Immunostaining of p16INK4a/Ki-67 and L1 Capsid Protein on Liquid-based Cytology Specimens Obtained from ASC-H and LSIL-H Cases

Background: Atypical squamous cell cannot exclude high-grade squamous intraepithelial lesion (ASC-H) and low-grade intraepithelial lesion cannot exclude high-grade squamous intraepithelial lesion (LSIL-H) are ambiguous diagnostic entities for the prediction of high-grade cervical lesion. Objective and reproducible tests for predicting high-grade cervical lesions are needed to reduce unnecessary colposcopic referrals or follow-ups.Objective: We aimed to identify an adequate set of adjunctive markers to predict cervical intraepithelial neoplasia grade 2+ (CIN2+) in residual liquid-based cytology specimens (LBCS).Methods: We conducted p16 ^INK4a/Ki-67 and L1 capsid protein immunostaining and human papillomavirus (HPV) DNA typing on 56 LBCS diagnosed with ASC-H or LSIL-H, all of which were subjected to histologic confirmation or follow-up cytologic examination.Results: Positivity for p16 ^INK4a/Ki-67 was associated with a histology of CIN2+ (P=0.047) and CIN3+ (P=0.002). Negativity for L1 capsid protein was associated with CIN2+ confirmed at follow-up (P=0.02).Positivity for high-risk HPV (HR-HPV) was associated with CIN2+ confirmed at follow-up (P=0.036) and a histology of CIN2+ (P=0.037). The sensitivity, specificity, positive predictive value, and negative predictive value for predicting follow-up CIN2+ were 76.2%, 51.4%, 48.5%, and 78.3%, respectively, for p16 ^INK4a/Ki-67 immunostaining; 95.2%, 34.3%, 46.5%, and 92.3%, respectively, for L1 capsid protein; and 66.7%, 67.7%, 54.5%, and 77.8%, respectively, for HR-HPV. The classification and regression tree analysis showed that the combined results of p16 ^INK4a/Ki-67 andL1 capsid protein immunostaining and the HR-HPV test, conducted sequentially, correctly classified 81.8% of samples (27/33)in the prediction of a histology of CIN2 + in ASC-H or LSIL-H. For determination of the histology of cervical intraepithelial neoplasia grade 3+ (CIN3+)in ASC-H or LSIL-H, we found that the combined results of p16 ^INK4a/Ki-67 and L1 capsid protein immunostaining correctly classified 78.8% (26/33) of samples.Conclusions: p16^INK4a/Ki-67 and L1 capsid protein immunostaining and HR-HPV testing of residual LBCS diagnosed with ASC-H or LSIL-H are useful objective biomarkers for predicting CIN2+. Immunostaining for p16^INK4a/Ki-67 and L1 capsid protein are sufficient to predict CIN3+.     

Comparative study of the expression of cellular cycle proteins in cervical intraepithelial lesions

Interaction of human papilloma virus oncoproteins E6 and E7 with cell cycle proteins leads to disturbances of the cell cycle mechanism and subsequent alteration in the expression of some proteins, such as p16^INK4a, cyclin D1, p53 and KI67. In this study, we compared alterations in the expression of these proteins during several stages of intra-epitelial cervical carcinogenesis. Accordingly, an immunohistochemical study was performed on 50 cervical biopsies, including negative cases and intraepithelial neoplasias. The expression patterns of these markers were correlated with the histopathological diagnosis and infection with HPV. The p16^INK4a, followed by Ki67, showed better correlation with cancer progression than p53 and cyclin D1, which recommends their use in the evaluation of cervical carcinogenesis. These monoclonal antibodies can be applied to cervical biopsy specimens to identify lesions transformed by oncogenic HPV, separating CIN 1 (p16^INK4a positive) and identifying high-grade lesions by an increase in the cellular proliferation index (Ki67). In this way, we propose immunomarkers that can be applied in clinical practice to separate patients who need a conservative therapeutic approach from those who require a more aggressive treatment.     

