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Objectives: We aim to propose a modified surveillance strategy using a novel blood assay that detects plasma circulating tumor-specific HPV DNA with reported 100% NPV and 94% PPV as the main method of detection to understand the cost implications of potentially avoiding routine imaging and surveillance visits at our institution., Methods: We performed a retrospective chart review focusing on recurrences in p16+ patients with OPSCC and defined two surveillance strategies: "Strategy A", follow-up visits with flexible laryngoscopy (FL) plus regular imaging studies; "Strategy B", follow-up visits with FL plus regular NavDx assays and imaging used at the discretion of the physician(s) in cases of high clinical suspicion., Results: Of the p16+ OPSCC patients (n = 214), 23 had confirmed recurrence (11%). Standard work-flow model determined 72 imaging studies and 2198 physical examinations with FL were needed to detect one recurrence. Potential individual patient cost reduction during surveillance was 42%., Conclusion: Implementing NavDx for HPV + OPSCC surveillance would benefit patients by reducing costs and unnecessary diagnostic testing., Level of Evidence: Step/Level 3 Laryngoscope, 133:3006-3012, 2023., (© 2023 The Authors. The Laryngoscope published by Wiley Periodicals LLC on behalf of The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The increase of the incidence of human papillomavirus dependent oropharyngeal squamous cell carcinoma is alarming, although we have greatly progressed in the classification and staging of this disease. We now know that human papillomavirus related oropharyngeal squamous cell carcinoma is a sub-type of head and neck squamous cell carcinoma with favourable prognosis and good response to therapy that needs a proper system of classification and staging. Thus, in routine practice it is essential to test patients for the presence of human papillomavirus. The most popular technique to assess human papillomavirus status is immunohistochemistry on biopsy samples with p16, which is an excellent surrogate for high-risk human papillomavirus infection. Another highly sensitive and specific tissue-based technique for the detection of human papillomavirus is RNAscope In situ hybridization that has a prohibitive cost, limiting its use in routine practice. Radiomics is an artificial intelligence based non-invasive method of computational analysis of computed tomography, magnetic resonance imaging, positron emission tomography, and ultrasound images., Methods: In this review, we summarise the last findings of radiomics applied to human papillomavirus associated oropharyngeal squamous cell carcinoma., Results: A growing body of evidence suggest that radiomics is able to characterise and detect early relapse after treatment, and enable development of tailored therapy of human papillomavirus positive oropharyngeal squamous cell carcinoma., (© 2023 The Authors. Journal of Oral Pathology & Medicine published by John Wiley & Sons Ltd.)

Objective: To evaluate the clinical utility of p16/Ki67 dual-stain (DS) compared with cytology for detecting cervical intraepithelial lesion grade two or worse (CIN2+) in women with a transformation zone type 3 (TZ3)., Design: Cross-sectional study., Setting: Colposcopy clinics in Central Denmark Region., Population: Women aged 45 years or older referred for colposcopy because of an abnormal screening test., Methods: All women had a cervical sample collected for cytology and DS testing and underwent large-loop excision of the transformation zone (LLETZ)., Main Outcome Measure: Sensitivity, specificity and negative (NPV) and positive (PPV) predictive values of DS for CIN2+ detection were compared to those of cytology., Results: Of 166 women eligible, 93 (56.0%) were included in the final analysis. Median age was 68 years (interquartile range [IQR] 63.4-70.5 years). Most women were postmenopausal (95.7%) and referred based on a positive human papillomavirus screening test (86.0%). Fifty-two women (55.9%) were DS-positive, 29 (55.8%) of whom had CIN2+ detected. Twenty-seven (29.0%) women had atypical squamous cells of undetermined significance or worse (ASC-US+), and CIN2+ was detected in 21 women (77.8%). DS had a higher sensitivity (96.7% versus 70.0% p = 0.021) and NPV (97.6% versus 86.4%, p = 0.018) compared with cytology for CIN2+ detection. In contrast, the specificity (63.5% versus 90.5% p < 0.001) and PPV (55.8% versus 77.8%, p = 0.001) were lower for DS compared with cytology., Conclusions: Dual stain may be a valuable risk marker to guide clinical management of women with a TZ3. The superior NPV of DS suggests that a diagnostic excision may safely be avoided in DS-negative women., (© 2022 The Authors. BJOG: An International Journal of Obstetrics and Gynaecology published by John Wiley & Sons Ltd.)

Human papillomaviruses (HPV) are involved in approximately 5% of solid cancers worldwide. The mucosotropic genotypes infect the stratified epithelium of various locations, where persistent infection may lead to invasive carcinomas. While the causative role of HPV in certain anogenital and head and neck carcinomas is well established, the role of HPV in carcinomas arising in the mucosal membranes of the ocular adnexal tissue (the lacrimal drainage system and the conjunctiva) has been a topic of great uncertainty. Therefore, we conducted a series of studies to assess the correlation between HPV and carcinomas arising in the mucosa of the ocular adnexal tissue and characterize the clinical, histopathological, and genomic features of the tumors in the context of HPV status in a Danish nationwide cohort. We collected clinical and histopathological data and tumor specimens from patients with carcinomas of the conjunctiva and the lacrimal drainage system, and their potential precursors, identified in Danish nationwide registries. The HPV status of the tumors was determined by the combined use of HPV DNA polymerase chain reaction (PCR), HPV E6/E7 mRNA in-situ hybridization, and p16 immunohistochemistry. The genomic profile was investigated by high-throughput DNA sequencing targeting 523 cancer-relevant genes. The literature to date on carcinomas of the lacrimal drainage system and the conjunctiva was summarized. In the Danish cohort, 67% of all carcinomas of the lacrimal drainage system and 21% of all conjunctival carcinomas were HPV-positive. HPV16 was the most frequently implicated genotype. A full-thickness expression of the viral oncogenes E6 and E7 was evident in almost all HPV DNA-positive cases. The HPV-positive carcinomas of the conjunctiva and the lacrimal drainage system shared histopathological and genomic features distinct from their HPV-negative counterparts. The HPV-positive carcinomas were characterized by a non-keratinizing morphology, p16 overexpression, high transcriptional activity of HPV E6/E7, and frequent pathogenic variants in the PI3K-AKT signaling cascade. In contrast, the HPV-negative carcinomas were characterized by a keratinizing morphology, lack of p16 and E6/E7 expression, and frequent somatic pathogenic variants in TP53, CDKN2A, and RB1. Among the patients with conjunctival tumors, HPV positivity was associated with a younger age at diagnosis and a higher risk of recurrence. In conclusion, the results support an etiological role of HPV in a subset of conjunctival and LDS carcinomas and their precursor lesions. Our investigations have shown that the HPV-positive carcinomas of the ocular adnexa share genomic and phenotypic characteristics with HPV-positive carcinomas of other anatomical locations. Therefore, these patients may be eligible for inclusion in future basket trials and future treatment regimens tailored to the more frequently occurring HPV-positive carcinomas of other locations. Future research will further elucidate the diagnostic, prognostic, and predictive role of HPV in these carcinomas., (© 2022 The Author. Acta Ophthalmologica published by John Wiley & Sons Ltd on behalf of Acta Ophthalmologica Scandinavica Foundation.)

