DNA Content Analysis In Cancerous Risk Prediction Of Oral Potentially Malignant Disorders

Background Oral potentially malignant disorders is a general term that describes a series of different types of the diseases with a significantly increased cancerous risk compared with other oral mucosa, including oral leukoplakia, oral lichen planus,oral erythroplakia, oral submucous fibrosis, which are the main sources of oral squamous cell carcinoma. At present, histopathological diagnosis is still a golden standard of evaluating the malignant potential of OPMDs. However, the process is aggressive, time-consumingand poor compliance for patients. Therefore, it is necessary to find a non-aggressive, convenient,rapid and acceptable method for predicting high-risk OPMDs. DNA content analysis is a method for evaluating the physiological and pathological changes of cells by measuring the nuclear DNA content or ploidy. And this method reflected the development of pathology from morphometric description to quantitative analysis. DNA index value(DI)denotes DNA content and indirectly represents the number of chromosomes. Abnormal DNA content(aneuploidy) is a specific indication of malignance and can be used as a marker of malignant transformation. However, the possibility of using DNA content analysis technology to evaluate the cancerous risk of OPMDs patients is unknown. We hypothesize tha DNA content analysis technology may contribute to evaluate the cancerous risk of OPMDs patients.Methods1. DNA content of OPMDs patients was measured and analyzed to obtain the proper DI value for oral high-grade dysplasia/carcinoma in situ lesions with ROC curve.2. DNA content of different types of OPMDs was measured and its association with clinicopathological characteristics and cellular changes was analyzed. And its clinical value in evaluating the cancerous risk of different types of OPMDs was ascertained.3. DNA content of patients with oral leukoplakia, oral lichen planus and oral submucous fibrosis patients was measured and its association with clinicopathologicalcharacteristics and cellular changes was analyzed.Results1. A diagnostic criterion of DNA content analysis technology for evaluation of oral high-grade dysplasia/carcinoma in situ lesions was analyzed by ROC curve. The proper DI value satisfied that the number of cells with DI≥2.3 reached 2, which could be used as a diagnostic criterion for estimating oral high-grade dysplasia/carcinoma in situ lesions,and also for evaluating cancerous risk.2. DNA content of different types of OPMDs and its association with the clinicopathological characteristics and cellular changes was analyzed. The results were as follows:2.1 Logistic regression for oral leukoplakia indicated that tongue lesion and oral leukoplakia(III、IV stage) is the risk factor of abnormal DNA content in oral leukoplakia patients, the association of nuclear DNA content changes and cellular alteration was positive. Besides, nuclear morphometric parameters measurement suggested that DI value,nuclear area, mean radius were higher in high-grade dysplasia lesion than in low-grade dysplasia lesion, sphericity, mean intensity, entropy, and Fractal_dimen value were lower than in low-grade dysplasia lesion.2.2 Logistic regression for reticular oral lichen planus indicated that gender, age, lesion site, diet habit, smoking, alcoholintake and dysplasia degree were not the risk factors of abnormal DNA content of OLP(reticular) patients. However, the association of nuclear DNA content changes and cellular alteration was positive.2.3 Logistic regression for oral submucous fibrosis indicated that gender, age, lesion site,diet habit, smoking, alcohol intake and dysplasia degree were not the risk factors of abnormal DNA content of OSF patients. However, the association of nuclear DNA content changes and cellular alteration was positive.3. DNA content of different types of OPMDs was measured by DNA content analysis technology and its sensitivity and specificity for oral high-grade dysplasia leukoplakia was 67.74% and 66.67%, respectively. Positive prediction value was 61.76%. Negative prediction value was 72.22%. False positive rate was 38.24%. False negative value was27.78%. The sensitivity and specificity for oral high-grade dysplasia lichen planus was33.3% and 86.3%, respectively. Positive prediction value was 4.3%. Negative prediction value was 98.6%. False positive rate was 95.7%. False negative value was 1.4%. The sensitivity and specificity for oral dysplasia submucous fibrosis was 14.3% and 90.5%,respectively. Positive prediction value was 33.3%. Negative prediction value was 76.0%.False positive rate was 66.7%. False negative value was 24.0%.Conclusion1. DNA content analysis technology was applied for predicting cancerous risk of patients with OPMDs and we obtained a positive diagnostic criterion for oral high-grade dysplasia/carcinoma in situ lesions that the number of cells with DI≥2.3 reached 2. It could be applied to predicting cancerous risk.2. The risk factors of abnormal DNA content in different types of OPMDs were various with the application of DNA content analysis technology, which indicated that the disparity of risk factors in different OPMDs in clinical examination should be noticed and different preventive measurement should be taken.3. The sensitivity, specificity, positive prediction value, negative prediction value, false positive rate and false negative rate for predicting dysplasia lesions by DNA content analysis in different OPMDs was various, compared with pathological results: The sensitivity(67.74%), specificity(66.67%) for predicting oral leukoplakia was moderate,positive prediction value(61.76%) and negative prediction value(72.22%) was high,therefore, it was suited to screen patients with oral leukoplakia in clinical examination.The sensitivity(33.3% and 14.3%, respectively) for predicting malignant reticular oral lichen planus and oral submucous fibrosis was low, while the specificity( 86.3% and90.5%, respectively) was high, therefore, it was an important caution for screening malignant tendency of reticular oral lichen planus and oral submucous fibrosis.4. The association between DNA content change and cellular change was highly positive in different types of OPMDs(oral leukoplakia, oral lichen planus, oral submucous fibrosis) or different status of OPMDs(high-risk or low-risk). DNA content change occurred before cellular change, which indicated that DNA content analysis technology could be used as a significant supplement for traditional pathological diagnosis and also as a basis for early diagnosis of malignance in OPMDs.5. DNA content analysis technology was non-aggressive, convenient, acceptable and repeatable, so it was practicableas an auxiliary method for dynamically monitoring the process of OPMDs.