The expression of Methyltransferase-like 3 in dentigerous cyst and ameloblastoma

Abstract

Background: N6-methyladenosine (m6A), the most abundant internal RNA modification in mammals, plays a critical role in many forms of cancer. Methyltransferase-like 3 (METTL3) serves as the main catalytic subunit of the m6A writer and plays a role in the progression of head and neck squamous cell carcinoma. To date, the role of METTL3 in odontogenic lesions has never been investigated. This study aimed to examine METTL3 expression in dental follicles (DF), dentigerous cysts (DC), unicystic ameloblastoma (UA), and conventional ameloblastoma (conventional AM). Material and methods: The immunohistochemistry was performed using paraffin-embedded tissue samples. Seven cases of DF, 30 cases of DC, and 35 cases of AM (20 cases of UA and 15 cases of conventional AM) were included. The expression patterns, percentage of METTL3-positive cells, staining intensities, and immunoreactive scores (IRS) were examined. Results: The percentage of METTL3-positive cells was found to be significantly higher in the AM compared to DC and DF samples (p<0.01). Additionally, the percentage of METTL3-positive cells increased from the luminal/intraluminal subtype of UA, the mural subtype of UA, to the conventional AM (p<0.01). All AM samples had higher METTL3 cell staining intensity and IRS scores than the DF and DC samples (p<0.01). The mural subtype of UA and conventional AM also had significantly higher cell intensity and IRS scores than the luminal/intraluminal subtype of UA (p<0.05). Conclusions: The results of this study suggest that METTL3 might have a role in odontogenic lesions. METTL3 expression may be related to the aggressive behaviour of these lesions. However, the precise molecular mechanism of METTL3 in odontogenic lesions still needs to be elucidated.