The evolving molecular characterisation, histological criteria and nomenclature of adenoid ameloblastoma as a World Health Organisation tumour type.

Adenoid ameloblastoma (AA) was recently recognised as a separate tumour type in the most recent World Health Organisation (WHO) classification of head and neck tumours. This decision has been considered controversial by several groups, who have described AA as a subtype of ameloblastoma, a hybrid odontogenic tumour or to fall within the spectrum of other recognised odontogenic tumours, including dentinogenic ghost cell tumour and adenomatoid odontogenic tumour. Here we review the reasons for the WHO decision to classify AA as a separate tumour type. We also critique molecular and histological findings from recent reports published since the WHO classification. While acknowledging that the classification of tumours is constantly evolving, the balance of current evidence suggests that AA should remain a distinct tumour type, and not a subtype of ameloblastoma, pending further molecular characterisation.

Mutation detection in saliva from oral cancer patients.

OBJECTIVES: The incidence of head and neck squamous cell carcinoma (HNSCC) continues to increase and although advances have been made in treatment, it still has a poor overall survival with local relapse being common. Conventional imaging methods are not efficient at detecting recurrence at an early stage when still potentially curable. The aim of this study was to test the feasibility of using saliva to detect the presence of oral squamous cell carcinoma (OSCC) and to provide additional evidence for the potential of this approach. MATERIALS AND METHODS: Fresh tumor, whole blood and saliva were collected from patients with OSCC before treatment. Whole exome sequencing (WES) or gene panel sequencing of tumor DNA was performed to identify somatic mutations in tumors and to select genes for performing gene panel sequencing on saliva samples. RESULTS: The most commonly mutated genes identified in primary tumors by DNA sequencing were TP53 and FAT1. Gene panel sequencing of paired saliva samples detected tumor derived mutations in 9 of 11 (82%) patients. The mean variant allele frequency for the mutations detected in saliva was 0.025 (range 0.004 - 0.061). CONCLUSION: Somatic tumor mutations can be detected in saliva with high frequency in OSCC irrespective of site or stage of disease using a limited panel of genes. This work provides additional evidence for the suitability of using saliva as liquid biopsy in OSCC and has the potential to improve early detection of recurrence in OSCC. Trials are currently underway comparing this approach to standard imaging techniques.

Developing and Validating a Multivariable Prognostic-Predictive Classifier for Treatment Escalation of Oropharyngeal Squamous Cell Carcinoma: The PREDICTR-OPC Study.

PURPOSE: While there are several prognostic classifiers, to date, there are no validated predictive models that inform treatment selection for oropharyngeal squamous cell carcinoma (OPSCC).Our aim was to develop clinical and/or biomarker predictive models for patient outcome and treatment escalation for OPSCC. EXPERIMENTAL DESIGN: We retrospectively collated clinical data and samples from a consecutive cohort of OPSCC cases treated with curative intent at ten secondary care centers in United Kingdom and Poland between 1999 and 2012. We constructed tissue microarrays, which were stained and scored for 10 biomarkers. We then undertook multivariable regression of eight clinical parameters and 10 biomarkers on a development cohort of 600 patients. Models were validated on an independent, retrospectively collected, 385-patient cohort. RESULTS: A total of 985 subjects (median follow-up 5.03 years, range: 4.73-5.21 years) were included. The final biomarker classifier, comprising p16 and survivin immunohistochemistry, high-risk human papillomavirus (HPV) DNA in situ hybridization, and tumor-infiltrating lymphocytes, predicted benefit from combined surgery + adjuvant chemo/radiotherapy over primary chemoradiotherapy in the high-risk group [3-year overall survival (OS) 63.1% vs. 41.1%, respectively, HR = 0.32; 95% confidence interval (CI), 0.16-0.65; P = 0.002], but not in the low-risk group (HR = 0.4; 95% CI, 0.14-1.24; P = 0.114). On further adjustment by propensity scores, the adjusted HR in the high-risk group was 0.34, 95% CI = 0.17-0.67, P = 0.002, and in the low-risk group HR was 0.5, 95% CI = 0.1-2.38, P = 0.384. The concordance index was 0.73. CONCLUSIONS: We have developed a prognostic classifier, which also appears to demonstrate moderate predictive ability. External validation in a prospective setting is now underway to confirm this and prepare for clinical adoption.

Adenoid ameloblastoma harbors beta-catenin mutations.