P16<Superscript>INK4a</Superscript> expression and progression risk of low-grade intraepithelial neoplasia of the cervix uteri

The aim of the study was to evaluate the immunohistochemical expression of p16^INK4a as a marker of progression risk in low-grade dysplastic lesions of the cervix uteri. p16^INK4a immunohistochemistry was performed on 32 CIN1 with proven spontaneous regression of the lesion in the follow-up (group A), 31 (group B) with progression to CIN3 and 33 (group C) that were randomly chosen irrespective of the natural history of the lesion. p16^INK4a staining pattern was scored as negative (less than 5% cells in the lower third of dysplastic epithelium stained), as focally positive (25%) and as diffuse positive (>25%). A diffuse staining pattern was detected in 43.8% of CIN1 of group A, 74.2% of group B and 56.3% of group C. No p16^INK4a staining was detected in 31.3% and 12.9% CIN1 lesions of groups A and B, respectively. Overall, 71.4% and 37.8% of p16^INK4a-negative and diffusely positive CIN1 had regressed at follow-up, whereas 28.6% and 62.2% negative and diffusely positive CIN1 were progressed to CIN3, respectively (P<0.05). All CIN3 lesions analyzed during follow-up of group B were diffusely stained for p16^INK4a. Although p16^INK4a may be expressed in low-grade squamous lesions that undergo spontaneous regression, in this study, CIN1 cases with diffuse p16^INK4a staining had a significantly higher tendency to progress to a high-grade lesion than p16^INK4a-negative cases. p16^INK4a may have the potential to support the interpretation of low-grade dysplastic lesions of the cervix uteri.     

p16INK4A expression in cervical premalignant and malignant lesions

p16^INK4a is a cyclin-dependent kinase (CDK) inhibitor which decelerates cell cycle by inactivating CDKs that phosphorylate pRb. Human Papillomavirus persistent infection plays an important role on cervical carcinogenesis, mainly by the action of two viral oncoproteins, E6 and E7, which interact with p53 and pRb, respectively. Increasing expression of E6 and E7 in dysplastic cervical cells might thus be reflected by increased expression of p16^INK4a. Recent studies revealed that p16^INK4a expression could be a marker for dysplastic and neoplastic cervical cells. The aim of this study was to analyze p16^INK4a expression in cervical preneoplastic and neoplastic lesions and correlate with lesion grade. Expression of p16^INK4a was analyzed by immunohistochemistry. A total of 6 low-grade squamous intraepithelial lesion (LSIL), 21 high-grade squamous intraepithelial lesions (HSIL) and 27 cancer samples were studied. In HPV-positive cervical samples (n = 48), p16^INK4a expression was observed in 1 of 3 LSIL, in 18 of 19 HSIL and in all 26 cancer cases. These results are in accordance with the hypothesis that functional inactivation of pRb by HPV-E7 protein induces p16^INK4a expression in cervical lesions. In our study, a statistically significant association was observed between cervical lesion grade and p16^INK4a expression (P < 0.001).     

Human papillomavirus genotyping and p16INK4a expression in cervical intraepithelial neoplasia of adolescents.

Adolescents have high rates of human papillomavirus (HPV) infection, and persistent high-risk HPV infection can lead to the development of cervical cancer. The cyclin-dependent kinase inhibitor, p16(INK4a) is overexpressed in cervical intraepithelial neoplasia (CIN), probably due to a persistent and integrated HPV infection. This study investigated p16(INK4a) expression, grades of CIN, and high-risk HPV infection in adolescent cervical biopsies. Biopsies were immunohistochemically stained for p16(INK4a). The presence of wide-spectrum, low-risk, or high-risk HPV was determined by amplifying DNA extracted from the cervical biopsies. Biopsies were classified as cervicitis, 15 cases; CIN 1, 48 cases; CIN 2, 46 cases, and CIN 3, 52 cases. The distribution of p16(INK4a) staining was graded as patchy, diffuse basal, and diffuse full thickness. Pearson's chi(2) tests analyzed the relationships between p16(INK4a) staining, HPV infection, and CIN. Biopsies of cervicitis were negative for HPV and for p16(INK4a) expression. High-risk HPV 16, 18, and 31 increased from 18% in CIN 1 to 66% in CIN 2/3 (P<0.001). In CIN 1, p16(INK4a) was positive in 44% of biopsies with 35% showing patchy, 7% diffuse basal, and one case (2%) showing diffuse full thickness staining. In CIN 2/3, p16(INK4a) was positive in 97% of biopsies with 23% showing patchy, 21% diffuse basal, and 53% diffuse full thickness staining. The difference in the proportions of biopsies showing patchy p16(INK4a) staining in CIN 1 and diffuse full thickness staining in CIN 2/3 was significant (P<0.001). In CIN 1, 61% of high-risk HPV-positive biopsies were p16(INK4a) negative, while all high-risk HPV-positive CIN 2/3 biopsies were p16(INK4a) positive. Diffuse, full thickness p16(INK4a) expression discriminated low-grade from high-grade CIN and appears to be a marker of persistent high-risk HPV infection.     