Objective: To analyze the patterns, risk factors, and salvage outcomes for locoregional recurrences (LRR) after treatment with transoral robotic surgery (TORS) for HPV-associated oropharyngeal squamous cell carcinoma (HPV+ OPSCC)., Study Design: Retrospective analysis of HPV+ OPSCC patients completing primary TORS, neck dissection, and NCCN-guideline-compliant adjuvant therapy at a single institution from 2007 to 2017., Methods: Features associated with LRR, detailed patterns of LRR, and outcomes of salvage therapy were analyzed. Disease-free survival (DFS) and overall survival (OS) were calculated for subgroups of patients receiving distinct adjuvant treatments., Results: Of 541 patients who completed guideline-indicated therapy, the estimated 5-year LRR rate was 4.5%. There were no identifiable clinical or pathologic features associated with LRR. Compared to patients not receiving adjuvant therapy, those who received indicated adjuvant radiation alone had a lower risk of LRR (HR 0.28, 95% CI [0.09-0.83], P = .023), but there was no difference in DFS (P = .21) and OS (P = .86) between adjuvant therapy groups. The 5-year OS for patients who developed LRR was 67.1% vs. 93.9% for those without LRR (P < .001). Patients who initially received adjuvant chemoradiation and those suffering local, in-field, and/or retropharyngeal node recurrences had decreased disease control after salvage therapy., Conclusion: LRR rates are low for HPV+ OPSCCs completing TORS and guideline-compliant adjuvant therapy. Patients without indication for adjuvant therapy more often suffer LRR, but these recurrences are generally controllable by salvage therapy. Improved understanding of the patterns of recurrence most amenable to salvage therapy may guide treatment decisions, counseling, and adjuvant therapy de-escalation trials., Level of Evidence: 3 Laryngoscope, 131:E2865-E2873, 2021., (© 2021 The American Laryngological, Rhinological and Otological Society, Inc.)

Objective: This is an ancillary study of a multi-institutional randomized non-inferiority phase III trial of accelerated fractionation (AF) versus standard fractionation (SF) radiation therapy for T1-2N0M0 glottic cancer (JCOG0701). Biopsy specimens of tumors from the patients enrolled in the JCOG0701 are collected and the association between clinical outcomes and histopathologic features such as expression of epithelial cell adhesion molecule (EpCAM), p53, and p16 were investigated., Methods: Five slices of undyed slides from biopsy specimens were sent to the National Cancer Center Hospital and all the specimens were assessed for the expression of EpCAM, p53, and p16. The primary objective was to investigate the association between 3-year progression-free survival (PFS) and expression of EpCAM, p53, and p16., Results: A total of 88 out of 370 patients were enrolled in this ancillary study. The 3-year PFS for tumors with strong expression of EpCAM was 70.6% (95% CI 43.1%-86.6%), while that of tumors without strong expression of EpCAM was 77.5% (95% CI 65.9%-85.5%) with no remarkable difference between groups (P = .67). Likewise, there was no significant difference in 3-year PFS between tumors regardless of p53 or p16 status. However, in a subgroup analysis for 17 patients with a strong expression of EpCAM, AF showed better 3-year PFS than SF (100% vs 54.5%, P = .07)., Conclusions: From the current study, it could not be concluded that EpCAM, p16, and p53 were prognostic factors for early-stage glottic cancer after primary radiation therapy. AF might be an appropriate fractionation for tumors with a strong expression of EpCAM., Level of Evidence: 3 Laryngoscope, 131:1522-1527, 2021., (© 2020 The American Laryngological, Rhinological and Otological Society, Inc.)

Seborrheic keratosis (SK), actinic keratosis (AK), and Bowen's disease (BD) are squamoproliferative disorders of the skin. Histologically, they may mimic each other and therefore, they might be misinterpreted, especially in small samples. The aim of this study is to clarify the expression of p63, p16, and p53 proteins in SK, AK, and BD and evaluate the efficacy of these markers in order to distinguish between the aforementioned lesions. A total of 46 cases were collected (15 SK, 16 AK, and 15 BD) and stained for p63, p16, and p53. The stain intensity and the cell distribution labeling were scored and then analyzed by SPSS software. All cases of BD which became positive for p53 revealed basal keratinocytes sparing. Instead, all or nearly all basal keratinocytes in AK cases were positive for this marker. These were also seen in p16 staining results and they were between AK and BD (P = .024). Our study demonstrates p16 and p53 are useful markers in separating AK and BD according to basal keratinocytes involvement and sparing, respectively., (© 2021 Wiley Periodicals LLC.)

Background: The separation of benign from malignant mesothelial proliferations on effusion cytology can be difficult. Loss of methylthioadenosine phosphorylase (MTAP) by immunohistochemistry is an established marker of malignancy in mesothelial proliferations, but to the authors' knowledge largely has been applied only to biopsies. The current study was conducted to determine the usefulness of MTAP immunohistochemistry in the diagnosis of malignant mesothelioma in effusion cytology specimens., Methods: A total of 21 effusion cytology cases of malignant mesothelioma were stained for MTAP and BRCA-associated protein 1 (BAP1), with 15 reactive mesothelial cytology cases used as a control. Fourteen cases had a paired surgical specimen for comparison, and 7 cases were run for CDKN2A deletion by fluorescence in situ hybridization., Results: Complete loss of MTAP cytoplasmic staining was noted in 7 of 21 effusion samples (33%), and no loss was observed in 11 effusion samples (52%); 11 of these cases had a matching surgical specimen and all 11 specimens demonstrated the same MTAP pattern. Partial loss was observed in 3 effusion specimens (80%, 40%, and 40% intact staining, respectively), but in all 3 the surgical specimen demonstrated 100% staining. None of the 15 reactive mesothelial cytology specimens demonstrated MTAP cytoplasmic loss. CDKN2A FISH demonstrated concordance in 5 of 7 cases (71%). MTAP immunohistochemistry had a sensitivity of 33% and a specificity of 100% for this differential diagnosis., Conclusions: MTAP staining demonstrated generally good concordance between the cytologic and surgical specimens and appears to be useful in the diagnosis of mesothelioma on effusion specimens. Complete loss of MTAP is a reliable marker of malignancy, but the significance of partial loss of MTAP staining is unclear., (© 2019 American Cancer Society.)

