DNA ploidy in oral lichen planus, determined by image cytometry

Image-based DNA ploidy analysis aids prediction of malignant transformation in oral lichen planus

OBJECTIVES

To investigate the potential of image-based DNA ploidy analysis to predict malignant transformation in patients with oral lichen planus (OLP).

STUDY DESIGN

DNA ploidy analysis was performed on biopsy samples from 14 patients with OLP who underwent malignant transformation. As controls, 42 OLP lesions showing unusual clinical features suggesting a transformation risk and 68 samples of clinically and histologically typical OLP were included. Cases with dysplasia on initial biopsy were excluded. Eighty fibroepithelial polyps acted as methodologic controls. Epithelial nuclei were isolated from formalin-fixed paraffin embedded biopsy samples and monolayers stained with Feulgen for automated image cytometry to establish DNA content. Ploidy status was correlated to outcome using Kaplan-Meier analysis and log-rank Mantel-Cox tests.

RESULTS

All controls and typical OLP were diploid and none underwent malignant transformation in mean follow-up of 14 years (10-18 years). One unusual OLP developed carcinoma and all were diploid. The 14 patients with transformation developed 21 carcinomas. In the 11 patients who had a prior biopsy, 4 were aneuploid.

CONCLUSIONS

DNA ploidy analysis predicted malignant transformation in more than one third (36.4%) of patients with OLP with a preceding biopsy (n = 11). This premalignant nature could not have been diagnosed clinically or by histologic dysplasia assessment.

Photodynamic therapy in treatment of oral lichen planus

Oral lichen planus (OLP) is a relatively common chronic immunologic mucocutaneous disorder. Although there are many presenting treatments, some of them proved its failure. Recently, the use of photodynamic therapy (PDT) has been expanding due to its numerous advantages, as it is safe, convenient, and non-invasive and has toxic effect towards selective tissues. This article provides comprehensive review on OLP, its etiology, clinical features and recent non-pharmacological treatments. We also describe the topical PDT and its mechanisms. Our purpose was to evaluate the efficacy of PDT in treatment of OLP through collecting the data of the related clinical studies. We searched in PubMed website for the clinical studies that were reported from 2000 to 2014 using specific keywords: "photodynamic therapy" and "treatment of oral lichen planus". Inclusion criteria were English publications only were concerned. In the selected studies of photodynamic treatment, adult patients (more than 20 years) were conducted and the OLP lesions were clinically and histologically confirmed. Exclusion criteria were classical and pharmacological treatments of OLP were excluded and also the using of PDT on skin lesions of lichen planus. We established five clinical studies in this review where all of them reported improvement and effectiveness of PDT in treatment of OLP lesions. The main outcome of comparing the related clinical studies is that the photodynamic is considered as a safe, effective and promising treatment modality for OLP.

Evaluation of ploidy status using DNA-image cytometry of exfoliated mucosal cells in oral lichen planus

Background:

Oral lichen planus (OLP) is one of the potentially malignant disorders (PMDs) with a malignancy rate of 0.2-2%. Aneuploidy is considered to be one of the important markers for malignant transformation and DNA-image cytometry (DIC) has been successfully employed in oral mucosal PMDs and also in tumors of the cervix, lung and biliary tract.

Aims:

In this study, we intend to assess the ploidy status of exfoliated cells in OLP using DIC.

Materials and Methods:

Exfoliated cells from 48 patients with different subtypes of OLP (reticular, plaque type, erosive and atrophic) and 10 controls were stained using Feulgen reaction and assessed for integrated optical density using image analysis software and the ploidy status was assessed.

Results:

All the patients in the control group and most of the patients (93.5%) who had reticular or plaque type of OLP (29 out of 31) exhibited diploid nuclei in the smears, whereas 11 patients who had erosive or atrophic types of OLP showed aneuploid nuclei.

Conclusions:

The patients with erosive or atrophic types of OLP are at more risk and assessment of ploidy status by exfoliative cytology can be used as an adjuvant for diagnosis.

Global DNA methylation: uncommon event in oral lichenoid disease

OBJECTIVES

Accumulating evidence indicates that aberrant DNA methylation is closely related to oral carcinogenesis, and it has been shown that methylation changes might be used as prognostic biomarker in oral squamous cell carcinoma. Oral lichenoid disease (OLD) is the most common oral potentially malignant disorder in our region. The aim of this study was to perform the first wide DNA methylation study in OLD in order to investigate the relevance of DNA methylation changes in this premalignant disorder.

MATERIALS AND METHODS

Two different Illumina microarray platforms, namely the GoldenGate Cancer Panel I and the HumanMethylation27 DNA Analysis BeadChip, were utilized in the discovery phase to interrogate the methylation profile of 59 OLD cases and 9 healthy individuals. Top-ranked genes were further validated by pyrosequencing in a second sample set consisting of 160 OLD and 65 controls.

RESULTS

Our results show that the frequency of aberrant DNA methylation is rare in OLD, and this finding was further corroborated by pyrosequencing in the biological validation.

CONCLUSIONS

These findings reinforce the notion that molecular alterations associated with oral carcinogenesis do not seem to be common events in OLD, which in turn might explain the low rate of malignization of this disorder.

Oral lichen planus as a preneoplastic inflammatory model

Oral lichen planus (OLP) is a chronic oral inflammatory disease of unknown etiology. According to reports, 1-2% of OLP patients develop oral squamous cell carcinoma (OSCC) in the long run. While World Health Organization (WHO) classifies OLP as “a potentially malignant disorder,” it is still a matter of debate which mechanisms drive OLP to such a condition. The current hypothesis connecting OLP and OSCC is that chronic inflammation results in crucial DNA damage which over time results in cancer development. Initial studies investigating the OLP and OSCC link were mainly retrospective clinical studies. Over the past years, several amount of information has accumulated, mainly from molecular studies on the OLP malignant potential. This article is a critical review of whether OLP has a malignant potential and, therefore, represents a model of preneoplastic inflammation.