Also, Fusobacterium species known to be increased in oral squamous cell carcinoma (19-21) were recently reported to induce the upregulation of programmed cell death ligand 1 and extracellular signal-regulated kinase 1 (ERK1) pathway signaling to the MYC proto-oncogene in head and neck squamous cell carcinoma and thus potentially affect tumor biology and treatment responses (22). Here, MAPK3 is linked to oral cavity squamous cell carcinoma.