Background: Many patients with human papillomavirus (HPV)-related head and neck squamous cell carcinoma (HPV-HNSCC) initially present with cervical lymph node metastases. Although p16 immunohistochemistry (IHC) is the most commonly used surrogate marker for HPV, however criteria in cytologic material are not well established. The objective of this study was to better characterize p16 IHC in cell blocks of metastatic HPV-HNSCC, and to evaluate the performance of HPV RNA in situ hybridization (RNA ISH)., Methods: p16 IHC was performed on cell blocks from 97 metastatic HPV-HNSCC fine-needle aspiration specimens with HPV status confirmed by DNA or RNA ISH or polymerase chain reaction (PCR). Tumor cellularity (<100 cells, 100-500 cells, and >500 cells) and quality (presence of cell clusters, necrosis) were recorded. p16 staining intensity and extent (1%-9%, 10%-69%, and ≥70%) were scored. In addition, RNA ISH was performed on 38 PCR-positive cases., Results: p16 IHC was positive in 90 of 97 cases (93%), demonstrating variable patterns. p16 staining was found to be moderate to strong in 69 cases, with 37 cases (38%) demonstrating positivity in ≥70% of tumor cells. Weak staining occurred in 21 cases (22%) and 7 cases (7%) were negative. Of the 60 cases with weak and/or absent expression or staining in <70% of cells, 30 cases (50%) had <100 tumor cells, 12 (20%) lacked cell clusters, and 19 cases (32%) had extensive necrosis. RNA ISH was positive in 37 of 38 cases (97%) that were HPV positive by PCR., Conclusions: p16 is heterogeneous in cell blocks of metastatic HPV-HNSCC, suggesting that any p16 positivity should prompt confirmatory HPV studies. RNA ISH appears to demonstrate high sensitivity, and laboratories even may consider using RNA ISH as a first-line HPV test in cytologic specimens., (© 2019 American Cancer Society.)

Background: Fine-needle aspiration (FNA) of a neck mass is frequently the initial diagnostic procedure for patients with human papillomavirus-positive head and neck squamous cell carcinoma. By performing a p16 immunocytochemistry (ICC) stain on FNA material, the pathologist can help to direct the treating physician's search for the primary site and to select the proper management for the patient. There is currently no established threshold for the evaluation of p16 ICC in cytology samples. This study was aimed at establishing an optimal threshold for p16 ICC interpretation in cytology samples., Methods: The pathology databases were searched for all neck-mass FNAs diagnosed as squamous cell carcinoma from January 2010 to March 2019. p16 ICC was performed on cytology smears, and the percentage and intensity of p16-positive cells were assessed. Receiver operating characteristic (ROC) curves were plotted to determine the best cutoff threshold for p16 positivity on cytology smears., Results: p16 ICC was performed on 50 cytology smears. An analysis of 8 different thresholds (combinations of the percentage and intensity of the p16 stain) using ROC curves demonstrated the best threshold to be 50% p16 staining with a sensitivity of 74% and a specificity of 100%. Applying the threshold used for surgical specimens (70%) to cytology samples resulted in a low sensitivity (45%)., Conclusions: p16 ICC on cytology smears shows diminished staining in comparison with surgical samples. Using 50% staining as the cutoff to consider positivity for p16 in cytology smears is proposed to decrease false-negative results while maintaining specificity., (© 2019 American Cancer Society.)

Background: The p16 immunohistochemical (IHC) marker has been used increasingly as an adjunct to morphologic assessment of cervical biopsies in which the differential diagnoses include high-grade squamous intraepithelial lesion (HSIL) and its mimics. The objective of this study was to assess the potential influence of p16 IHC staining on the evaluation of cervical biopsy as observed through cytologic-histologic correlation (CHC)., Methods: Cervical biopsy samples that had cytologic diagnoses of either low-grade squamous intraepithelial lesion (LSIL) or HSIL and also had histologic follow-up were retrieved from the department database. CHC and the use of p16 IHC from 2 periods (group 1, 2008; group 2, 2014-2016) were compared and analyzed., Results: Histology on 452 samples from patients who had prior LSIL cytology in group 1 yielded 126 benign (27.9%), 272 LSIL (60.2%), and 54 HSIL (11.9%) diagnoses. By comparison, 491 samples from the patients in group 2 yielded 106 benign (21.6%), 277 LSIL (56.4%), and 108 HSIL (22.0%) diagnoses. The difference in CHC discrepancies between the 2 groups was significant (P = .0001), mainly because of the increased diagnosis of HSIL in group 2. Although p16 IHC was not applied to any sample from group 1, it was performed on 141 of 491 samples (28.7%) from group 2. Further follow-up of patients who had histologic HSIL revealed that residual HSIL was identified significantly more often in those who did not have p16 IHC applied in the preceding cervical biopsy than in those did (P = .0004). A similar comparison was performed between 113 patients from group 1 and 152 patients from group 2 who had a prior diagnosis of HSIL cytology, and the difference was statistically insignificant., Conclusions: The use of p16 IHC on cervical biopsies in patients who had a prior cytologic diagnosis of LSIL may lead to greater detection and upgrading of HSIL, thereby compounding the discrepancy in CHC., (© 2018 American Cancer Society.)

Objectives: To examine combined immunoprofiles of epidermal growth factor receptor (EGFR), CD44, and p16 in oropharyngeal squamous cell carcinoma (OPSCC) and to correlate them with radiotherapy treatment outcomes and clinicopathological parameters. Prognostic impact of the American Joint Committee on Cancer (AJCC) 8th edition staging system in comparison with 7th edition was analyzed., Methods: The study included 77 OPSCC patients treated by definitive intensity-modulated radiotherapy (IMRT). Clinical staging was assessed according to the AJCC, both 7th and 8th edition. Immunohistochemical (IHC) analysis of CD44 and EGFR was performed on primary biopsy tumor tissues. To evaluate the HPV status, IHC detection of p16 was employed., Results: The AJCC 8th edition staging system revealed correlations between overall survival (OS), progression-free survival (PFS), locoregional control (LRC), and clinical stage. EGFR and CD44 positivity (+) and p16 negativity (-) were associated with clinical stage IV of the disease. CD44+ and EGFR+ OPSCC displayed worse OS and LRC, and these cases also showed the worst 3-year OS and LRC. Combined analysis of protein expressions identified an association between p16- and EGFR+, p16- and CD44+, EGFR+, and CD44+. Combined immunoprofiles CD44+/p16-, EGFR+/p16-, and EGFR+/CD44+ were associated with worst OS and LRC., Conclusions: Combined immunoprofiles of p16, EGFR, and CD44 might provide valuable prognostic and predictive information for the individual OPSCC patients, especially in terms of response to IMRT and prediction of treatment outcomes. Application of the AJCC 8th edition staging for HPV+ OPSCC proved to improve hazard discrimination and prognostication of OPSCC., (© 2018 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives/hypothesis: Consulting of patients with oropharyngeal carcinoma, classified as pT1pN1cM0 and pT2p/cN0cM0, about postoperative radiotherapy is a precarious task as data are lacking. The aim of this study was to evaluate the effects of postoperative radiotherapy for patients with intermediate-stage oropharyngeal carcinoma., Study Design: Multicentric retrospective study., Methods: This analysis was conducted at seven Austrian institutions and included data of patients treated between 2000 and 2012. A total of 81 patients with oropharyngeal squamous cell carcinoma were included, of whom 33 patients received postoperative radiotherapy. p16 status determined by immunohistochemistry was available in 68 patients., Results: Median follow-up was 47.9 months. Postoperative radiotherapy showed no benefits in regard to overall survival (P = .701). In contrast, disease-free survival was significantly shortened in all patients without postoperative radiotherapy (P = .001). When dividing the cohort in dependence of p16, p16-positive patients did not benefit from postoperative radiotherapy regarding overall and disease-free survival (P = .934 and P = .102), whereas p16-negative patients showed improved disease-free survival after postoperative radiotherapy (P = .007). Multivariate analysis showed that outcome of postoperative radiotherapy is dependent on p16 status., Conclusions: In terms of disease-free survival, patients with p16-negative tumors may benefit from postoperative radiotherapy, whereas survival of p16-positive patients is good regardless of additional treatment., Level of Evidence: 4. Laryngoscope, 128:1075-1082, 2018., (© 2017 The American Laryngological, Rhinological and Otological Society, Inc.)