Significance of p53-binding protein 1 nuclear foci in uterine cervical lesions: endogenous DNA double strand breaks and genomic instability during carcinogenesis

Matsuda K, Miura S, Kurashige T, Suzuki K, Kondo H, Ihara M, Nakajima H, Masuzaki H & Nakashima M
(2011) Histopathology 59 , 441–451 Significance of p53‐binding protein 1 nuclear foci in uterine cervical lesions: endogenous DNA double strand breaks and genomic instability during carcinogenesis Aims: A defective DNA damage response can result in genomic instability (GIN) and lead to transformation to cancer. As p53‐binding protein 1 (53BP1) localizes at the sites of DNA double strand breaks (DSBs) and rapidly forms nuclear foci (NF), the presence of 53BP1 NF can be considered to be an indicator of endogenous DSBs reflecting GIN. Our aim was to analyse the presence of DSBs by immunofluorescence for 53BP1 expression in a series of cervical lesions, to evaluate the significance of GIN during carcinogenesis. Methods and results: A total of 80 archival cervical tissue samples, including 11 normal, 16 cervical intraepithelial neoplasia (CIN)1, 15 CIN2, 24 CIN3 and 14 squamous cell carcinoma samples, were analysed for 53BP1 NF, human papillomavirus (HPV) infection, and p16^INK4a overexpression. The number of 53BP1 NF in cervical cells appeared to increase with progression during carcinogenesis. The distribution of 53BP1 NF was similar to that of the punctate HPV signals as determined by in‐situ hybridization and also to p16^INK4a overexpression in CIN, suggesting an association with viral infection and replication stress. Conclusions: Immunofluorescence analysis of 53BP1 expression can be a useful tool with which to estimate the level of GIN. During cervical carcinogenesis, GIN may allow further accumulation of genomic alterations, causing progression to invasive cancer.     

Increased expression of oncogene-induced senescence markers during cervical squamous cell cancer development

Purpose: To investigate the expression of p15^INK4b, p16^INK4a and p21^Waf1/Cip1 in specimens from cases of normal cervical epithelium (NCE), cervical intraepithelial neoplasia (CIN) and squamous cell carcinoma (SCC), and to evaluate whether there is evidence implicating oncogene-induced senescence (OIS) in cervical squamous cell cancer development. Methods: The immunohistochemical expression of p15^INK4b, p16^INK4a and p21^Waf1/Cip1 were investigated in formalin-fixed paraffin-embedded specimens from 19 NCE, 51 CIN and 21 SCC cases, respectively. Comparisons among different groups for each marker were performed with Chi-square test. Results: The expression of p15^INK4b, p16^INK4a and p21^Waf1/Cip1 were significantly higher in both CIN and SCC compared to NCE. Furthermore, the expression of p15^INK4b and p21^Waf1/Cip1 was significantly higher in CIN П compared to CIN І, and these expressions were statistically higher in CIN Ш compared to CIN П, respectively. The p16^INK4a expression was significantly higher in CIN Ш compared to CIN І. Conclusions: The results suggested that the senescence programs mediated by p15^INK4b, p16^INK4a and p21^Waf1/Cip1 were activated during the stage of CIN and SCC, and demonstrated that senescence may play important role in preventing from NCE to SCC.     

Expression Pattern and Subcellular Localization of Human Papillomavirus Minor Capsid Protein L2

