biopsy specimens.

Comparison of p16INK4a and ProEx C immunostaining on cervical ThinPrep cytology and biopsy specimens

ProEx C and p16(INK4a) staining of cytology/histology specimens have recently been explored to help distinguish high-grade squamous intraepithelial lesions (HSIL) from benign mimics. The goal of this study was to evaluate the performance characteristics of p16 and ProEx C in tissue and patient matched ThinPrep liquid-based cytology specimens. Residual cervical ThinPrep cytology specimens and tissue blocks (N = 64) from 63 patients were stained with p16 and ProEx C. Review of immunostained material, Papanicolaou and H&E stained slides was performed by two cytopathologists. The cytology slides were evaluated for the presence or absence of squamous atypia as well as immunoreactivity. Histologic specimens were interpreted as negative, indeterminate, or positive for each immunostain. There was 86% agreement (55/64) between the p16 and ProEx C stains on tissue specimens. Eleven specimens were interpreted as positive for both stains. All had a low- or high-grade squamous lesion on the corresponding H&E section. ProEx C was able to identify four low-grade squamous intraepithelial lesion specimens that were interpreted as negative by p16. All four HSIL specimens demonstrated p16 and ProEx C staining. However, 84% of cytology negative specimens demonstrated false-positive staining. Clinical utilization of both stains, combined with morphologic features, may be beneficial for confirming HSIL on histologic specimens. ProEx C and/or p16 immunostains may lead to a false-positive result in cytology specimens due to staining of normal appearing cells.

MOLECULAR MARKERS OF EARLY CERVICAL NEOPLASIA

Pure morphological distinction of high-grade squamous intraepithelial lesions (HSILs) from their mimics can be challenging. Diagnosis can be difficult with nonconventional HSILs associated with a metaplastic phenotype, squamous intraepithelial lesions (SILs) that defy precise classification such as "eosinophilic dysplasias", and those that overlap with columnar neoplasms, including stratified variants of adenocarcinoma in situ ("SMILE"). Gene expression and protein profiling have identified biomarkers with the potential to decrease diagnostic variability and increase specificity of histological and cytological analysis. Among the ones clinically useful for HSIL detection are p16(INK4A) and MIB-1 which complement each other, differentiating SIL from normal/atrophic (MIB-1 low) or reactive/immature metaplastic (p16(INK4A) scattered) epithelium. Additional markers, including ProEx(TM) C, have been proposed but their added value is yet to be established. In the final analysis, biomarkers are most helpful for distinguishing benign immature or atrophic proliferations from HSIL. The distinction of LSIL from HSIL must be made on the hematoxylin and eosin-stained section and should be made with care, given the potential consequences of a diagnosis of CIN2 or CIN3.