Background: The aim of this study was to identify the presence and frequency of human papillomavirus (HPV) nucleic acid in p16-positive oral squamous cell carcinomas (OSCCs), to assess whether the virus was transcriptionally active and to assess the utility of p16 overexpression as a surrogate marker for HPV in OSCC., Methods: Forty-six OSCC patients treated between 2007 and 2011 with available formalin-fixed paraffin-embedded (FFPE) specimens were included. Twenty-three patients were positive for p16 by immunohistochemistry (IHC) and these were matched with 23 patients with p16-negative tumours. Laser capture microdissection of the FFPE OSCC tissues was undertaken to isolate invasive tumour tissue. DNA was extracted and tested for high-risk HPV types using a PCR-ELISA method based on the L1 SPF10 consensus primers, and a real-time PCR method targeting HPV-16 and HPV-18 E6 region. Genotyping of HPV-positive cases was performed using a reverse line blot hybridization assay (Inno-LiPA). RNAScope ® (a chromogenic RNA in situ hybridization assay) was utilized to detect E6/E7 mRNA of known high-risk HPV types for detection of transcriptionally active virus., Results: HPV DNA was found in 3 OSCC cases, all of which were p16 IHC-positive. Two cases were genotyped as HPV-16 and one as HPV-33. Only one of the HPV-16 cases was confirmed to harbour transcriptionally active virus via HPV RNA ISH., Conclusion: We have shown that the presence of transcriptionally active HPV rarely occurs in OSCC and that p16 is not an appropriate surrogate marker for HPV in OSCC cases. We propose that non-viral mechanisms are responsible for the majority of IHC p16 overexpression in OSCC., (© 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Oral submucous fibrosis (OSF) is a chronic progressive disease of the oral cavity that is considered a common potentially malignant disorder in South Asia. Areca nut chewing is the main etiological factor, but its carcinogenic mechanism has yet to be proven. The purpose of this study was to identify the useful biomarkers in predicting high-risk patients with OSF., Methods: Thirty-six cases of OSF and six cases of normal oral mucosa (NOM) were used for this study. Immunohistochemical staining was performed for Ki67, cyclin D1, p16, p53, β-catenin, c-Jun, c-Met, and insulin-like growth factor II mRNA-binding protein 3 (IMP3). The expression patterns of NOM served as guidelines for the scoring system., Results: The expression of Ki67, cyclin D1, c-Met, IMP3, and β-catenin showed a significant difference between OSF and NOM samples. The combined biomarkers of Ki67 and p16 showed significantly different expression between the transformation and non-transformation groups. With discriminant analysis, we proposed a noble formula and cutoff value for predicting high-risk patients with OSF., Conclusion: The notable biomarkers in our present study were Ki67 and p16 showing significantly different expression levels between the transformation and non-transformation groups. With the identification of high-risk patients with OSF, we can expect to develop more intensive treatment modalities, leading to the reduction in cancer transformation rate from OSF., (© 2016 The Authors. Journal of Oral Pathology & Medicine Published by John Wiley & Sons Ltd.)

Background: More accurate biomarkers in cervical cytology screening could reduce the number of women unnecessarily referred for biopsy. This study investigated the ability of p16/Ki-67 dual staining to predict high-grade cervical intraepithelial neoplasia (CIN) in human papillomavirus (HPV)-positive women from the Norwegian Cervical Cancer Screening Program., Methods: Automated p16/Ki-67 dual staining was performed on liquid-based cytology samples from 266 women who were HPV-positive at their secondary screening. At a mean of 184 days after p16/Ki-67 staining, 201 women had a valid staining result and a conclusive follow-up diagnosis (histological diagnosis or HPV-negative diagnosis with normal cytology findings). The sensitivity and specificity for predicting the follow-up diagnosis were compared for cytology, p16/Ki-67 dual staining, and their combination., Results: Sixty-seven percent of the study sample was p16/Ki-67-positive. The sensitivity of p16/Ki-67 staining for predicting CIN-2/3 was statistically significantly higher than the sensitivity of cytology (0.88 vs 0.79; P = .008), but this was not true for the prediction of CIN-3 (0.94 vs 0.88; P = .23). The specificity of cytology for predicting CIN-3 was significantly higher than the specificity of p16/Ki-67 staining (0.35 vs 0.28; P = .002), but this was not true for CIN-2/3 (0.35 vs 0.31; P = .063). For predicting CIN-2/3 and CIN-3, combination testing gave potentially better sensitivity (0.95 and 0.96, respectively) and better specificity (0.49 and 0.50, respectively)., Conclusions: In a population of HPV-positive women, p16/Ki-67 dual staining was more sensitive but less specific than cytology for predicting high-grade CIN. The advantage of using both tests in different combinations is the potential for increasing the specificity or sensitivity in comparison with both methods performed individually. Cancer Cytopathol 2017;125:283-291. © 2016 American Cancer Society., (© 2016 American Cancer Society.)