The expression pattern of human papillomavirus (HPV) capsid antigen L2 is poorly described, and the significance of its localization with both promyelocytic leukemia protein (PML) and Daxx in a subnuclear domain, nuclear domain 10 (ND-10), when ectopically expressed in tissue culture cells is controversial. To address whether ND-10 localization of L2 occurs in natural cervical lesions, we used a HPV16 and HPV18 L2-specific monoclonal antibody (RG-1), in addition to rabbit antiserum to HPV6 L2, to localize L2. Immunohistochemical staining with RG-1 produced diffuse staining in the nuclei of some cells located within the superficial epithelial layers in eight of nine cases of HPV16/18⁺ cervical intraepithelial neoplasia grade 1 (CIN1); however, no staining was observed in HPV16/18⁺ high-grade CIN (0 of 8 cases), normal cervical epithelium (0 of 20 cases), cervical squamous cell carcinoma (0 of 102 cases), adenocarcinoma (0 of 51 cases), or adenosquamous carcinoma (0 of 6 cases). HPV16/18⁺ cervical lesions that express L2 exhibit higher HPV16/18 genome copies per cell compared with those that do not positively stain with RG-1 (P = 0.04). RG-1 staining of HeLa cells transfected with L2 expression constructs was frequently concentrated in the ND-10, particularly in cells expressing high levels of L2, and co-localized with the cellular markers of ND-10, PML, and Daxx. In contrast, L2 was primarily diffuse within the nucleus and distinct from ND-10 as defined by PML immunofluorescent staining in CIN lesions, condylomata, and HPV16-transduced organotypic cultures.     

High‐risk human papillomavirus load and biomarkers in cervical intraepithelial neoplasia and cancer

The purpose of this study was to examine the implication of high‐risk human papillomavirus (HPV) load in cervical intraepithelial neoplasia (CIN) and cancer, and to detect biomarkers in cervical disease. We conducted high‐risk HPV DNA load and cervical cytology tests in 343 women, cervical tissue biopsy in 143 women, and immunohistochemistry for p16^INK4A, cyclin D1, p53, cyclooxygenase‐2, Ki‐67, GLUT1, hPygopus2, and beta‐catenin. As a result, HPV load [relative light units (RLU) value] was correlated with the histological severity of cervical disease (p < 0.05). In the ‘atypical squamous cells of undetermined significance’ cytology group, 2.385 of HPV load seemed to be the cut‐off value at which ‘benign’ or CIN I can be differentiated from ‘CIN II or more severe’ (AUC = 0.712), but not statistically significant. The relative risk (odds ratio) of p16^INK4A and GLUT1 overexpression increased gradually according to the histological severity of cervical disease. The p16^INK4A showed statistically significant odds ratios in CIN II, CIN III, and cancer; GLUT1, in CIN II and CIN III; hPygopus2, in CIN III; and beta‐catenin, in CIN III and cancer. Conclusively, HPV load, p16^INK4A, and GLUT1 can be instrumental in predicting the severity of HPV‐related cervical disease. The beta‐catenin/hPygopus2 signaling may be involved in proceeding to CIN III.     

Role for p16(INK4a) in progression of gastrointestinal stromal tumors of the stomach: alteration of p16(INK4a) network members

Gastrointestinal stromal tumors feature a wide spectrum of biologic behavior, ranging from benign to extremely malignant. To determine the role of p16^INK4a alteration in progression of gastrointestinal stromal tumors of the stomach, we have investigated protein expression and gene methylation in correlation with clinicopathologic factors and survival. In addition to immunohistochemical analysis of p16^INK4a in a series of 95 cases, real-time quantitative methylation specific polymerase chain reaction for p16^INK4a and immunostaining for cyclin D1, cyclin E, pRb, DP-1, E2F-1, and Ki-67 were also evaluated in randomly selected samples. The p16^INK4a labeling indices ranged from 0% to 74% (median, 21%), demonstrating a significant inverse correlation with size (P = .046). On univariate (P = .003) and multivariate (P = .067) analyses, loss of p16^INK4a expression increased the likelihood of a poor tumor-related survival. In addition, size (P = .036) and the mitotic index (P = .005) had independent prognostic influence. The p16^INK4a methylation index, which ranged from 0% to 100% (median, 17%), was significantly higher in larger tumors (P < .001) and in high-risk category lesions (P = .001) and inversely correlated with protein expression. Hierarchical cluster analysis based on expression of p16^INK4a network members identified 2 clusters in 27 randomly selected tumor samples, containing 11 and 16 tumors each. Former cluster samples demonstrated higher risk category (P = .022), higher p16^INK4a methylation (P < .001), and more reduced pRb expression (P < .018). In addition, p16^INK4a network members clustered into 2 groups: (1) showing down-regulated p16^INK4a protein and up-regulating of both cyclin D1 and DP-1 and (2) down-regulated pRb and up-regulated E2F-1. We conclude that p16^INK4a alteration has an important role in progression of gastrointestinal stromal tumors of the stomach. Furthermore, the study provides a possible link between regulation of p16^INK4a network members and gastrointestinal stromal tumors.     

