Evaluation of MYC status in oral lichen planus in patients with progression to oral squamous cell carcinoma

A New Multi-Color FISH Assay for Brush Biopsy-Based Detection of Chromosomal Aneuploidy in Oral (Pre)Cancer in Patients with Fanconi Anemia

BACKGROUND

Fanconi anemia (FA) is a rare inherited DNA instability disorder with a remarkably elevated risk of oral squamous cell carcinoma. These cancers can be detected with oral brush biopsy-based cytology even at early stages. This study aims to determine the diagnostic accuracy of a new multi-color fluorescent in situ hybridization (FISH) assay consisting of probes for CCND1, TERC, MYC and centromere of chromosome 6, as well as a 9p21 FISH assay consisting of probes for CDKN2A and centromere of chromosome 9 for the detection of oral (pre) malignant lesions in FA.

METHODS

(I) Cutoffs for the dichotomization of positive or negative multi-color FISH results are determined and (II) retrospectively validated by using archived oral brush biopsy specimens from individuals with Fanconi anemia. In addition, the specimens for cutoff determination were re-hybridized with the 9p21 FISH assay.

RESULTS

A cutoff of six or more chromosomal aneuploid cells for a positive FISH result was determined in the cutoff study on 160 biopsy specimens. The validating of this cutoff on 152 specimens showed at best a sensitivity of 87% and a specificity of 82.9%.

CONCLUSION

Multi-color FISH is a sufficient tool to detect chromosomal aneuploidy in oral (pre) malignant lesions of individuals with Fanconi anemia. However, some false positive results may hamper the application as an adjuvant method to oral brush biopsy-based cytology in an oral cancer surveillance program.

Bcl-2 and c-Myc expression in oral dysplasia and oral squamous cell carcinoma: An immunohistochemical study to assess tumor progression

Introduction

Oral cancer is a multistep process involving foul play of proto-oncogenes that induce cell proliferation, inactivation of tumor suppressor gene and cessation of programmed cell death. Among various proto-oncogenes, the nature and behavior of Bcl-2 and c-Myc in oral precancerous/cancerous lesions were obscured which require further assessment for better understanding of etiology, treatment and prognosis.

Aim

The aim of the study is to assess the expression of Bcl-2 and c-Myc in oral epithelial dysplasia and oral squamous cell carcinoma (OSCC).

Materials and Methods

This retrospective study of 70 (oral dysplasia [30], OSCC [30] and normal gingiva [10]) is immunohistochemically assessed for Bcl-2 and c-Myc for distribution, intensity, percentage of positive cells, localization and immunoreactive scores using ImageJ software.

Results

Bcl-2 showed 60% and 37% positivity within dysplasia and OSCC, respectively (P = 0.03); c-Myc showed 87% and 90% positivity within dysplasia and OSCC, respectively. In OSCC, c-Myc showed moderate intensity (P = 0.04). Average percentage of positive cells expressing c-Myc and Bcl-2 increased proportionally within grades of dysplasia (P = 0.000 and P = 0.008, respectively), whereas in OSCC, only c-Myc showed significant expression (P = 0.021). Localization of c-Myc was seen in the nucleus among OSCC (P = 0.01). c-Myc and Bcl-2 showed moderate immunoreactivity in dysplasia (P = 0.005 and P = 0.013, respectively), whereas in OSCC, moderate immunoreactivity of c-Myc (P = 0.05) was observed.

Conclusion

Variable expression of c-Myc and Bcl-2 reveals that these proteins act in synergism in early phases of carcinogenesis, whereas in later stages, due to the diminished activity of Bcl-2, c-Myc interacts incoordination with other oncogenes contributing to tumor progression.

A genome-wide association scan of biological processes involved in oral lichen planus and oral squamous cell carcinoma

BACKGROUND

In this study, the molecular mechanisms underlying malignant transformation from oral lichen planus (OLP) to oral squamous cell carcinoma (OSCC) were examined.

METHODS

High-throughput sequencing of long noncoding RNAs (lncRNAs) and mRNAs of normal subjects and patients with OLP and OSCC was conducted. RNA-seq reads were mapped, lncRNA and mRNA transcripts were assembled, and expression levels were estimated. The targets of lncRNAs were predicted. Finally, Gene Ontology (GO) and pathway enrichment analyses of differentially expressed genes (DEGs) and lncRNA targets were performed.

