CD274 and oral cavity squamous cell carcinoma: TPS, tumor proportion score; WD, well differentiated; MD, moderately differentiated; PD, poorly differentiated; TILS, tumor infiltrating lymphocytes; T, tumor; LVI, lymphovascular invasion; PNI, perineural invasion; WPOI, worst pattern of invasion; OSCC, oral squamous cell carcinoma; PD-L1, programmed death-ligand 1