Prognostic value of p16INK4a as a marker of clinical evolution in patients with cervical intraepithelial neoplasia grade 3 (CIN 3) treated by cervical conization

The aim of this study was to assess the prognostic value of p16^INK4a as a marker of post‐conization relapse in patients treated for cervical intraepithelial neoplasia grade 3 (CIN 3). A retrospective study of 76 women with CIN 3 diagnoses, treated at the Hospital of Santa Casa de Misericórdia of São Paulo (Brazil) between January 2003 and September 2004, was performed. The study samples were obtained from cervical conization procedures, where paraffin blocks containing areas with the greatest amount of neoplastic tissue were selected. Immunohistochemical techniques were used on individual paraffin blocks for each case to detect p16^INK4a protein expression. The p16^INK4a cell counts were performed in 10 different high‐amplification fields (400x) by light microscopy and total cell count expressed as number of cells per mm². Patients involved in this study were followed up at the colposcopy outpatient unit for at least 48 months after cervical conization. The correlation of p16^INK4a values with post‐conization evolution in the patients (disease relapse or disease free) was determined. A significantly higher count of cells expressing p16^INK4a was found in those patients with disease relapse during follow‐up (p < 0.001). The variables age, number of gestations, and births correlated positively with number of cells expressing p16^INK4a cells (p < 0.001; p = 0.001; 0.009, respectively). No correlation was found for the variables menopause, hormonal contraception, or smoking (p = 0.369, 0.425 and 0.853, respectively). p16^INK4a can be considered a biomarker of cervical intraepithelial neoplasia grade 3 cases presenting high risk of relapse or evolution to invasive carcinoma.     

p16INK4A overexpression and HPV infection in uterine cervix adenocarcinoma

Human papillomaviruses (HPVs) are causally involved in the genesis of cervical carcinomas and their precursors, and there is a strong relationship between the cyclin-dependant kinase inhibitor p16^INK4A and HPV infection. This study was carried out to assess the correlations between p16^INK4A expression as an early biomarker of the endocervical adenocarcinoma and HPV infection. p16^INK4A expression and HPV typing were performed on 46 samples including 5 normal endocervix, 9 benign lesions of the endocervix, 25 endocervical adenocarcinomas, and 7 endometrioid adenocarcinomas of the uterine corpus. A semiquantification of the p16^INK4A immunostaining was realized (using both the staining intensity and the percentage of positive cells) and was graded from 0 to 15. All of the 25 endocervical adenocarcinomas overexpressed p16^INK4A; the adjacent epithelium and the connective tissue were strictly negative. No p16^INK4A was detected in nine benign endocervical lesions and in five normal endocervix. Few endometrioid adenocarcinomas of the uterine corpus that infiltrate the endocervix exhibited a low immunoreactivity (score 0/15 or 1/15). This pattern of expression is significantly associated with HPV infection (p<10 ⁻³), mainly high-risk HPV types (p=0.02). Our results suggest that p16^INK4A is a putative molecular biomarker that consistently discriminates uterine cervix adenocarcinomas from benign lesions and from endometrioid adenocarcinomas of the uterine corpus .     

p16INK4A as a marker for cervical dyskaryosis: CIN and cGIN in cervical biopsies and ThinPrep smears