Background: The accumulation of cyclin-dependent kinase inhibitor 2A (p16 ink4a ) protein in a cell is associated with neoplastic progression in precancerous cervical lesions. Dual staining for p16 ink4a and Ki-67 has been proposed as a triage test in cervical cancer screening for women who test positive for human papillomavirus DNA. In this study, interobserver reproducibility of the interpretation of this test was assessed., Methods: Forty-two immunostained, liquid-based cytology slides were divided into 2 sets and were interpreted by 17 to 21 readers from 9 different laboratories, yielding a total of 816 reports. Immunostaining results were classified as positive, negative, inconclusive, or inadequate. After evaluation of the first set of slides and before circulation of the second set, the results were discussed in a plenary meeting. The 10 slides with the most discordant results were evaluated again by selected expert cytopathologists., Results: The overall κ value was 0.612 (95% confidence interval [CI], 0.523-0.701), it was higher for the positive and negative categories (κ = 0.692 and κ = 0.641, respectively), and it was almost null for the inconclusive category (κ = 0.058). Considering only readers from laboratories with documented experience, the κ value was higher (κ = 0.747; 95% CI, 0.643-0.839) compared with nonexperienced centers (κ = 0.498; 95% CI, 0.388-0.616). The results were similar in both sets of slides (κ = 0.505 [95% CI, 0.358-0.642] and κ = 0.521 [95% CI, 0.240-0.698] for the first and second sets, respectively). Reinterpretation of the slides with the most discordant results did not provide any improvement (first evaluation, κ = 0.616 [95% CI, 0.384-0.866]; second evaluation, κ = 0.403 [95% CI, 0.182-0.643])., Conclusions: Dual staining for p16 ink4a and Ki-67 demonstrated good reproducibility, confirming its robustness, which is a necessary prerequisite for its adoption as a triage test in cervical cancer screening programs that use human papillomavirus DNA as a primary test. Cancer Cytopathol 2017;125:212-220. © 2016 American Cancer Society., (© 2016 American Cancer Society.)

Background: Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) is a unique form of carcinoma that is important to identify for prognosis and treatment. Immunohistochemistry (IHC) for p16 (also known as cyclin-dependent kinase inhibitor 2A, multiple tumor suppressor 1) is used as a surrogate marker for transcriptionally active, high-risk HPV. The primary objective of this study was to correlate p16 IHC of cell blocks from fine-needle aspirations (FNAs) with surgical pathology specimens of HPV-related oropharyngeal SCC., Methods: In total, 48 patients who had a diagnosis of oropharyngeal or nonoropharyngeal SCC and also had an FNA that demonstrated metastatic SCC with available cell block material were identified. IHC for p16 was evaluated on both FNA cell blocks and surgical pathology specimens. In situ hybridization for high-risk HPV messenger RNA was performed on 31 of the FNA cell blocks., Results: Although partial p16 staining was observed in the majority of cell blocks, there was concordance in 47 of 48 FNAs (98%) with surgical pathology specimens when strong positive p16 staining of at least 15% of tumor cells in FNA cell block material was present. In addition, high-risk HPV RNA in situ hybridization demonstrated a high correlation with p16 staining in surgical pathology specimens (96%) and FNAs (93%)., Conclusions: There was excellent correlation between p16 IHC of FNA cell blocks and surgical pathology specimens using a cutoff of at least 15% positive staining in cell blocks. The recommended threshold (70% positive staining) for surgical pathology specimens may yield a high rate of false-negative results if applied to FNA cell blocks., (© 2015 American Cancer Society.)

Background: The recent epidemic of head and neck squamous cell carcinomas associated with human papilloma virus (HPV) has not addressed its association with lymphoid tissue in the oropharynx or the potential role of Epstein-Barr virus (EBV)/HPV coinfection., Methods: The prevalence of HPV and EBV infection/coinfection and CD21 mRNA expression were determined in normal and cancerous tissues from the oropharynx using in situ hybridization (ISH), p16, and quantitative reverse transcriptase PCR (qRT-PCR). The effects of coinfection on tumorigenicity were evaluated using proliferation and invasion assays., Results: Normal oropharynx, tonsil, non-cancer base of tongue (BOT), and BOT from sleep apnea patients demonstrated EBV positivity ranging from 7% to 36% depending on the site and methods of detection used (qRT-PCR or ISH). Among non-malignant BOT samples, HPV positivity was noted only in 20%. The percent of tonsil and BOT cancers positive for HPV (up to 63% and 80%, respectively) or coinfected with HPV/EBV (up to 25% and 70%, respectively) were both significantly associated with cancer status. Notably, HPV/EBV coinfection was observed only in malignant tissue originating in lymphoid-rich oropharynx sites (tonsil, BOT). CD21 mRNA (the major EBV attachment receptor) was detected in tonsil and BOT epithelium, but not in soft-palate epithelium. Coinfected cell lines showed a significant increase in invasiveness (P < 0.01)., Conclusions: There is a high prevalence of HPV/EBV infection and coinfection in BOT and tonsil cancers, possibly reflecting their origins in lymphoid-rich tissue. In vitro, cells modeling coinfection have an increased invasive potential., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Localized juvenile spongiotic gingival hyperplasia (LJSGH) is a distinct type of gingival hyperplastic lesion with specific clinicopathologic features. Evaluation of the morphological characteristics of LJSGH indicates the potential role of human papillomavirus (HPV) infection as an underlying etiopathogenetic mechanism., Methods: All cases of LJSGH from 2008 to present were retrieved. Clinical and demographic data were collected. HPV status was investigated by p16INK4A immunohistochemistry and HPV-Polymerase chain reaction (PCR)., Results: Twenty-one cases of LJSGH were identified, 14 (66.7%) affecting males and seven (33.3%) females (M:F = 2:1, age range: 8-36, mean: 13 years). All lesions were well-demarcated, exophytic, erythematous, and hemorrhagic with granular or slightly papillary surface. Preponderance for the maxillary gingiva (19, 90.5%) was observed. Two (9.5%) patients presented with recurrence 20 and 21 months after excision (mean follow-up: 18.7 months). Histopathologically, all LJSGH lesions featured epithelial hyperplasia with intense neutrophilic exocytosis and spongiosis. All cases demonstrated positivity for p16INK4A with the majority of specimens (47.6%) intensely decorated in >50% of the overlying epithelium with focal immunostaining observed in 47.6% and diffuse in 52.4%. Thirteen cases (61.9%) were negative for HPV DNA by PCR, while two (9.5%) were suspicious for the presence of low levels of HPV DNA but definitive genotyping was not possible. One case (4.8%) displayed positivity for HPV-31. The remaining five cases failed the PCR reaction., Conclusions: Human papillomavirus does not participate in the pathogenesis of LJSGH. P16INK4A expression in the absence of detectable HPV DNA can likely be attributed to the intense inflammation associated with LJSGH., (© 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Background: Human papilloma virus is a risk factor for oropharyngeal cancer. Evidence for a similar aetiological role in the development of oral dysplasia or its transformation to oral cancer is not as clear. Meta-analyses estimate the prevalence of high-risk human papilloma virus (HPV) serotypes to be three times higher in pre-malignant lesions and cancer than in normal oral mucosa. However, this does not imply a causal relationship. Conflicting results are reported from the few studies examining the prognostic significance of HPV positivity in the development of oral cancer. We aimed to examine the ability of p16(INK4a) protein expression, a surrogate marker of HPV infection, to predict malignant progression in a large cohort of oral dysplasia patients., Methods: One hundred forty eight oral dysplasia cases underwent immunohistochemical analysis using a monoclonal antibody against p16(INK4a) . Clinical factors were also collated on each case. Slides were double scored independently by two trained observers. Univariate analyses using both logistic and Cox regression models were performed., Results: Thirty nine of 148 cases progressed to cancer. Ten of 148 cases (7%) were p16(INK4a) positive. High grade of dysplasia (P = 0.0002) and lesion morphology (P = 0.03) were found to be prognostic of malignant progression. p16(INK4a) score was not prognostic in this cohort (P = 0.29). This did not change with a time to event analysis (P = 0.24)., Conclusion: Few studies have assessed the aetiological role of HPV in cancer development from dysplastic lesions. Our study, using one of the largest cohorts of oral dysplasia, demonstrated a low rate of p16(INK4a) positivity and was unable to confirm a prognostic ability for this biomarker., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Objectives: Functional inactivation of p16 is an early and frequent event in the carcinogenesis of tumours of the head and neck region. However, the prognostic relevance of p16 protein expression for these tumours has been controversial. This study aims to examine immunohistochemical expression of p16 and HP virus in a large number of oral carcinomas, and possible correlation with clinical features of the tumours and survival of the patients., Methods: Two tissue microarrays composed of 222 oral carcinomas and 427 squamous cell carcinomas of the head and neck region were used for this study. Sections were stained immunohistochemically (anti-p16), and PCR analysis (HPV status) was carried out. Correlation of p16 expression/HPV status with features of tumours and with survival of the patients was analysed by means of Chi-squared test and using Kaplan-Meier analysis, respectively., Results: p16 expression was found immunohistochemically in 74% of tumours, but was not significantly correlated with features of the tumours, but recurrence-free survival of the patients (P = 0.009) if located predominantly nuclear. On the other hand neither intensity of p16 expression (P = 0.41) nor HPV status (P = 0.82) had any effect on these two aspects., Conclusion: Immunohistochemical expression of p16 alone provides a limited tool for diagnosis and prognosis of carcinomas of the head and neck region. Immunohistochemical analysis of p16 depending on its intracellular location might serve as a surrogate marker for HPV infection., (© 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