Adenoid ameloblastoma is a very rare benign epithelial odontogenic tumor characterized microscopically by epithelium resembling conventional ameloblastoma, with additional duct-like structures, epithelial whorls, and cribriform architecture. Dentinoid deposits, clusters of clear cells, and ghost-cell keratinization may also be present. These tumors do not harbor BRAF or KRAS mutations and their molecular basis appears distinct from conventional ameloblastoma but remains unknown. We assessed CTNNB1 (beta-catenin) exon 3 mutations in a cohort of 11 samples of adenoid ameloblastomas from 9 patients. Two of the 9 patients were female and 7 male and in 7/9 patients the tumors occurred in the maxilla. Tumors of 4 of these 9 patients harbored CTNNB1 mutations, specifically p.Ser33Cys, p.Gly34Arg, and p.Ser37Phe. Notably, for one patient 3 samples were analyzed including the primary tumour and two consecutive recurrences, and results were positive for the mutation in all three tumors. Therefore, 6/11 samples tested positive for the mutation. In the 6 mutation-positive samples, ghost cells were present in only 2/6, indicating beta-catenin mutations are not always revealed by ghost cell formation. Dentinoid matrix deposition was observed in 5/6 mutation-positive samples and clear cells in all 6 cases. None of the cases harbored either BRAF or KRAS mutations. Beta-catenin immunoexpression was assessed in the samples of 8 patients. Except for one wild-type case, all cases showed focal nuclear expression irrespective of the mutational status. Together with the absence of BRAF mutation, the detection of beta-catenin mutation in adenoid ameloblastomas supports its classification as a separate entity, and not as a subtype of ameloblastoma. The presence of this mutation may help in the diagnosis of challenging cases.

Eosinophilic sialodochitis: An emerging atopic condition.

OBJECTIVE: To report the clinical characteristics of the largest single centre cohort of patients with eosinophilic sialodochitis. METHODS: Analysis of data relating to 37 patients seen in a dedicated multidisciplinary clinic was performed. Demographic, clinical, haematological, cytological, histological and radiological features were collated. Response to trials of allergy treatment was assessed. RESULTS: Thirty-seven patients (30 female, seven male) were identified, 42% of whom were of Afro-Caribbean origin, with a mean age of 50.4 years (range 28-80 years). Mean symptom duration at presentation was 10 years (range 2-33 years). Parotid and submandibular gland involvement was equally reported. The most commonly reported symptoms were swelling (97%), itching of the overlying skin (92%), salivary gland discomfort (84%) and "string-like" mucus discharge from salivary duct orifices (76%). Twenty-three patients (62%) demonstrated atopic disease and serum IgE level elevated in 57%. All 37 patients had eosinophils present in aspirated duct contents samples while raised peripheral eosinophil count was seen in 41%. Anecdotal symptom improvement was reported with antihistamine, antileukotriene or steroid treatment. CONCLUSION: Eosinophilic sialodochitis should be considered in any patient presenting with recurrent salivary gland swelling. Further studies are needed to evaluate treatments directed at a likely allergic pathogenesis.

Oral epithelial dysplasia: Recognition, grading and clinical significance.

Histopathological grading of epithelial dysplasia remains the principal laboratory method for assessing the risk of malignant transformation in oral potentially malignant disorders (OPMDs). Current views on the molecular pathogenesis and histological interpretation of the features of epithelial dysplasia are described, and the use of grading systems for epithelial dysplasia is discussed. Changes to the current 2017 WHO criteria for diagnosis are proposed with emphasis on the architectural features of epithelial dysplasia. The predictive values of three-grade and binary systems are summarised, and categories of epithelial dysplasia are reviewed, including lichenoid and verrucous lesions, keratosis of unknown significance, HPV-associated dysplasia, differentiated and basaloid epithelial dysplasia. The implications of finding epithelial dysplasia in an oral biopsy for clinical management are discussed from the pathologists' viewpoint.

Serial step sections at narrow intervals with immunohistochemistry are required for accurate histological assessment of sentinel lymph node biopsy in oral squamous cell carcinoma.