AIM: To examine the potential of p16(INK4A) as a biomarker for dysplastic squamous and glandular cells of the cervix in tissue sections and ThinPrep smears. METHODS: Immunocytochemical analysis of p16(INK4A) expression was performed on 22 normal cervical tissue samples, five cervical glandular intraepithelial neoplasia (cGIN), 38 cervical intraepithelial neoplasia 1 (CIN1), 33 CIN2, 46 CIN3, and 10 invasive cancer cases (eight squamous and two adenocarcinomas). All samples were formalin fixed and paraffin wax embedded, and immunohistochemical analysis was carried out using a mouse monoclonal anti-p16(INK4A) antibody after antigen unmasking. The staining intensity was assessed using a 0 to 3 scoring system. In addition, the expression status of p16(INK4A) was examined in 12 normal ThinPrep smears, one smear exhibiting cGIN, and a total of 20 smears exhibiting mild, moderate, and severe dyskaryosis. Human papillomavirus (HPV) detection was carried out using a modified SYBR green assay system. Fluorogenic polymerase chain reaction (PCR) and solution phase PCR were used for specific HPV typing. RESULTS: p16(INK4A) immunoreactivity was absent in all normal cervical tissues examined. Dysplastic squamous and glandular cells were positive for p16(INK4A) expression in all cases included in this study, except for one CIN3 case. p16(INK4A) expression was mainly nuclear in CIN1 cases, and both nuclear and cytoplasmic in CIN2, CIN3, cGIN, and invasive cases. All cases positive for HPV expressed the p16(INK4A) protein, although not all cases found positive for p16(INK4A) were HPV positive. In general, the p16(INK4A) staining intensity was lower in cases negative for HPV or those containing a low risk HPV type. CONCLUSION: This pattern of overexpression demonstrates the potential use of p16(INK4A) as a diagnostic marker for cervical squamous and also glandular neoplastic lesions. In addition, the technique can be used to identify individual dyskaryotic cells in ThinPrep smears. Thus, p16(INK4A) is a useful marker of cervical dyskaryosis.     

p16INK4A, CDC6, and MCM5: predictive biomarkers in cervical preinvasive neoplasia and cervical cancer

AIM: To analyse and compare expression patterns of three potential biomarkers-p16(INK4A), CDC6, and MCM5-and evaluate their use as predictive biomarkers in squamous and glandular cervical preinvasive neoplasia. METHODS: Immunocytochemical analysis of p16(INK4A), MCM5, and CDC6 expression was performed on 20 normal, 38 cervical intraepithelial neoplasia 1 (CIN1), 33 CIN2, 46 CIN3, 10 squamous cell carcinoma, 19 cervical glandular intraepithelial neoplasia (cGIN), and 10 adenocarcinoma samples. Staining intensity was assessed using a 0-3 scoring system. p16(INK4A), MCM5, and CDC6 expression was also examined in ThinPrep slides exhibiting mild, moderate, and severe dyskaryosis. Human papillomavirus (HPV) was detected using a modified SYBR green assay. Fluorogenic polymerase chain reaction (PCR) and solution phase PCR were used for specific HPV typing. RESULTS: All three markers showed a linear correlation between expression and grade of dysplasia. p16(INK4A) and MCM5 protein expression was upregulated in all grades of squamous and glandular dysplasia. CDC6 protein was preferentially expressed in high grade lesions and in invasive squamous cell carcinoma. CONCLUSION: p16(INK4A) expression was closely associated with high risk HPV infection-all grades of squamous and glandular cervical lesions were immunohistochemically positive. MCM5 staining intensity was independent of high risk HPV infection, highlighting its potential as a biomarker in both HPV dependent and independent cervical dysplasia. CDC6 may be a biomarker of high grade and invasive lesions of the cervix, with limited use in low grade dysplasia. p16(INK4A) was the most reliable marker of cervical dysplasia. Combinations of dysplastic biomarkers may be useful in difficult diagnostic cases.     

Comparative evaluation of nm23 and p16 expression as biomarkers of high-risk human papillomavirus infection and cervical intraepithelial neoplasia 2(+) lesions of the uterine cervix

Benevolo M, Terrenato I, Mottolese M, Marandino F, Muti P, Carosi M, Rollo F, Ronchetti L, Mariani L, Vocaturo G & Vocaturo A
(2010) Histopathology 57 , 580–586
Comparative evaluation of nm23 and p16 expression as biomarkers of high‐risk human papillomavirus infection and cervical intraepithelial neoplasia 2⁺ lesions of the uterine cervix Aims: To investigate the clinical role of nm23 expression in identifying both high‐risk human papillomavirus (HR‐HPV) and high‐grade cervical lesions or carcinomas [cervical intraepithelial neoplasia 2⁺ (CIN2⁺)], and to compare it with p16 overexpression, as this latter biomarker has already been reported widely in HR‐HPV infected cervical lesions. Methods and results: Immunohistochemical evaluation of nm23 and p16 in 143 cervical biopsy specimens including negative, low‐ and high‐grade lesions and squamous carcinomas (SC). HR‐HPV testing by Digene hybrid capture 2 (HC2) and polymerase chain reaction (PCR) on the cervico‐vaginal samples of the same patients. In detecting CIN2⁺, p16 was significantly more sensitive and specific than nm23 (96.3% versus 81.8% and 66% versus 36.4%, respectively, both P < 0.0001). Concerning HR‐HPV detection by HC2, p16 showed a significantly higher specificity than nm23 (82% versus 47%, P <0.0001), although the sensitivities were comparable (71% versus 76%). We found a significantly direct correlation between nm23 and HC2 findings. However, nm23 expression did not correlate with HPV16/18 infection. In contrast, we observed a significant association between p16 overexpression and HPV16/18 genotypes. Conclusions: We confirm the diagnostic value of p16 overexpression. Moreover, despite in vitro data regarding the interaction with the HPV‐E7 protein, nm23 does not appear to be a more useful biomarker than p16 in identifying CIN2⁺ or HR‐HPV infection.     

