Evaluation of Static DNA Ploidy Analysis Using Conventional Brush Biopsy-Based Cytology Samples as an Adjuvant Diagnostic Tool for the Detection of a Malignant Transformation in Potentially Oral Malignant Diseases: A Prospective Study

Oral cancer detection and progression prediction using noninvasive cytology-based DNA ploidy approach

BACKGROUND

Despite the oral cavity being readily accessible, oral cancer (OC) remains a significant burden. The objective of this study is to develop a DNA ploidy-based cytology test for early detection of high-risk oral lesions.

METHODS

This retrospective study was conducted using 569 oral brushing samples collected from 95 normal and 474 clinically abnormal mucosa with biopsy diagnosis of reactive, low-grade or high-grade precancer or cancers. Brushing cells were processed to characterize DNA ploidy. A two-step DNA ploidy-based algorithm, the DNA ploidy oral cytology (DOC) test, was developed using a training set, and verified in test and validation sets to differentiate high-grade lesions (HGLs) from normal. The prognostic value of the test was evaluated by an independent outcome cohort, including progressed and non-progressing normal, reactive and low-grade lesions. Classification performance was assessed by accuracy, sensitivity, and specificity, while the prognostic value was evaluated by using the Cox proportional hazards analysis on 3-year progression-free survival (PFS).

RESULTS

The developed DOC test exhibited high accuracy for detecting HGLs in the test and validation sets, with a sensitivity of 0.97 and 0.96, respectively. Its application to the Outcome cohort demonstrated significant prognostic value for 3-year PFS (log rank, p < 0.001). Multivariate analysis showed that high-grade pathology was the only variable explaining positive DOC test, not age, smoking, or lesional site.

CONCLUSION

Clinical implementation of the DOC test could provide an effective screening method for detecting HGLs for biopsy and lesions at risk of progression.

Diagnosis of differentiated dysplasia as a variant of oral epithelial dysplasia

OBJECTIVES

The World Health Organization's definition of oral epithelial dysplasia includes differentiated dysplasia, which is defined by purely architectural abnormalities of oral mucosa without cytological changes. We analysed differentiated dysplasia's frequency, progression risk and correlation with oral brush cytology.

MATERIALS AND METHODS

Cytoarchitectural criteria and expression patterns of keratin 13/17 and ki67 were studied in oral biopsies clinically diagnosed with leukoplakia. Biopsies were assessed for dysplasia and its grade. Available brush cytology findings were obtained from clinical records.

RESULTS

We included 159 biopsies from 112 patients (33% differentiated dysplasia; 27% keratosis without dysplasia; oral epithelial dysplasia with atypia of mild, moderate and severe degree including invasive cancers in 9%, 8% and 7%, respectively). Keratin 13 loss and keratin 17 gain were higher in differentiated-dysplasia cases (p < 0.0001), which had the highest hypergranulosis frequency. Keratin 17 expression was associated with higher malignant-transformation rates (p = 0.0028). The transformation rate and time were comparable between dysplasia with atypia and differentiated-dysplasia cases, which had higher progression rates and shorter time periods than keratosis cases without dysplasia (p = 0.08). Cytology prior to differentiated dysplasia all indicated normal oral mucosa.

CONCLUSIONS

Keratin 17 but not oral brush cytology can help identify patients with differentiated dysplasia with higher risk for malignant transformation.