RESULTS

High-quality sequence data were generated and the mapping ratios for OSCC, normal, and OLP samples were high. In total, 820, 656, and 582 DEGs were obtained from OPL vs. normal, OSCC vs. normal, and OSCC vs. OPL, respectively. A total of 1721 known lncRNAs and 133 predicted lncRNAs and targets were obtained. Keratinization was significantly enriched by OSCC-related DEGs, but not OPL-related DEGs. The pathway of olfactory transduction was enriched by OPL- and OSCC-related DEGs. Defense response to virus and viral carcinogenesis were enriched by DEGs and lncRNA targets in all comparisons. GO term related to the metabolic process was enriched by lncRNA targets in the OPL vs normal comparison, and antigen processing and presentation via MHC class I was significantly enriched by lncRNA targets in the other 2 comparisons.

CONCLUSION

Keratinization and MHC class I antigen processing and presentation were activated during the malignant transformation from OLP to OSCC. Additionally, the olfactory transduction pathway may be important for OSCC.

Oral lichen planus

Lichen planus is an inflammatory mucocutaneous disease that can affect the skin, hair, nails, and mucosal surfaces. Mucosal sites of involvement include oral, genital, ocular, otic, esophageal, and, less commonly, bladder, nasal, laryngeal, and anal surfaces. Oral lichen planus is a mucosal variant of lichen planus, which tends to affect women more often than men, with a typically more chronic course and potential for significant morbidity. Treatment can be challenging, and there is potentially a low risk of malignant transformation; however, therapeutic benefits can be obtained with various topical and systemic medications. Clinical monitoring is recommended to ensure symptomatic control. Increasing awareness and recognition of this entity have continued to fuel advances in therapy and in our understanding of the disease.

Epigenetic Modifications and Accumulation of DNA Double-Strand Breaks in Oral Lichen Planus Lesions Presenting Poor Response to Therapy

Epigenetics refers to changes in cell characteristics that occur independently of modifications to the deoxyribonucleic acid (DNA) sequence. Alterations mediated by epigenetic mechanisms are important factors in cancer progression. Although an exciting prospect, the identification of early epigenetic markers associated with clinical outcome in premalignant and malignant disorders remains elusive. We examined alterations in chromatin acetylation in oral lichen planus (OLP) with distinct clinical behavior and compared the alterations to the levels of DNA double-strand breaks (DSBs). We analyzed 42 OLP patients, who had different responses to therapy, for acetyl-histone H3 at lys9 (H3K9ac), which is associated with enhanced transcription and nuclear decondensation, and the presence of DSBs, as determined by accumulation of phosphorylated γH2AX foci. Patients with high levels of H3K9ac acetylation failed to respond to therapy or experienced disease recurrence shortly after therapy. Similar to H3K9ac, patients who responded poorly to therapy had increased accumulation of DNA DSB, indicating genomic instability. These findings suggest that histone modifications occur in OLP, and H3K9ac and γH2AX histones may serve as epigenetic markers for OLP recurrence.

Immune-mediated diseases: what can be found in the oral cavity?

Immune-mediated diseases frequently affect oral mucosa, which may often be the first site of clinical manifestation. In this review, we describe the most important oral lesions related to inflammatory disorders and present their management and novel therapies. The review is based on an open PubMed literature search from 1980 to 2012 with relevant keywords. Pemphigus vulgaris, oral lichen planus, cicatricial pemphigoid, erythema multiforme, Stevens-Johnson syndrome, systemic lupus erythematosus, Sjögren's syndrome, and linear IgA dermatosis are the immune-mediated diseases with oral manifestations discussed. Etiology is unknown in most of these diseases, but recently some of them have been found to share common genes. Modern treatment of these diseases is based on drugs that interfere along the pathogenic mechanisms instead of the still commonly used palliative measures. However, the immunomodulatory drugs may also cause oral side effects, complicating the clinical picture. Therefore, consulting dental or oral medicine specialists can be necessary in some cases with various immune-mediated diseases.