Oral lichen planus (OLP) is a common oral mucosal disease, which is generally considered a potentially malignant lesion. To identify efficiently prognostic biomarker, we investigated the microRNA-137 (miR-137) promoter methylation in OLP and compared with the samples from healthy volunteers and patients with oral squamous cell carcinoma (OSCC). A total of 20 OLP and 12 patients with OSCC as well as 10 healthy subjects were subjected to miR-137 promoter methylation analysis using methylation-specific PCR (MSP). To address the malignancy prediction potential from miR-137 promoter methylation status, methylation of the p16 gene, a well-known tumor suppressor, was investigated in the same samples. The p16 methylation and miR-137 promoter methylation were found to be 25% and 35% in patients with OLP, 50% and 58.3% in patients with OSCC, and 0% and 0% in healthy subjects, respectively. The differences between miR-137 and p16 methylation levels were statistically significant between healthy controls and patients. Methylation levels of the two promoters were also influenced by age, gender, and lesion duration. Interestingly, aberrant promoter methylation of the p16 and miR-137 genes was only found in the epithelium but not in the connective tissue from patients with OLP. This raises the possibility to use miR-137 methylation as a biomarker for malignant prediction in patients with OLP., (© 2012 John Wiley & Sons A/S. Published by Blackwell Publishing Ltd.)

Background: Although previous studies have shown that p16(INK4a) and Ki-67 are sensitive and specific markers for high-grade lesions (≥CIN2) on cervical biopsies, limited information is available regarding the performance of a dual-staining approach as a diagnostic adjunct in cervical cytology. We evaluated a dual p16(INK4a)/Ki-67 immunocytochemistry (ICC) assay to determine its sensitivity and specificity versus that of high-risk HPV (HR-HPV) in a US-based pilot cytology study., Methods: ThinPrep specimens from 122 cervical cytology specimens encompassing 23 negative (NILM), 20 ASC-US, 22 LSIL, 17 ASCH, 22 HSIL, and 18AGC cases were processed for multiplexed ICC staining using a CINtec Plus Kit. Dual-positive assay results were defined based on the detection of 1 or more epithelial cells that were stained for both p16INK4a and Ki-67 without regard to cellular morphology. HR-HPV testing was performed by multiplex PCR with capillary electrophoresis genotyping., Results: Dual staining for p16(INK4a) and Ki-67 was frequently detected in HSIL and AGC but was rarely detected in NILM cases. The HR-HPV assay showed a sensitivity of 76.2% and a specificity of 55.8% for the detection of clinically significant cervical squamous or endometrial lesions. In contrast, the colocalization of p16(INK4a) plus Ki-67 maintained a high sensitivity of 81.8% and improved specificity to 81.8% for biopsy-confirmed CIN2/3, endocervical adenocarcinoma, or endometrial adenocarcinoma., Conclusions: Dual staining for p16(INK4a)/Ki-67 immunocytochemistry dramatically increased specificity and maintained high-level sensitivity for the diagnosis of CIN2/3 or glandular lesions compared with PCR-based testing for HR-HPV.

Background: Betel nut chewing, cigarette smoking and alcohol drinking are thought to be major environmental risk factors responsible for the development of oral squamous cell carcinomas. Oncogenic human papillomavirus infections have a well-established association with uterine cervical carcinoma. However, little is known about the exact role of human papillomavirus infections in oral squamous cell carcinomas. This study is designed to elucidate the role of human papillomavirus infections in cancer development and prognosis of oral squamous cell carcinomas., Methods: Molecular techniques including in situ hybridization and immunohistochemistry of p16(INK4A) and p53 for evidences of human papillomavirus in tissue micro-arrays were investigated., Results: Twenty-four of 65 cases of oral squamous cell carcinomas were found positive for in situ hybridization and 14 were found positive for p16(INK4A). The majority of cases without the evidence of human papillomavirus were related to p53 over-expression. There were statistically significant correlations between the results of human papillomavirus test and size or extent of the tumor (P = 0.003) or the stage of oral squamous cell carcinomas (P = 0.015). Kaplan-Meier plot analysis demonstrated a tendency of longer survival in cases of oral squamous cell carcinomas with the evidence of human papillomavirus or positive p16 (INK4A)., Conclusions: Human papillomavirus infections may play a unique role in oral carcinogenesis. Our data strongly suggest that human papillomavirus-positive oral squamous cell carcinomas comprise a distinct clinical and pathological disease entity that appears related to a better outcome with longer survival and bears a causally associated relationship different from other carcinogenic mechanisms., (© 2011 John Wiley & Sons A/S.)