BACKGROUND: Sentinel lymph node (SLN) biopsy is an accurate staging modality in early oral squamous cell carcinoma (OSCC), but its accuracy relies on labor-intensive histopathology protocols. We sought to determine whether serial step sections with immunohistochemistry (SSSIHC) at narrow intervals of the entire SLN are required to accurately exclude metastasis. METHODS: Consecutive SLN biopsies over a 13-year period were retrospectively evaluated. If the index section was negative for carcinoma, the entire SLN was subjected to SSSIHC at 150 µm intervals. The first section level and total number of section levels to contain carcinoma were recorded. RESULTS: One hundred and eighteen SLN+ from 90 patients were included. SSSIHC upstaged the nodal status in 19.5% of patients. Metastasis was identified in 16.7% and 10.2% beyond section levels 4 and 6, respectively. Among SLNs requiring SSSIHC, 47.5% contained carcinoma in a single section level. CONCLUSION: SSSIHC of the entire SLN at 150 µm intervals are required to identify occult metastasis in OSCC.

TNM 8 staging is a better prognosticator than TNM 7 for patients with locally advanced oral cavity squamous cell carcinoma treated with surgery and post-operative radiotherapy.

PURPOSE: To assess TNM 8 staging in discriminating overall survival (OS) amongst patients with locally advanced oral cavity squamous cell carcinoma (OCSCC) treated with surgery and post-operative radiotherapy (PORT), compared to TNM 7. MATERIAL AND METHODS: Data from OCSCC patients treated with surgery and PORT between January 2010 and December 2018 were reviewed. Demographics, tumour characteristics and treatment response data were collected, and patients staged according to both TNM 7 and TNM 8. OS and disease free survival (DFS) were estimated using the Kaplan Meier method. Univariate and multivariable analyses were conducted for factors affecting OS, DFS and early disease recurrence within 12 months. RESULTS: Overall 172 patients were analyzed. Median follow up was 32 months for all patients and 48 months for surviving patients. TNM 8 staging demonstrated significant stratification of OS and DFS amongst the entire cohort, whereas TNM 7 staging did not. On multivariable analysis, TNM 8 stage, performance status (PS) and a positive surgical margin were prognostic for OS. Looking at disease recurrence within 12 months, TNM 8 stage IVB, presence of lymphovascular invasion (LVSI), younger age and lesser smoking history were predictive factors on multivariable analysis. CONCLUSION: TNM 8 is a good development of its predecessor in terms of predicting survival for patients with locally advanced OCSCC. We have also identified younger age (<60 years) and a smoking history of <10 pack years as risk factors for early disease recurrence, potentially representing a separate biological cohort within OCSCC patients.

Aneuploidy and loss of heterozygosity as risk markers for malignant transformation in oral mucosa.

The ability to predict malignant transformation in oral potentially malignant disorders would inform targeted treatment, provide prognostic information and allow secondary prevention. DNA ploidy and loss of heterozygosity assays are already in clinical use, and loss of heterozygosity has been used in prospective clinical trials. This review appraises published evidence of predictive ability and explores interpretation of heterogeneous studies, with different diagnostic methods, criteria and intention. Both methods have a sound biological foundation and have predictive value independent of dysplasia grading and clinical parameters. The application of these two techniques cannot be directly compared because of differences in expression of results and application to populations of different risk. Predicting malignant transformation accurately on an individual patient basis is not yet possible with either technique. However, they are valuable applications to stratify patients for inclusion in trials, identify the lowest risk patients and exclude risk when biopsy results are indeterminate for dysplasia.

European Laryngological Society position paper on laryngeal dysplasia Part I: aetiology and pathological classification.

PURPOSE OF REVIEW: To give an overview of the current knowledge regarding the aetiology, epidemiology, and classification of laryngeal dysplasia (LD) and to highlight the contributions of recent literature. As most cases of dysplasia occur at the glottic level and data on diagnosis and management are almost exclusively from this location, laryngeal dysplasia in this position paper is taken to be synonymous with dysplasia of the vocal folds. LD has long been recognized as a precursor lesion to laryngeal squamous cell carcinoma (SCC). Tobacco and alcohol consumption are the two single most important etiological factors for the development of LD. There is currently insufficient evidence to support a role of reflux. Although varying levels of human papillomavirus have been identified in LD, its causal role is still uncertain, and there are data suggesting that it may be limited. Dysplasia has a varying presentation including leukoplakia, erythroleukoplakia, mucosal reddening or thickening with exophytic, "tumor-like" alterations. About 50% of leukoplakic lesions will contain some form of dysplasia. It has become clear that the traditionally accepted molecular pathways to cancer, involving accumulated mutations in a specific order, do not apply to LD. Although the molecular nature of the progression of LD to SCC is still unclear, it can be concluded that the risk of malignant transformation does rise with increasing grade of dysplasia, but not predictably so. Consequently, grading systems are inherently troubled by the weak correlation between the degree of the dysplasia and the risk of malignant transformation. The best data on LD grading and outcomes come from the Ljubljana group, forming the basis for the World Health Organization classification published in 2017.

