Transepithelial Brush Biopsy - Oral CDx® - A Noninvasive Method for the Early Detection of Precancerous and Cancerous Lesions

A brief review of cytology in dentistry

Oral cytology is a non-invasive adjunctive diagnostic tool with a number of potential applications in the practice of dentistry. This brief review begins with a history of cytology in medicine and how cytology was initially applied in oral medicine. A description of the different technical aspects of oral cytology is provided, including the collection and processing of oral cytological samples, and the microscopic interpretation and reporting, along with their advantages and limitations. Applications for oral cytology are listed with a focus on the triage of patients presenting with oral potentially malignant disorders and oral mucosal infections. Furthermore, the utility of oral cytology roles across both expert (for example, secondary oral medicine or tertiary head and neck oncology services) and non-expert (for example, primary care general dental practice) clinical settings is explored. A detailed section covers the evidence-base for oral cytology as a diagnostic adjunctive technique in both the early detection and monitoring of patients with oral cancer and oral epithelial dysplasia. The review concludes with an exploration of future directions, including the integration of artificial intelligence for automated analysis and point of care 'smart diagnostics', thereby offering some insight into future opportunities for a wider application of oral cytology in dentistry.

DNA Image Cytometry for Screening the Carcinogenetic Risk of Oral Potential Malignant Disorders

Background: Oral Submucosal Fibrosis (OSF) and Oral Leukoplakia (OLK) are well-known oral potentially malignant disorders, and cases of Oral Submucosal Fibrosis concomitant Oral Leukoplakia (OSF+OLK) are now being reported clinically. DNA image cytometry is an objective and non-invasive method for monitoring the risk of precancerous lesions in the oral cavity. Methods: A total of 111 patients with clinically characterized oral mucosal lesions underwent simultaneous and independent histopathological and DNA imaging cytometry assessments. Clinical data were also collected for each patient. Results: The frequency of DNA content abnormality was higher in the tongue than in other oral sites (P = 0.003) for OLK. The frequency of DNA content abnormality was higher in the tongue than in other oral sites (P = 0.035) for OSF+OLK. The differences of DNA content abnormality in age, sex, dietary habit, smoking, and alcohol intake were not observed in OLK and OSF+OLK. The study indicates an association between DNA content abnormality and pathological examination in OSF+OLK ( χ2 test, P = 0.007). OLK showed higher sensitivity and specificity than OSF, while the sensitivity and specificity of OSF+OLK are higher than OLK only and OSF only. Conclusion: DNA image cytometry can be utilized as an adjunctive device for the initial detection of oral potentially malignant disorders that require further clinical management.

Genes Relevant to Tissue Response to Cancer Therapy Display Diurnal Variation in mRNA Expression in Human Oral Mucosa

Background:

To address a critical gap for application of cancer chronotherapy of when would be the best time(s) for treating an individual cancer patient, we conducted a pilot study to characterize diurnal variations of gene expression in oral mucosal tissue, which is vulnerable to damage from cancer therapies.

Methods:

We conducted RNA-seq assay on individual oral mucosal samples collected from 11 healthy volunteers every 4 hours (6 time points). Using a cosine-based method, we estimated the individual and average values of peak-time and amplitude for each gene. Correlations between gene expression peak-times and age was examined, adjusting for individual’s sleep timing.

Results:

Among candidate gene pathways that are relevant to treatment response, 7 of 16 genes (PER3, CIART, TEF, PER1, PER2, CRY2, ARNTL) involved in circadian regulation and 1 of 118 genes (WEE1) involved in cell cycle regulation achieved p-value ≤ 0.1 and relative amplitude>0.1. The average peak times were approximately 10:15 for PER3, CIART and TEF, 10:45 for PER1, 13:00 for WEE1, PER2 and CRY2, and 19:30 for ARNTL. Ranges in peak times across individuals differed by gene (e.g., 8 hours for PER1; 16.7 hours for WEE1). Older people had later peak times for PER1 (r = 0.77, p = 0.03) and PER3 (r = 0.69, p-value = 0.06).

Conclusion:

In oral mucosa, expression of some genes relevant to treatment response displayed diurnal variation. These genes may be candidates for development of biomarkers for optimizing individual timing of cancer therapy using non-invasively collected oral mucosa.

Evaluation of the Accuracy of Liquid-Based Oral Brush Cytology in Screening for Oral Squamous Cell Carcinoma

This study evaluates the accuracy of the results of liquid-based oral brush cytology and compares it to the histology and/or the clinical follow-ups of the respective patients. A total of 1352 exfoliated specimens were collected with an Orcellex brush from an identical number of oral lesions, then cytological diagnoses were made using liquid-based cytology. The final diagnoses in the study were 105 histologically proven squamous cell carcinomas (SCCs), 744 potentially malignant lesions and 503 cases of traumatic, inflammatory or benign hyperplastic oral lesions. The sensitivity and specificity of the liquid-based brush biopsy were 95.6% (95% CI 94.5–96.7%) and 84.9% (95% CI 83.0–86.8%), respectively. This led to the conclusion that brush biopsy is potentially a highly sensitive and reliable method to make cytological diagnoses of oral neoplasia. The main advantage of a brush biopsy over a scalpel biopsy is that it is less invasive and is more tolerated by the patients. Therefore, more lesions can be screened and more cancers can be detected at an early stage.