Background: The primary goal of this study was to compare the clinical performance of an optimized and rigorously controlled immunocytochemical (ICC) assay for p16(INK4a) to high-risk (HR) human papillomavirus (HPV) detection by polymerase chain reaction (PCR) as diagnostic adjuncts for cytology specimens from colposcopy patients., Methods: : The study included 403 cervical cytology specimens collected within 3 months of colposcopy. The colposcopic impression and cervical biopsy diagnosis served as the standards for correlation with cytological, p16(INK4a), and HPV data. p16(INK4a) was evaluated using an immunoperoxidase-based assay that was linear over 4 logs for the detection of HeLa-spiked positive control cytology specimens, using a threshold for positive test results that was based on receiver operating characteristic curve analysis. HR-HPV was detected by multiplex PCR using genotype-specific primers., Results: : In all combined diagnostic categories (negative for intraepithelial lesion and malignancy, atypical glandular cells, atypical squamous cells of undetermined significance, atypical squamous cells cannot exclude high-grade squamous intraepithelial lesion, low-grade squamous intraepithelial lesion, and high-grade squamous intraepithelial lesion), the p16(INK4a) ICC and HR-HPV assays, respectively, had sensitivity of 81.7% and 83.3% (P = .81) and specificity of 78.1% and 50.9% (P < .001) for the detection of underlying > or =grade 2 cervical intraepithelial neoplasia (CIN) lesions on biopsy. Furthermore, the positive predictive value of p16(INK4a) ICC was greater than that of HR-HPV for patients with biopsies > or =CIN-2 (41.2% and 24.2%, respectively, P = .001)., Conclusions: : This p16(INK4a) immunocytochemical assay has superior specificity but similar sensitivity to HR-HPV testing to predict underlying high-grade dysplastic lesions in patients who are referred for colposcopy. The determination of the overall performance characteristics of p16(INK4a) immunocytochemistry, as an independent test or in combination with HPV testing in low-risk screening populations, however, will require subsequent large-scale prospective clinical trials., (Copyright 2010 American Cancer Society.)

Background: Expression of p16 has been proposed as a marker for malignant transformation. This study aimed to evaluate p16 expression in oral squamous cell carcinoma (OSCC) and premalignant lesions including oral leukoplakia (OL) with and without dysplasia., Methods: Expression of p16 was investigated in 56 samples including OSCC, OL with and without dysplasia, and normal oral mucosa. Expression of p16 was identified by immunohistochemistry, using the CINtecTM p16INK4a Histology Kit. Both nuclear and/or cytoplasmic staining of the keratinocytes were considered to be positive and the percentage of positive cells was calculated., Results: Expression of p16 was detected in 3/16 (18.75%) cases of OSCC, in 4/15 (26.7%) cases of OL without dysplasia, and in none of OL with dysplasia and normal mucosa. No significant differences in p16 expression prevalence were found among OSCC, OL with and without dysplasia and normal mucosa. The percentages of positive cells in OSCC and OL without dysplasia were 0.89 and 0.17, respectively. No significant difference in the percentage of positive keratinocytes was found., Conclusion: As a marker, p16 is not reliable for oral mucosal dysplasia and malignant transformation.

Background: Local or regional lymph node recurrence is the most common pattern of treatment failure in oral squamous cell carcinoma (SCC). The local recurrence rate is 30% even when the surgical resection margin is diagnosed as tumour free. Accumulation of genetic changes in histologically normal epithelium in the surgical resection margin may explain the local recurrence rate. The purpose of this study is to investigate the presence of senescence markers, which may represent early malignant changes in the margin that in routine pathological evaluations are classified as histologically normal., Methods: Formalin-fixed, paraffin-embedded surgical specimens from 16 consecutive patients with oral SCC and a clear surgical margin were obtained. The margin was analysed by immunohistochemistry for p53, p16, Chk2, Laminin-5 and glycosylated oncofetal fibronectin., Results: Two patterns of p53 expression were found in the histologically normal epithelium in the surgical resection margin. One was characterized by no protein expression in the majority of cells, except for small clusters of basal and parabasal cells with nuclear staining. The other was characterized by p53 expression in the nuclei of most basal cells. The expression of p16 was confined to small groups of cells in the basal cell layer whereas Chk2 was only seen in one case. Upregulation of the stromal proteins, Laminin-5 or glycosylated oncofetal fibronectin, was only seen at regions of invasion., Conclusion: Small groups of cells expressing p53 and p16 were found in the surgical resection margin that appeared to be histologically normal and may represent early malignant changes.

Background: Recurrent respiratory papillomatosis (RRP) is a benign condition that rarely metastasizes as invasive squamous cell carcinoma. Although this disease is associated with human papillomavirus, the role of this virus in tumorigenesis is unclear., Objectives: The aim of this study is to assess the involvement of the tumor suppressors P16INK4A and p53 in RRP tumor progression., Design: Immunohistochemistry of p16INK4A and p53 was performed on biopsies of recurrent squamous papillomas and invasive lesions in nine patients., Results: Twenty biopsies were graded as papillomas (RP), three as papillomas with high-grade dysplasia/carcinoma in situ (HGD/CIS), and two as invasive squamous cell carcinoma (SCCA). Forty-five percent of RP and 60% of HGD/CIS/SCCA expressed p16INK4A. Fifty percent of RP and 100% of HGD/CIS/SCCA expressed p53. The difference in the frequency of p53-positive staining between HGD/CIS and SCCA (100% of tissues examined) and RP (50% of tissues examined) approached statistical significance. Neither p16INK4A nor p53 was predictive of invasive transformation., Conclusions: Expression of p16INK4A, which is a surrogate for the tumor suppressor retinoblastoma (Rb), did not immediately lead to invasive disease. There is no correlation between disease severity of RRP and level of p16INK4A.

Herein, we describe a rare case of giant malignant peripheral nerve sheath tumor of the head in a 38-year-old Japanese man. The tumor measured 210 mm at its largest diameter and was ulcerated, hemorrhagic, multilocular and non-mobile. It should be noted that the patient stubbornly refused to see a doctor for a long time, resulting in the extreme growth of the tumor. We suspect a psychological basis for this behavior. Dermatohistopathological findings of the biopsy indicated ancient schwannoma and total excision was therefore performed. However, after 4 months, the patient developed multiple metastases and died. Post-mortem skin biopsy revealed features of malignant peripheral nerve sheath tumor. We performed immunohistochemical studies on the primary and recurrent lesions and concluded that there was a difference in the expression of Ki67 and p16. We propose that the expressions of Ki67 and p16 should be checked for all lesions of peripheral nerve sheath tumor for distinguishing benign from malignant forms.

