Significance of Methyltransferase-like 5 Expression in Oral Squamous Cell Carcinoma.

Oral squamous cell carcinoma (OSCC) is a malignant tumour with high-local invasiveness and lymph node metastasis potential. It is associated with poor prognosis and postoperative cosmetic complications. Therefore, developing molecular targets for early detection, diagnosis, and treatment is imperative. Methyltransferase-like 5 (METTL5), a newly identified N6-methyladenosine (m6A) modification writer, has been shown to exhibit tumour-promoting functions in several cancers. However, the significance of METTL5 expression in OSCC remains unexplored. In this study, we performed gene expression and in silico analyses of METTL5 and related molecules using publicly available datasets. The clinicopathological significance of METTL5 was assessed by immunohistochemistry (IHC) in 62 OSCC specimens. Analysis of public databases revealed that METTL5 expression was highly elevated in head and neck SCC. Genes related to METTL5, including TP53RK-binding protein (TPRKB) and ZZ-type zinc finger and EF-hand domain protein 1 (ZZEF1), were identified. Furthermore, METTL5 expression levels were positively correlated with those of ferroptosis-related genes. IHC analysis revealed that METTL5 expression was associated with local tumour progression (P = .0367). Multivariate analysis revealed that METTL5 expression is associated with poor prognosis for overall survival (P = .0376). Our results suggest that METTL5 may serve as a new diagnostic and therapeutic target for OSCC.