A number of studies have reported the upregulation and functional roles of Jumonji domain-containing protein 6 (JMJD6) in various types of cancer. However, little is known regarding the clinical significance of JMJD6 in head and neck squamous cell carcinoma (HNSCC), particularly in terms of large-cohort data. In the present study, bioinformatics analysis was performed, using the University of California Santa Cruz Xena Browser and the Gene Expression Profiling Interactive Analysis 2 server, based on the Cancer Genome Atlas HNSCC cohort. In addition, a validation cohort was constructed based on 98 HNSCC cases. JMJD6 overexpression and knockdown, colony-formation, Transwell and cell viability assays were performed. JMJD6 was highly expressed in HNSCC samples and was associated with advanced pathological stage. However, no significant association was observed between JMJD6 expression levels and overall survival or disease-free survival times of patients with HNSCC. Subsequent in vitro assays indicated that overexpression of JMJD6 promoted malignant progression of HNSCC, by regulating epithelial-mesenchymal transition. Nevertheless, JMJD6 overexpression had no significant effects on the viability of HNSCC cells treated with 5-fluorouracil or cisplatin. Thus, it can be concluded that JMJD6 may function as a marker of HNSCC at advanced stage, however with no effect on drug resistance or prognosis. For patients with advanced HNSCC and high JMJD6 expression, rational chemotherapy may be more beneficial than radical surgery, considering their quality of life.
Keywords: Jumonji domain-containing protein 6; epithelial- mesenchymal transition; head and neck squamous cell carcinoma; malignant progression; prognosis.
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