Objective: To examine whether depsipeptide (FK228), a histone deacetylase (HDA) inhibitor, has inhibitory effects on the proliferation of synovial fibroblasts from rheumatoid arthritis (RA) patients, and to examine the effects of systemic administration of FK228 in an animal model of arthritis., Methods: Autoantibody-mediated arthritis (AMA) was induced in 19 male DBA/1 mice (6-7 weeks old); 10 of them were treated by intravenous administration of FK228 (2.5 mg/kg), and 9 were used as controls. The effects of FK228 were examined by radiographic, histologic, and immunohistochemical analyses and arthritis scores. RA synovial fibroblasts (RASFs) were obtained at the time of joint replacement surgery. In vitro effects of FK228 on cell proliferation were assessed by MTT assay. Cell morphology was examined by light and transmission electron microscopy. The effects on the expression of the cell cycle regulators p16INK4a and p21(WAF1/Cip1) were examined by real-time polymerase chain reaction and Western blot analysis. The acetylation status of the promoter regions of p16INK4a and p21(WAF1/Cip1) were determined by chromatin immunoprecipitation assay., Results: A single intravenous injection of FK228 (2.5 mg/ml) successfully inhibited joint swelling, synovial inflammation, and subsequent bone and cartilage destruction in mice with AMA. FK228 treatment induced histone hyperacetylation in the synovial cells and decreased the levels of tumor necrosis factor alpha and interleukin-1beta in the synovial tissues of mice with AMA. FK228 inhibited the in vitro proliferation of RASFs in a dose-dependent manner. Treatment of cells with FK228 induced the expression of p16INK4a and up-regulated the expression of p21(WAF1/Cip1). These effects of FK228 on p16INK4a and p21(WAF1/Cip1) were related to the acetylation of the promoter region of the genes., Conclusion: Our findings strongly suggest that systemic administration of HDA inhibitors may represent a novel therapeutic target in RA by means of cell cycle arrest in RASFs via induction of p16INK4a expression and increase in p21(WAF1/Cip1) expression., (Copyright 2004 American College of Rheumatology)

We previously reported that p16 gene deletion is involved in the development and progression of adult T-cell leukaemia/lymphoma (ATLL). To further investigate the significance of this gene in ATLL, we examined its expression status in 63 patients. Samples were analysed at DNA, mRNA and protein levels using real-time polymerase chain reaction (PCR), reverse transcription (RT)-coupled real-time PCR and Western blot respectively. Twenty-four patients (38.1%) were p16 gene negative, and they showed significantly shorter survival than p16-gene-positive patients. The expression of p16 mRNA in p16-gene-positive patients varied greatly, and cells from some patients showed up to several hundredfold higher expression than normal lymphocytes. Surprisingly, among 17 patients examined for p16 protein expression, all four patients with unusually high mRNA lacked p16 protein expression, indicating that p16 protein production in these patients was interrupted at the translational level. Moreover, these patients showed significantly shorter survival than p16-protein-positive patients. These results indicate that the presence of p16 gene and p16 mRNA do not necessarily indicate the production of p16 protein in ATLL, and that loss of p16 protein function is involved in progression of ATLL.

We examined the immunohistochemical expressions of cell-cycle- and apoptosis-related factors to investigate the possible role of these factors in odontogenic keratocyst (OKC). Expression of cyclin D1 and p16 protein was detected in the basal and parabasal cells in lining epithelium of OKCs and was found more frequently in basal cell nevus syndrome (BCNS)-associated OKCs than in primary or recurrent OKCs. Positivity for p21 protein was detected in basal to superficial cells, whereas that for p27 protein was detected in parabasal to superficial cells in lining epithelium of OKCs. DNA topoisomerase IIalpha reacted with nuclei in basal and parabasal cells of the lining epithelium of OKCs, and positive cells were observed in BCNS-associated OKCs significantly more frequently than in primary or recurrent OKCs. Expression of Fas in suprabasal to superficial cells and expression of Fas-L in basal and parabasal cells were detected in lining epithelium of OKCs. Immunoreactivity for caspase-3 was detected in basal to suprabasal or superficial cells in lining epithelium of OKCs. Single stranded (ss)DNA-positive nuclei were detected in superficial cells in lining epithelium of OKCs. Fas was more broadly distributed in BCNS-associated OKCs than in primary OKCs, and ssDNA-positive cells were observed in BCNS-associated OKCs significantly more frequently than in primary or recurrent OKCs. These results suggest that BCNS-associated OKCs might be a distinguishable entity from solitary OKCs.

We have previously described the isolation of primitive, slow-proliferating progenitors from normal, circulating CD34+ cells by using the fluorescent dye 5-6-carboxyfluorescein diacetate succinimidyl ester (CFDA-SE). CFDA-SE(bright) (primitive) and CFDA-SE(dim) (differentiating) cells were isolated following cytokine stimulation on the basis of their different proliferation rates. In the present work we analysed the expression levels of a number of proteins involved with differentiation, proliferation and survival/apoptosis in CFDA-SE(bright)/CD34+/slow-proliferating cells that were previously defined as progenitors capable of differentiating into different lineages. The aim of this work was to gain a better understanding of our model system in order to define some of the important parameters that regulate differentiation in haematopoietic progenitors. GATA-1 and PU.1 RNA levels were similar in freshly isolated (d 0) CD34+ and in CFDA-SE(bright) (bright) cells, whereas they increased in CFDA-SE(dim) (dim) cells. Accordingly, Nm23 was expressed at higher levels in bright cells. Moreover, bright cells had higher p21WAF1/CIP1, p27KIP1 and p16Ink4 protein levels than dim cells. Consistently, Cdc2 and Cdk2 kinase activity was much higher in the dim than in the slower proliferating bright cells. C-myc and p53 levels were higher in bright cells than in d 0 CD34+ and dim cells, and so was Bcl-xL, which followed the trend we have previously described for Bcl-2. Thus, bright cells, despite having a higher proliferation rate than the starting d 0 CD34+ population, have strikingly elevated levels of cyclin-dependent kinase inhibitors, which are likely to also act as inhibitors of differentiation.

Alterations in cell proliferative activity are a common phenomenon in oral carcinogenesis. In this study, the expression of the cell cycle-associated proteins p16, pRb, p53, p27 and Ki-67 were examined by immunohistochemistry in precancerous and cancerous oral lesions, including verrucous carcinomas (VCs). Generally, expression of pRb, p53 and Ki-67 increased according to the cell proliferative activity or tumor progression, but p27 expression showed an inverse relationship. Comparing squamous cell carcinomas (SCCs) with VCs, there was a great difference in expression levels of p27, Ki-67 and p53, which seemed to reflect the different cell proliferative activities of these two tumors. Expression of p16 was low in both dysplasia and SCCs, whereas p16 expression was high in VCs. The high immunohistochemical expression for both p16 and pRb in VC is quite different compared with SCC, which may indicate a possible relationship between VC and human papillomavirus (HPV) infection.

For comparative and quantitative analysis of human cyclin-dependent kinase inhibitor gene expression (CKI; p15INK4B, p16INK4A, p16beta, p18INK4C, p19INK4D, p21WAF1, p27KIP1 and p57KIP2) we set up an RT-PCR assay with a construct termed pCKIquant producing polycompetitive RNA as an internal standard. We demonstrated the reproducibility, accuracy and high sensitivity of the assay in the in vitro model of myeloid leukaemic HL-60 cells. We also showed that the pCKIquant CKI assay is an excellent tool for the assessment of CKI mRNA expression in clinical samples, e.g. single cryostat sections of lymphoma biopsies.