RNA in situ hybridization for human papillomavirus testing in oropharyngeal squamous cell carcinoma on a routine clinical diagnostic platform.

BACKGROUND: The current diagnostic standard for detection of high-risk human papillomavirus (HPV) in oropharyngeal squamous cell carcinoma is via a two-stage algorithm, namely p16 immunohistochemistry followed by HPV DNA in situ hybridization in p16 positive cases. This study evaluated the feasibility of automated RNA in situ hybridization on a clinical platform as a single-step alternative to the two-stage algorithm within a routine diagnostic histopathology setting. METHODS: Thirty-eight cases positive for both p16 and DNA in situ hybridization, 42 p16 negative cases and 20 cases positive for p16 but negative for DNA in situ hybridization were randomly selected. High-risk HPV RNA in situ hybridization was undertaken on all cases on an automated clinical platform. Manufacturer-recommended and on-slide additional p16/HPV positive and negative controls were used. Test quality assurance and diagnostic RNA in situ hybridization were independently assessed by two observers. A consensus diagnosis was reached in the presence of a third observer on discordant cases. All RNA in situ hybridization results were then correlated against p16 and DNA ISH status. RESULTS: Inter-slide RNA in situ hybridization staining variation was observed in control sections. RNA in situ hybridization demonstrated a high inter-observer agreement rate (κ = .897, P < .001). Following consensus review, there was full concordance between RNA in situ hybridization and the current standard. CONCLUSION: Human papillomavirus testing by standalone automated RNA in situ hybridization on a clinical diagnostic platform currently available in routine diagnostic histopathology laboratories is a feasible alternative to the two-step algorithm of p16 and DNA in situ hybridization. Control tissue staining procedures need to be adapted to achieve the most accurate results.

Dysplasia and DNA ploidy to prognosticate clinical outcome in oral potentially malignant disorders.

BACKGROUND: Oral potentially malignant disorders are a clinical conundrum as there are no reliable methods to predict their behaviour. We combine conventional oral epithelial dysplasia grading with DNA ploidy analysis to examine the validity of this approach to risk assessment in a cohort of patients with known clinical outcomes. METHODS: Sections from diagnostic biopsies were assessed for oral epithelial dysplasia using the WHO grading system, and DNA ploidy analysis was performed using established methods. Patients reviewed for a minimum of 5 years who did not develop oral squamous cell carcinoma were classified as "non-transforming" cases. Patients that developed oral squamous cell carcinoma ≥ 6 months after the initial diagnostic biopsy were classified as having "malignant transformation." RESULTS: Ninety cases were included in the study. Seventy cases yielded informative DNA ploidy results. Of these 70 cases, 31 progressed to cancer. Oral epithelial dysplasia grading and DNA ploidy status were both significantly associated with clinical outcome (P < 0.05). Severe dysplasia had a hazard ratio of 3.50 (CI: 1.46, 8.45; P = 0.005) compared to cases with mild dysplasia. Aneuploidy had a hazard ratio of 2.09 (CI: 1.01, 4.32; P = 0.046) compared to cases with a diploid/tetraploid status. Receiver operating characteristic analysis gave an area under the curve of 0.617 for DNA ploidy status and 0.688 when DNA ploidy status was combined with dysplasia grading. CONCLUSION: Our findings suggest that combining dysplasia grading with DNA ploidy status has clinical utility which could be used to develop novel management algorithms.

European Laryngological Society position paper on laryngeal dysplasia Part II: diagnosis, treatment, and follow-up.