Diagnostic value of HMGB1 immunostaining on cell blocks from residual liquid‐based gynecologic cytology specimens

Aberrant expression of high mobility group box 1 (HMGB1) is associated with tumor development and progression. The current study was conducted to evaluate the significance of HMGB1 immunostaining on cell block (CB) preparations in the diagnosis of neoplastic and preneoplastic lesions of the cervix. The CBs were prepared from 157 residual liquid‐based gynecologic cytology specimens which were collected from women whose cervical lesions had been confirmed by histopathology. The expression of HMGB1 and p16INK4A (p16) was visualized by immunocytochemistry on the CB preparations, and the association of their expression patterns was correlated with the severity of cervical lesions. HeLa cells were used as positive control. HMGB1 expression was observed in dysplastic and neoplastic cells and increased along with the progression of cervical neoplasia. The rates of positive staining for HMGB1 in cervical intraepithelial neoplasia 1 (CIN‐1), CIN‐2, CIN‐3, and invasive squamous cell carcinomas (ISCCs) were 69.4, 96.9, 100.0, and 100.0%, respectively. The differences between positive rates of patients with chronic cervicitis and various CINs as well as ISCCs were significant (P < 0.005). The differences in positive staining rates between each two CIN groups, and differences between CIN‐1/2 and ISCCs, were also significant (P < 0.005). The expression pattern of HMGB1 was generally correlated with that of p16 (P < 0.001). HMGB1 staining was observed in some p16‐negative specimens. HMGB1 immunostaining on a CB from gynecologic cytology specimens is potentially valuable for the screening of cervical lesions in cases with questionable cytology. Diagn. Cytopathol. 2014;42:802–808. © 2014 Wiley Periodicals, Inc.     

Human papillomavirus genotyping by oligonucleotide microarray and p16 expression in uterine cervical intraepithelial neoplasm and in invasive carcinoma in Korean women

For evaluating the diagnostic significance of p16(INK4A) over-expression in the uterine cervical intraepithelial neoplasm and in invasive carcinoma, human papillomavirus (HPV) was detected and genotyped by oligonucleotide microarray in archival tissues of 117 cervical specimens, including 47 invasive squamous cell carcinomas (SCC), 30 cases of cervical intraepithelial neoplasia (CIN), 20 adenocarcinomas, and 20 cases of non-neoplastic cervix. The expression of p16(INK4A) protein was immunohistochemically studied in these cases and in five HPV-positive and one HPV-negative cervical cancer cell lines. HPV was detected in 50% of CIN, 61.7% of SCC, and 45.5% of adenocarcinomas. p16(INK4A) expression was seen in all 20 cases of adenocarcinoma, 78.7% (37/47) of SCC, and 96.7% (29/30) of CIN, but not in any cases of the non-neoplastic cervix. There was no difference in p16(INK4A) expression between the HPV-positive and HPV-negative cervical lesions. All HPV-positive and -negative cervical cancer cell lines expressed p16(INK4A) protein. In conclusion, the presence of p16(INK4A) expression in cervical squamous and glandular epithelium indicates the existence of dysplasia or malignancy in the uterine cervix, regardless of HPV infection.     

