Genomewide miRNA profiling of oral lichenoid disorders and oral squamous cell carcinoma

OBJECTIVE

To dissect the aberrant microRNA profile of oral lichenoid disorders (OLD) by analyzing the larger set of OLD samples tested so far.

MATERIALS AND METHODS

MicroRNA expression profiles were assessed using TLDA card in 32 samples (16 OLD, 8 OSCC, and 8 control). The findings were validated using RT-qPCR in an independent cohort of 91 samples.

RESULTS

We identified 20 differentially expressed microRNAs in OLD, of which several are functionally related to cell proliferation, response to organic substances, or immune processes. Further validation of the top-ranked microRNAs revealed that they were all aberrantly expressed in OLD.

CONCLUSION

We have identified a new microRNA signature associated with OLD that may provide a meaningful basis for better understanding the physiopathology of the disease. In addition, we validated seven microRNAs whose expression was shown to be higher in OLD tissue in comparison with the control and OSCC tissues.

Mucocutaneous leishmaniasis must be included in the differential diagnosis of midline destructive disease: two case reports

Midline destructive lesions have multiple possible etiologies, which can be grouped into neoplastic, infectious, or vasculitis-associated. The purpose of these case reports and literature review was to highlight the need to include mucocutaneous leishmaniasis in the diagnosis of midfacial lesions in any patient who has lived in Leishmania-endemic areas because this entity meets all of the clinical criteria to be considered a form of midline destructive lesion. We present two cases of mucocutaneous leishmaniasis that occurred in a Bolivian male immigrant and a European male traveler to Panama, in whom lesions were misdiagnosed as different midline destructive lesions with different causes (Wegener, vasculitis, and natural killer or T-cell lymphoma [NKTL]). The conclusion of our work is that all patients with midline destructive lesions should undergo histologic and molecular studies to be evaluated for mucosal leishmaniasis, particularly patients whose clinical history suggests this possibility. In cases of uvular involvement, biopsy of this region might be a possible alternative to nasal biopsy.

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.

Urban legends series: oral candidosis

Candida species (spp) are commensal yeast that can only instigate oral infection (oral candidosis - OC) when there is an underlying predisposing condition in the host. We investigated four controversial topics on OC: (i) How can a microbiological determination of OC be made as Candida spp. are commensal yeasts and not all of them form hyphae or pseudohyphae during infection? (ii) Is median rhomboid glossitis (MRG) a manifestation of candidal infection? (iii) Can candidal infection cause palate papillary hyperplasia (PPH)? (iv) What is the best therapeutic treatment for denture-associated erythematous stomatitis (DAES)? Results from extensive literature searches, including a systematic review, suggested the following: (i) the diagnosis of OC merely on the basis of the presence of yeasts is an oversimplification of a complex process. No convincing evidence of a single test or method better able to discriminate the transition from candidal saprophytism to pathogenicity has been reported in the literature; (ii-iii) conclusive evidence of a direct aetiopathogenic relationship between MRG and PPH and candidal infection has not been found; and (iv) only limited evidence is available for any DAES treatment, thus making it impossible to make strong therapeutic recommendations.

Cytometric analysis of oral scrapings of patients with oral lichen planus

OBJECTIVE

Aneuploidy has been associated with malignant and premalignant oral lesions. In the past few years, its application in oral precancerous lesions and its prognostic meaning have been controversial issues. The aim of our study was to characterize alterations in DNA content by automated DNA image cytometry in oral scrapings of patients with oral lichen planus.

METHODS

Cytological samples from 40 patients clinicopathologically diagnosed with oral lichen planus were analysed by DNA image cytometry.

RESULTS

All the cases were classified as diploid, showing a predominant population of cells with normal DNA content (DNA index, 0.85-1.15). Atrophic/erosive lesions showed a higher percentage of tetraploid cells when compared with reticular/papular lesions but this was not statistically significant (P = 0.09).

CONCLUSIONS

Aneuploidy does not seem a common event in oral lichen planus lesions. However, we consider that the use of DNA image cytometry of oral scrapings may be an easy and helpful methodology in the follow-up of patients with these lesions.

Oral manifestations associated with human immunodeficiency virus infection in a Spanish population

A study was made of the oral manifestations in 396 patients with human immunodeficiency virus (HIV) infection. The following risk groups were established: intravenous drug users (79.5%), homosexuals (7.8%), homosexual intravenous drug users (3.3%), heterosexuals (8.1%) and hemophiliacs/transfusion patients (1.3%). The oral lesions, in decreasing order of frequency, were: periodontal disease (78.28%), candidiasis (65.65%), hairy leukoplakia (16.16%), herpes simplex virus lesions (5.30%). Kaposi's sarcoma (2.27%), recurrent aphthous ulceration (RAS) (1.01%), lichen planus (0.5%), non-Hodgkin's lymphoma (0.25%), tuberculous lesion of the tongue (0.25%) and ulcerations of uncertain etiology (0.25%). Attention is drawn to the greater predominance of these lesions in patients with CD4 values of less than 200/ mm3, compared with those who have higher lymphocyte counts.