PURPOSE OF REVIEW: To give an overview of the current knowledge regarding the diagnosis, treatment, and follow-up of laryngeal dysplasia (LD) and to highlight the contributions of recent literature. The diagnosis of LD largely relies on endoscopic procedures and on histopathology. Diagnostic efficiency of endoscopy may be improved using videolaryngostroboscopy (VLS) and bioendoscopic tools such as Narrow Band Imaging (NBI) or Storz Professional Image Enhancement System (SPIES). Current histological classifications are not powerful enough to clearly predict the risk to carcinoma evolution and technical issues such as sampling error, variation in epithelial thickness and inflammation hamper pathological examination. Almost all dysplasia grading systems are effective in different ways. The 2017 World Health Organization (WHO) system should prove to be an improvement as it is slightly more reproducible and easier for the non-specialist pathologist to apply. To optimize treatment decisions, surgeons should know how their pathologist grades samples and preferably audit their transformation rates locally. Whether carcinoma in situ should be used as part of such classification remains contentious and pathologists should agree with their clinicians whether they find this additional grade useful in treatment decisions. Recently, different studies have defined the possible utility of different biomarkers in risk classification. The main treatment modality for LD is represented by transoral laser microsurgery. Radiotherapy may be indicated in specific circumstances such as multiple recurrence or wide-field lesions. Medical treatment currently does not have a significant role in the management of LD. Follow-up for patients treated with LD is a fundamental part of their care and investigations may be supported by the same techniques used during diagnosis (VLS and NBI/SPIES).

Targeted Next-Generation Sequencing and Allele-Specific Quantitative PCR of Laser Capture Microdissected Samples Uncover Molecular Differences in Mixed Odontogenic Tumors.

The molecular pathogenesis of mixed odontogenic tumors has not been established, and understanding their genetic basis could refine their classification and help define molecular markers for diagnostic purposes. Potentially pathogenic mutations in the component tissues of 28 cases of mixed odontogenic tumors were assessed. Laser capture microdissected tissue from 10 ameloblastic fibromas (AF), 4 ameloblastic fibrodentinomas (AFD), 6 ameloblastic fibro-odontomas (AFO), 3 ameloblastic fibrosarcomas (AFS), and 5 odontomas (OD) were screened by next-generation sequencing and results confirmed by TaqMan allele-specific quantitative PCR. BRAF p.V600E mutation in the mesenchymal component was shown in 4 of 10 AF (40%), 2 of 4 AFD (50%), 2 of 6 AFO (33%), and 2 of 3 AFS (67%), whereas all 5 OD were wild type for BRAF p.V600E. Mutation in the epithelial component was only observed in one AF and one AFO. One AFS contained an area of benign AF, and the mesenchymal component of both (AFS and AF) contained BRAF p.V600E, supporting the concept of malignant progression from a benign AF precursor. KDR, TP53, KIT, and PIK3CA single-nucleotide polymorphisms are reported. In conclusion, AF, AFD, AFO, and AFS show BRAF p.V600E in their mesenchymal component, unlike OD, which are BRAF wild type, suggesting that at least a subset of AF, AFD, and AFO are molecularly distinct from OD, and may represent distinct entities and be neoplastic.

DNA aneuploidy and tissue architecture in oral potentially malignant disorders with epithelial dysplasia assessed by a 10 locus FISH panel.

Subjectivity in oral dysplasia grading has prompted evaluation of molecular­based tests to predict malignant transformation. Aneuploidy detected by DNA image­based cytometry (ICM) is currently the best predictor but fails to detect certain high risk lesions. A novel multiplex fluorescence in situ hybridization (FISH) panel was used to explore possible explanations by detecting aneuploidy at the single cell level. FISH was compared to reference standard DNA ICM in 19 oral lesions with epithelial dysplasia and used to characterize the cellular architecture. Copy number variation at 3q28, 7p11.2, 8q24.3, 11q13.3 and 20q13.12 and matched chromosome specific loci were assessed by dual­color FISH to assess numerical and spatial patterns of copy number increase and gene amplification. FISH revealed wide variation in copy number at different loci. Only low level copy number gain was present and often in only a small proportion of cells, although usually with all or all but one locus (9/12). Four cases showed gene amplification, one at two loci. Some probes revealed an internal presumed clonal structure within lesions not apparent in routine histological examination. Both methods produced similar diagnostic results with concordance in detection of aneuploidy by both methods in 17 out of 19 samples (89%). We have shown that oral dysplastic lesions may contain very few aneuploid cells at a cellular level, high copy number gain is rare and changes appear to arise from large chromosomal fragment duplications. Single stem lines are relatively homogeneous for loci with copy number gain but there is a subclonal structure revealed by gene amplification in some lesions.

Data Set for the Reporting of Malignant Odontogenic Tumors: Explanations and Recommendations of the Guidelines From the International Collaboration on Cancer Reporting.