Estimation of prognoses for cervical intraepithelial neoplasia 2 by p16INK4a immunoexpression and high-risk HPV in situ hybridization signal types

The present study used immunohistochemical staining and in situ hybridization (ISH) to examine whether progression of cervical intraepithelial neoplasia, grade 2 (CIN 2) can be predicted by p16INK4a immunoexpression and high-risk human papilloma virus (HPV) ISH signal types. We studied 52 cases histologically diagnosed with CIN 2: dysplasia regressed in 28 cases; 13 cases progressed to CIN 3; and CIN 2 persisted in 11 cases. Expression of p16INK4a and high-risk HPV signal both related to grade of CIN. Stronger p16INK4a immunoexpression and a higher frequency of expression of a punctate nuclear signal were observed in CIN 2 lesions before progression compared with those before regression. CIN 2 cases in which moderate to strong immunoexpression of p16INK4a and a punctate signal were observed simultaneously progressed to CIN 3 in 10 (91%) of 11 cases. CIN 2 cases with moderate to strong immunoexpression of p16INK4a and a high-risk HPV punctate signal should be treated because of the great risk of progression.     

P16(INK4a) expression as a potential prognostic marker in cervical pre-neoplastic and neoplastic lesions

An immunohistochemical analysis with monoclonal antibody p16(INK4a) was performed in formalin-fixed, paraffin-embedded samples of 60 cases. The aim was to investigate in biopsies the expression of p16(INK4a) of normal uterine cervical tissue, pre-cancerous and cancerous lesions, and their relation with human papilloma virus (HPV) and HIV status. Three parameters were evaluated: percentage of p16(INK4a) positive cells, reaction intensity, and cell staining pattern. All of these parameters were statistically different when compared among different histological groups. However, logistic regression model showed that the reaction intensity was the best indicator of the expression of p16(INK4a). This expression increases from normal to invasive squamous carcinoma. Sixty-six percent of the patients with CIN grade 1 (CIN1) expressed p16(INK4a) (all these cases were infected with high risk HPV). Our study supports the hypothesis that p16(INK4a) expression in pre-cancerous lesions and cancers can be used to identify HPV-transformed cells. Of great interest for routine diagnostic use is the fact that immunohistochemical testing for p16(INK4a) seems to be capable of identifying HPV-positive cells and potentially recognizing those lesions with an increased risk of progression to high-grade lesions.     

Clinicopathological Implications of Human Papilloma Virus (HPV) L1 Capsid Protein Immunoreactivity in HPV16-Positive Cervical Cytology

Background: The objective of this study was to investigate the expression of human papilloma virus (HPV) L1 capsid protein in abnormal cervical cytology with HPV16 infection and analyze its association with cervical histopathology in Korean women.Material and Methods: We performed immunocytochemistry for HPV L1 in 475 abnormal cervical cytology samples from patients with HPV16 infections using the Cytoactiv^® HPV L1 screening set. We investigated the expression of HPV L1 in cervical cytology samples and compared it with the results of histopathological examination of surgical specimens.Results: Of a total of 475 cases, 188 (39.6%) were immunocytochemically positive and 287 (60.4%) negative for HPV L1. The immunocytochemical expression rates of HPV L1 in atypical squamous cells of unknown significance (ASCUS), low-grade squamous intraepithelial lesions (LSIL), high-grade squamous intraepithelial lesions (HSIL), and cancer were 21.8%, 59.7%, 19.1%, and 0.0%, respectively. LSIL exhibited the highest rate of HPV L1 positivity. Of a total of 475 cases, the multiple-type HPV infection rate, including HPV16, in HPV L1-negative cytology samples was 27.5%, which was significantly higher than that in HPV L1-positive cytology samples (p = 0.037). The absence of HPV L1 expression in ASCUS and LSIL was significantly associated with high-grade (≥cervical intraepithelial neoplasia [CIN] 2) than low-grade (≤CIN1) histopathology diagnoses (p < 0.05), but was not significantly different between HPV16 single and multiple-type HPV infections (p > 0.05). On the other hand, among 188 HPV L1-positive cases, 30.6% of multiple-type HPV infections showed high-grade histopathology diagnoses (≥CIN3), significantly higher than the percentage of HPV16 single infections (8.6%) (p = 0.0004)Conclusions: Our study demonstrates that the expression of HPV L1 is low in advanced dysplasia. Furthermore, the absence of HPV L1 in HPV16-positive low-grade cytology (i.e., ASCUS and LSIL) is strongly associated with high-grade histopathology diagnoses. The multiplicity of HPV infections may have an important role in high-grade histopathology diagnoses (≥CIN3) in HPV L1-positive cases.