Methylation assessment of two DKK2 and DKK4 genes in oral squamous cell carcinoma patients

Background: Oral squamous cell carcinoma (OSCC) is one of the most important types of oral malignancies. DKK gene family members as well as DKK2/4 have critical roles in regulation of Wnt signaling as one of the main determining pathway in oral carcinogenesis. This study aimed to identify promoter methylation status of DKK2/4 genes to provide possible biomarkers for early detection and treatment of OSCC patients. Methods: A case control study was performed on 31 fresh tissues obtained from oral cavity of patients affect-ed by OSCC and 31 fresh corresponding tissues from normal healthy controls in Tehran and, between the years of 2016-2018. Purified DNA from tissue samples was subjected to bisulfite treatment and then methyla-tion specific polymerase chain reaction (MSP-PCR) was carried out on treated DNA samples. Results: DKK4 promoter was methylated in none of OSCC samples while it was methylated in 16.1% of healthy controls. 16.1% of OSCC samples were detected to be semimethylated and 22.6% of healthy normal samples were methylated for DKK2 promoter gene. Meaningful difference was found in DKK4 promoter methylation among OSCC patients and healthy controls. Significant correlation was found between DKK4 promoter methylation and tumor grade. The age of all enrolled samples was demonstrated to have strong effect on promoter methylation of studied genes. Conclusion: Hypomethylation of DKK2 and DKK4 genes in higher grades of OSCC samples may indicate the pivotal role of their expression in tumor cells invasion and progression through modulation of Wnt signaling pathway. Further study required to determine simultaneous expression of those genes and Wnt signaling ele-ments at mRNA and protein levels

Expression of Apoptosis Associated Proteins (Fas, Bcl2) in Oral Lichen Planus

BACKGROUND AND OBJECTIVE: Oral lichen planus (OLP) is a lymphocyte-mediated immunologic disorder in which basal keratinocytes appear to be the target of T-lymphocytes, and after “Apoptosis” phenomenon, it leads to hydropic degeneration of basal cells. Several proteins have been introduced in this process that may have major role in beginning and progression of apoptosis. The purpose of this study was to evaluate the immunohistochemical expression of two important pro-apoptotic (Fas) and anti-apoptotic (Bcl2) proteins in oral lichen planus and furthermore to evaluate the role of them in developing process of the lesion.METHODS: In this cross sectional study, the paraffin embedded tissue sections of 12 OLP specimens (9 buccal mucosa and 3 gingival mucosa) and 12 non-lesional specimens (8 irritation fibroma and 4 normal gingival mucosa), from archive of Oral and Maxillofacial Pathology Department of Dental School of Shahid Beheshti University of Medical Sciences were immunohistochemically stained using anti-Bcl2 and anti-Fas antibodies. The staining was eventually evaluated within epithelium and subepithelial connective tissue in each specimen. The intensity of staining was graded as weak (+), moderate (++) and high (+++). The results were statistically analyzed to determine any probably significant relationship. FINDINGS: The immunohistochemical expression of Fas between lesional and non-lesional groups in epithelial region was not significant (50% weak in both of them). No significant difference was also observed in expression of Fas in subepithelial region (83.3% weak and moderate versus 90.9% weak and moderate). The expression of Bcl2 showed no significant difference between two groups in epithelial region (100% weak versus 66.7% weak). Also a significant difference of subepithelial expression of Bcl2 was noted between two groups (91.7% moderate in lesional specimens versus 66.7% in non-lesional ones (p=0.01). CONCLUSION: The present study suggests that Bcl2 and Fas proteins probably may have no significant role in apoptosis in OLP and it is recommended to evaluate the other interfering proteins in this process