A data set has been developed for the reporting of excisional biopsies and resection specimens for malignant odontogenic tumors by members of an expert panel working on behalf of the International Collaboration on Cancer Reporting, an international organization established to unify and standardize reporting of cancers. Odontogenic tumors are rare, which limits evidence-based support for designing a scientifically sound data set for reporting them. Thus, the selection of reportable elements within the data set and considering them as either core or noncore is principally based on evidence from malignancies affecting other organ systems, limited case series, expert opinions, and/or anecdotal reports. Nevertheless, this data set serves as the initial step toward standardized reporting on malignant odontogenic tumors that should evolve over time as more evidence becomes available and functions as a prompt for further research to provide such evidence.

Predicting malignant progression in clinically high-risk lesions by DNA ploidy analysis and dysplasia grading.

The value of image cytometry DNA ploidy analysis and dysplasia grading to predict malignant transformation has been determined in oral lesions considered to be at 'high' risk on the basis of clinical information and biopsy result. 10-year follow up data for 259 sequential patients with oral lesions clinically at 'high' risk of malignant transformation were matched to cancer registry and local pathology database records of malignant outcomes, ploidy result and histological dysplasia grade. In multivariate analysis (n = 228 patients), 24 developed carcinoma and of these, 14 prior biopsy samples were aneuploid. Aneuploidy was a significant predictor (hazard ratio 7.92; 95% CI 3.45, 18.17) compared with diploidy (p < 0.001). The positive predictive value (PPV) for severe dysplasia was 50% (95% CI 31.5, 68.5) and for aneuploid lesions, 33.3% (95% CI 19.0, 47.6). Combined DNA aneuploidy and severe dysplasia increased PPV to 56.3% (95% CI 31.9, 80.6). Diploid-tetraploid and non-dysplastic status had high negative predictive values (NPV) of 94.6% (95% CI 91.4, 97.8) and 99.17% (95% CI 97.4, 100.8) respectively. DNA ploidy predicts malignant transformation well and combining it with dysplasia grading gave the highest predictive value. The predictive values reported here exceed those from other investigations to date.

Image cytometry DNA ploidy analysis: Correlation between two semi-automated methods.

BACKGROUND AND OBJECTIVES: Quantitation of cell DNA content, DNA ploidy, has been established as a research and prognostic technique for decades. A variety of instruments have been used although only a few commercially available systems have established quality assurance and published outcome data. The aim of this study was to compare two automated systems. METHODS: Nuclear monolayers were obtained from 112 oral biopsies by enzyme digestion and Feulgen staining. These were scanned on both the Fairfield and the Ploidy Work Station (PWS) systems. The overall ploidy diagnosis, number of epithelial nuclei, coefficient of variation (CV) and 5c exceeding rate (5CER) were compared by quantile-quantile plots, t test, Wilcoxon and Spearman's tests. RESULTS: The PWS system identified more nuclei (p < 0.0001) at a lower CV (p < 0.0001). Using the PWS system, fewer samples were classified as indeterminate. No difference between 5CER was found between systems (p > 0.54). There was complete concordance between the two systems in terms of DNA ploidy diagnosis. CONCLUSIONS: The PWS system is comparable to the Fairfield system for determination of DNA ploidy and has advantages that may lead to improved performance.

Meta-analysis of the predictive value of DNA aneuploidy in malignant transformation of oral potentially malignant disorders.

DNA aneuploidy is an imbalance of chromosomal DNA content that has been highlighted as a predictor of biological behavior and risk of malignant transformation. To date, DNA aneuploidy in oral potentially malignant diseases (OPMD) has been shown to correlate strongly with severe dysplasia and high-risk lesions that appeared non-dysplastic can be identified by ploidy analysis. Nevertheless, the prognostic value of DNA aneuploidy in predicting malignant transformation of OPMD remains to be validated. The aim of this meta-analysis was to assess the role of DNA aneuploidy in predicting malignant transformation in OPMD. The questions addressed were (i) Is DNA aneuploidy a useful marker to predict malignant transformation in OPMD? (ii) Is DNA diploidy a useful negative marker of malignant transformation in OPMD? These questions were addressed using the PECO method. Five studies assessing aneuploidy as a risk marker of malignant change were pooled into the meta-analysis. Aneuploidy was found to be associated with a 3.12-fold increased risk to progress into cancer (RR=3.12, 95% CI 1.86-5.24). Based on the five studies meta-analyzed, "no malignant progression" was more likely to occur in DNA diploid OPMD by 82% when compared to aneuploidy (RR=0.18, 95% CI 0.08-0.41). In conclusion, aneuploidy is a useful marker of malignant transformation in OPMD, although a diploid result should be interpreted with caution.